**Technology TI**


[24] Available from: http://www.staywarmed.com [Accessed on February 3 2018]

February 3 2018]

194 Wearable Technologies

Technical Manual

[25] Available from: https://www.thewarmingstore.com/heating-pads.html [Accessed on

[26] Bahadir SK, Kalaoglu F, Jevsnik S. The use of hot air welding technologies for manufac

[27] AATCC TM128-2017. Wrinkle Recovery of Fabrics: Appearance Method. Research Triangle Park, NC, USA: Association of Textile, Apparel & Materials Professionals

turing E-textile transmission lines. Fibers and Polymers. 2015;**16**(6):1384-1394

**Chapter 10**

**Provisional chapter**

**The Comparison of Wearable Fitness Devices**

**The Comparison of Wearable Fitness Devices**

DOI: 10.5772/intechopen.76967

The wearable devices or wearable trackers help to motivate you during daily exercise or workouts. It gives you information about your daily routine or fitness by using wearable technology in combination with your smart phone to track your daily activities and fitness without the manual calculations or records that can be intrusive. Generally, companies display advertising for these kinds of products and depict them as good, userfriendly, and accurate. However, there are no subjective research results to prove the veracity of their words. Four popular wrist band-style wearable devices currently in the market were selected at the devices which are most popular (Withings Pulse, Misfit Shine, Jawbone Up24, and Fitbit Flex). The accuracy of tracking was one of the key components for fitness tracking, with some devices performing better than others. Accuracy in the tracking of daily activities such as walking, running, and sleeping is important. This research showed subjective and objective experiment results, which were used to compare the accuracy of four wearable devices in conjunction with user-friendliness. Satisfaction levels, the accuracy of tracking, and the opinion of each subject while using wearable device to track their daily activity were compared. The results determined that the cost-effectiveness was the Withings Pulse, followed by the Fitbit Flex, Jawbone Up24,

**Keywords:** wearable devices, Withings, Fitbit, misfit, jawbone, best tracker

There are many online reviews of wearable trackers, typically presenting different perspectives on the rankings. However, objective and factual information cannot match the subjective findings which convey further details about the devices, the participants in the experiments, or the particular reviewers involved. Further, there is no quantitative comparison table to show the results of subjects reviewed. For example, from the site of "Top Ten reviews" [1, 2],

> © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Kanitthika Kaewkannate and Soochan Kim

Kanitthika Kaewkannate and Soochan Kim

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76967

**Abstract**

and Misfit Shine.

**1. Introduction**

#### **The Comparison of Wearable Fitness Devices The Comparison of Wearable Fitness Devices**

DOI: 10.5772/intechopen.76967

Kanitthika Kaewkannate and Soochan Kim Kanitthika Kaewkannate and Soochan Kim

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76967

#### **Abstract**

The wearable devices or wearable trackers help to motivate you during daily exercise or workouts. It gives you information about your daily routine or fitness by using wearable technology in combination with your smart phone to track your daily activities and fitness without the manual calculations or records that can be intrusive. Generally, companies display advertising for these kinds of products and depict them as good, userfriendly, and accurate. However, there are no subjective research results to prove the veracity of their words. Four popular wrist band-style wearable devices currently in the market were selected at the devices which are most popular (Withings Pulse, Misfit Shine, Jawbone Up24, and Fitbit Flex). The accuracy of tracking was one of the key components for fitness tracking, with some devices performing better than others. Accuracy in the tracking of daily activities such as walking, running, and sleeping is important. This research showed subjective and objective experiment results, which were used to compare the accuracy of four wearable devices in conjunction with user-friendliness. Satisfaction levels, the accuracy of tracking, and the opinion of each subject while using wearable device to track their daily activity were compared. The results determined that the cost-effectiveness was the Withings Pulse, followed by the Fitbit Flex, Jawbone Up24, and Misfit Shine.

**Keywords:** wearable devices, Withings, Fitbit, misfit, jawbone, best tracker

### **1. Introduction**

There are many online reviews of wearable trackers, typically presenting different perspectives on the rankings. However, objective and factual information cannot match the subjective findings which convey further details about the devices, the participants in the experiments, or the particular reviewers involved. Further, there is no quantitative comparison table to show the results of subjects reviewed. For example, from the site of "Top Ten reviews" [1, 2],

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

the best wearable device reviewed was the Fitbit Flex, followed by the Withings Pulse, Jawbone, and Misfit. From this site, the table score was shown and compared but provided no details about where the information originated. Another example for a wearable tracker review site is "Best fitness tracker 2015." From Wearable Tech for your connected self [3], the top four trackers were Jawbone, Misfit, Fitbit, and Germinly, respectively. Online reviews rarely present objective and measurable comparison data, and the review content is usually only the opinions of bloggers. While the information is subjective in such cases, it is useful for customers who are considering purchasing a tracker, since the content can guide the customer to find the right product to meet their needs. However, customers would benefit greatly if the information offered included subjective comparison results which could let customers know which trackers would be the best fit for their requirements [4–6].

This research study provides a comparison among the leading wearable fitness-tracking devices available today, covering the accuracy, user-friendliness, and customer satisfaction. All the selected devices were of the wristband type and ranked within the top ten of the best 2015 products from reviews [1–3]. Four of these products were selected randomly: the Fitbit Flex (Fitbit Inc., San Francisco, California, USA) [7], the Withings Pulse (Consumer Electronics, Issy-les-Moulineaux, France) [8], the Misfit Shine (Msfit Inc., Apple Inc., Apple, Mitten Rd., Burlingame, California, USA) [9], and the Jawbone Up24 (Consumer Electronics, San Francisco, California, USA) [10–13]. The results will be shown as subjective and objective research results for the trackers with the best accuracy and user-friendliness by physical information from real users.

with wearable devices must therefore be easy to download. The app also serves to process the

**Figure 1.** The wearable devices in the experiments: (a) Fitbit flex, (b) Withings pulse, (c) misfit Shine, and (d) jawbone up.

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967 199

Seven healthy subjects participated in the experiments, comprised of six healthy men (adults aged 27–50 years, mean age of 31 years old, mean height 171.5 cm, and mean weight 68.18 kg)

Each participant wore each of the four devices for 1 week in turn, taking notes throughout of the results of their usage, their satisfaction levels, and their point of view regarding the benefits and shortcomings of each product. Upon completion of the testing cycle, the four devices were all tested in order to confirm the accuracy of the recorded data. The experiment details

During the course of this study, each participant wore each of the four wearable devices for 1 week periods, completing the evaluation form to assess their satisfaction levels upon completion of the week. The total test duration was 1 month. The evaluation form had two sections.

The participants provided scores using the five-point Likert scale for each category on each device, assessing the design, functions, and features after the 1-week test period when the device was worn every day. A score of five indicated a very positive assessment, while one

represented the poorest performance. The evaluation form comprised two parts:

and one healthy woman (adult aged 30 years, height 160 cm, and weight 42.1 kg).

collected data, store the data, and perform network activities [6].

**2.3. Experiment methods**

are outlined in Section 2.3b.

*2.3.2. Experimental methods*

*2.3.2.1. Subjective satisfaction of wearable device users*

**Section 1.** The Likert scale used to evaluate the devices.

*2.3.1. Subjects*

This paper reviews the following: (1) the overall specs of four devices were compared, (2) the user satisfaction for all four devices and compares the results of the satisfaction scores, (3) the opinion from user in experiments were explored, (4) the reviews of wearable devices of blogger or reviewer from internet site were compared with linking to the users' opinion in experiments, and (5) the accuracy and repeatability of activity tracking for each model were also recorded and compared.

### **2. Material and methods**

#### **2.1. Wearable devices used in the experiment**

The four wearable devices in the experiments were done randomly for wrist band devices available in Korea, chosen from ten devices in the top ten review rank [1–3] (see **Figure 1**). The four devices are Jawbone Up24, Misfit Shine, Fitbit Flex, and Withings Pulse. **Table 1** provides the comparable features of the four wearable devices.

#### **2.2. The user interface application (UI app) of each devices**

Most wearable devices differ in their user interface. The UI design for wearable devices should be simple, clear, and quick to navigate for users' comfort [3]. This is not an easy design feature since wearable wrist devices have to be small. As a result, devices which link to a smartphone though a UI app have become more popular among users. The smartphone apps which work

with wearable devices must therefore be easy to download. The app also serves to process the collected data, store the data, and perform network activities [6].

#### **2.3. Experiment methods**

#### *2.3.1. Subjects*

the best wearable device reviewed was the Fitbit Flex, followed by the Withings Pulse, Jawbone, and Misfit. From this site, the table score was shown and compared but provided no details about where the information originated. Another example for a wearable tracker review site is "Best fitness tracker 2015." From Wearable Tech for your connected self [3], the top four trackers were Jawbone, Misfit, Fitbit, and Germinly, respectively. Online reviews rarely present objective and measurable comparison data, and the review content is usually only the opinions of bloggers. While the information is subjective in such cases, it is useful for customers who are considering purchasing a tracker, since the content can guide the customer to find the right product to meet their needs. However, customers would benefit greatly if the information offered included subjective comparison results which could let customers know

This research study provides a comparison among the leading wearable fitness-tracking devices available today, covering the accuracy, user-friendliness, and customer satisfaction. All the selected devices were of the wristband type and ranked within the top ten of the best 2015 products from reviews [1–3]. Four of these products were selected randomly: the Fitbit Flex (Fitbit Inc., San Francisco, California, USA) [7], the Withings Pulse (Consumer Electronics, Issy-les-Moulineaux, France) [8], the Misfit Shine (Msfit Inc., Apple Inc., Apple, Mitten Rd., Burlingame, California, USA) [9], and the Jawbone Up24 (Consumer Electronics, San Francisco, California, USA) [10–13]. The results will be shown as subjective and objective research results for the trackers with the best accuracy and user-friendliness by physical information from real users.

This paper reviews the following: (1) the overall specs of four devices were compared, (2) the user satisfaction for all four devices and compares the results of the satisfaction scores, (3) the opinion from user in experiments were explored, (4) the reviews of wearable devices of blogger or reviewer from internet site were compared with linking to the users' opinion in experiments, and (5) the accuracy and repeatability of activity tracking for each model were

The four wearable devices in the experiments were done randomly for wrist band devices available in Korea, chosen from ten devices in the top ten review rank [1–3] (see **Figure 1**). The four devices are Jawbone Up24, Misfit Shine, Fitbit Flex, and Withings Pulse. **Table 1** provides

Most wearable devices differ in their user interface. The UI design for wearable devices should be simple, clear, and quick to navigate for users' comfort [3]. This is not an easy design feature since wearable wrist devices have to be small. As a result, devices which link to a smartphone though a UI app have become more popular among users. The smartphone apps which work

which trackers would be the best fit for their requirements [4–6].

also recorded and compared.

198 Wearable Technologies

**2. Material and methods**

**2.1. Wearable devices used in the experiment**

the comparable features of the four wearable devices.

**2.2. The user interface application (UI app) of each devices**

Seven healthy subjects participated in the experiments, comprised of six healthy men (adults aged 27–50 years, mean age of 31 years old, mean height 171.5 cm, and mean weight 68.18 kg) and one healthy woman (adult aged 30 years, height 160 cm, and weight 42.1 kg).

Each participant wore each of the four devices for 1 week in turn, taking notes throughout of the results of their usage, their satisfaction levels, and their point of view regarding the benefits and shortcomings of each product. Upon completion of the testing cycle, the four devices were all tested in order to confirm the accuracy of the recorded data. The experiment details are outlined in Section 2.3b.

#### *2.3.2. Experimental methods*

#### *2.3.2.1. Subjective satisfaction of wearable device users*

During the course of this study, each participant wore each of the four wearable devices for 1 week periods, completing the evaluation form to assess their satisfaction levels upon completion of the week. The total test duration was 1 month. The evaluation form had two sections.

**Section 1.** The Likert scale used to evaluate the devices.

The participants provided scores using the five-point Likert scale for each category on each device, assessing the design, functions, and features after the 1-week test period when the device was worn every day. A score of five indicated a very positive assessment, while one represented the poorest performance. The evaluation form comprised two parts:


**Part 1.** Satisfaction assessment of properties and features.

Data sharing Only friends who

**Table 1.** The comparison table of features and function of four wearable devices.

**Part 2.** Satisfaction scores for the device metric function.

This section invited participants to provide a satisfaction rating score for the properties and features of each of the four devices. Factors to consider included the hardware, or general design, the user interface and UI app, the synchronicity, the battery, and the user-friendliness.

**Features Specifications Jawbone Up24 Fitbit Flex Withings Pulse Misfit**

Touchscreen Capacitive finger Capacitive finger Capacitive

Alarm function Yes Yes Yes Yes Data sharing Yes Yes Yes Yes Material Wearable body type Rubber Rubber Rubber Anodized

> iOS 5.1 or greater, Android 4.0 (Ice Cream Sandwich)

you already have

or later

known

(Bluetooth)

Water resistance Not too high Yes No Yes (up to

Sensor network Bluetooth Bluetooth Bluetooth Bluetooth

Screen type Dual LED Five LEDs OLED (black lit) 12 LED and

Screen size (inch) No (LED bar) No (LED bar) 1.69 No (12 LED

Three gyro sensors No No No No Magnetometer No No No No Pressure sensor No No No No GPS No No No No Altimeter No No No No

> above iOS/Android

Yes Yes Yes Yes

Window Xp/Vista/7/8 Android 2.3.3

270 days 30 days 10 days 30 days

No Yes Yes Yes

only Mac OS X 10.5 or

Yes Yes Yes

over or iOS

30 m)

blink

Blink)

aircraftgrade aluminum

Pair to iOS

(Bluetooth)

201

Capacitive touch

Wireless (Bluetooth) Bluetooth Wireless

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967

finger

Resistance function

Screen and display

Sensor type Three-axis

Smartphone Smartphone

UI interface History tracking (days)

Social network data Sharing

Synchronization Sync type Wireless

accelerometer

operation system

Computer data storage (Web app)


**Table 1.** The comparison table of features and function of four wearable devices.

**Part 1.** Satisfaction assessment of properties and features.

**Features Specifications Jawbone Up24 Fitbit Flex Withings Pulse Misfit**

Product released Released(USA) 13-Nov-13 6-May-13 27-Jun-13 16-Sep-14

Fitbit Inc. Consumer

http://www.fitbit.com www.withings.

San Francisco, California, USA

Announced(USA) 13-Nov-13 7-Jan-13 6-Jan-13 16-Sep-14 Present availability Available Available Available Available

Weight Small, 19 g Small, 16.4 g 8 g 9.4 g

 225mAh Lithium polymer battery

Changeable battery No No No Yes

Full charging time 3 hours 4 hours 2 hours No

Step counting Yes Yes Yes Yes Distance No Yes Yes Yes Calories Yes Yes Yes No Sleep Yes Yes Yes Yes Heart rate No No Yes No Fitness analytics Yes Yes Yes Yes Wind No No No No 3D mapping No No No No Speed No No No No SpO2 No No No Yes Goal tracking No Yes No No

Tracking Metric Motion Yes Yes Yes Yes

Battery life 4–6 months 4–6 months 6 months 3 months

large, 23 g large, 18.9 g

6.1 × 6.1 inch Small, 5.5 × 0.6 inch 1.7 × 0.87 × 0.33

Large, 6.3 × 8.2 inch

Yes Yes Yes No

Up to 10 days Up to 14 days Up to 14 days Up to

Electronics

Issy les Moulineaux, France

com

clip-on

inch

Lithium-ion polymer

Misfit Inc.

Apple Inc., Apple, Mitten Rd., Burlingame, California, USA

www. withings. com

Wearable/ clip-on

1.08 × 0.13 × 1.08 inch

CR2032 coin cell

180 days

Electronics

California, USA

Country San Francisco,

Information Link http://jawbone.

com

Type Smart watch Watch style Wearable/clip-on Wearable/

General Price in market \$150 \$100 \$100 \$95

Company detail Company name Consumer

200 Wearable Technologies

Dimension (W×D×H)

Battery Type LiMnO2

Rechargeable battery

Usable per one time charged (advertised)

> This section invited participants to provide a satisfaction rating score for the properties and features of each of the four devices. Factors to consider included the hardware, or general design, the user interface and UI app, the synchronicity, the battery, and the user-friendliness.

**Part 2.** Satisfaction scores for the device metric function.

This section invited participants to provide a satisfaction rating score for the metric function on each of the devices. This encompasses measures such as step count, distance, calories, sleep, and analysis of nutrition.

**Section 2.** Participants' personal opinions about the devices.

This section allowed participants to record their opinions on the positive and negative aspects of each device. The personal comments of the participants can then be presented subsequently.

#### *2.3.2.2. Testing the devices for accuracy and repeatability*

The functionality offered by each of the four devices is similar; the differences lie within the user interfaces, applications, and the algorithms used for calculations. The most important criteria from the perspective of the user are accuracy and repeatability, since these aspects will guide the users to reliability achieve their targets. However, the accuracy and repeatability of any of these devices will also depend to a certain extent of personal factors such as the weight, height, gender, and age of the user. The physical data will therefore be required along with the subjective perceptions of the users in order to determine the accuracy and repeatability of the four devices.

To conduct the test, the devices were placed on the participants' wrists as shown in **Figure 2**. Following the recording of test data during the experiment, the real data were then measured in terms of distance so as to compare with the recorded data from the devices in order to determine the accuracy.

The percentage of accuracy and repeatability for the four devices are presented in this paper. The repeatability was calculated using Cronbach's Alpha, SPSS program (SPSS V.2012, IBM Corporation, USA). Subsequently, we scaled scoring among the four devices from the best to the lowest, as explained in **Table 2**.

**3. Results and discussion**

After each of the four 1-week test periods, the participants completed the evaluation form providing their Likert scores concerning the device attributes and qualities until UI applica-

**Figure 3a** shows the mean score for the five conditions of features, including device design, battery use, smartphone synchronization, UI applications, and ease of use. On the other hand, **Figure 3b** shows the mean and standard deviation score of the satisfaction when using the four main functions of each device, including step counting, sleep tracking, distance tracking,

tion. The satisfaction scale applied is described in detail in **Table 3**.

**Figure 2.** The subjects wore all four devices to measure the accuracy and repeatability of results.

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967 203

**Table 2.** Scale of accuracy and repeatability when compared among four devices for each experiment.

4 The highest accuracy or repeatability among the four devices

1 The lowest accuracy or repeatability among the four devices

3 The second highest accuracy or repeatability among the four devices 2 The second lowest accuracy or repeatability among the four devices

**3.1. User satisfaction**

**Scale (point) Meaning**

5 Very useful and very satisfied

2 Less useful and less satisfied 1 Not useful and not satisfied

4 Moderately useful and moderately satisfied

3 Slightly useful and slightly satisfied

**Table 3.** The scale of evaluation and corresponding meanings.

**Scale (point) Meaning**

**Experiment 1**. Distance traveled and step counting of indoor walking.

Subjects wore the four devices (**Figure 2**) and then walked straight across the indoor experiment court. Total distance was 48 meters for ten trials per person. The data for step counting and distance represented for each device were collected.

**Experiment 2**. Distance traveled and step counting of treadmill running (jogging).

Subjects wore the four devices (**Figure 2**) and then ran or jogged on a treadmill at 8 km/h [13, 14] for 1 minute, repeated for five trials. The real data record from the treadmill was collected to compare with the real distance calculation from the treadmill's LCD.

**Experiment 3**. Step counting when walking up and down stairs.

Subjects wore four devices as shown in **Figure 2**; then walked up four flights of stairs, repeated the experiments for five times; and then walked down the stairs, repeated for five times.

Upon completion of the data gathering stage, scores were assigned to each device for accuracy and repeatability using a scale rating of one to four, where four indicates the best performance among the four tested products, as shown in **Table 3**.

**Figure 2.** The subjects wore all four devices to measure the accuracy and repeatability of results.


**Table 2.** Scale of accuracy and repeatability when compared among four devices for each experiment.

### **3. Results and discussion**

#### **3.1. User satisfaction**

This section invited participants to provide a satisfaction rating score for the metric function on each of the devices. This encompasses measures such as step count, distance, calories,

This section allowed participants to record their opinions on the positive and negative aspects of each device. The personal comments of the participants can then be presented subsequently.

The functionality offered by each of the four devices is similar; the differences lie within the user interfaces, applications, and the algorithms used for calculations. The most important criteria from the perspective of the user are accuracy and repeatability, since these aspects will guide the users to reliability achieve their targets. However, the accuracy and repeatability of any of these devices will also depend to a certain extent of personal factors such as the weight, height, gender, and age of the user. The physical data will therefore be required along with the subjective perceptions of the users in order to determine the accuracy and repeatability of

To conduct the test, the devices were placed on the participants' wrists as shown in **Figure 2**. Following the recording of test data during the experiment, the real data were then measured in terms of distance so as to compare with the recorded data from the devices in order to

The percentage of accuracy and repeatability for the four devices are presented in this paper. The repeatability was calculated using Cronbach's Alpha, SPSS program (SPSS V.2012, IBM Corporation, USA). Subsequently, we scaled scoring among the four devices from the best to

Subjects wore the four devices (**Figure 2**) and then walked straight across the indoor experiment court. Total distance was 48 meters for ten trials per person. The data for step counting

Subjects wore the four devices (**Figure 2**) and then ran or jogged on a treadmill at 8 km/h [13, 14] for 1 minute, repeated for five trials. The real data record from the treadmill was col-

Subjects wore four devices as shown in **Figure 2**; then walked up four flights of stairs, repeated the experiments for five times; and then walked down the stairs, repeated for five times.

Upon completion of the data gathering stage, scores were assigned to each device for accuracy and repeatability using a scale rating of one to four, where four indicates the best perfor-

**Experiment 2**. Distance traveled and step counting of treadmill running (jogging).

lected to compare with the real distance calculation from the treadmill's LCD.

**Experiment 1**. Distance traveled and step counting of indoor walking.

and distance represented for each device were collected.

**Experiment 3**. Step counting when walking up and down stairs.

mance among the four tested products, as shown in **Table 3**.

sleep, and analysis of nutrition.

202 Wearable Technologies

the four devices.

determine the accuracy.

the lowest, as explained in **Table 2**.

**Section 2.** Participants' personal opinions about the devices.

*2.3.2.2. Testing the devices for accuracy and repeatability*

After each of the four 1-week test periods, the participants completed the evaluation form providing their Likert scores concerning the device attributes and qualities until UI application. The satisfaction scale applied is described in detail in **Table 3**.

**Figure 3a** shows the mean score for the five conditions of features, including device design, battery use, smartphone synchronization, UI applications, and ease of use. On the other hand, **Figure 3b** shows the mean and standard deviation score of the satisfaction when using the four main functions of each device, including step counting, sleep tracking, distance tracking,


**Table 3.** The scale of evaluation and corresponding meanings.

**Opinion about features Jawbone Up24 Fitbit flex Withings pulse Misfit Shine**

Food and nutrient calculation is its main function; it is very easy to use

It has the battery indicator to check the battery status, but it has high battery consumption

synchronization but always lost connection

1. It required smartphone

3. The device is confusing sometimes; it needs to be reset

4. Tracking problem when walking upor downstairs

5. High battery consumption

6. Data is not updated sometimes

**Table 4.** Comparison table of user feedback (summarized from seven subjects for each device).

7. Calories count is not easy to use and only European foods are in the database

2. Slow synchronization

Slow

The Pulse O2 measurement is its main function; it can help you detect your heart status

It has battery indicator to check battery status; battery can be used in too many days

Fast synchronization, data can send via Bluetooth and WiFi

1. Design is not modern

2. If the battery of witlings is low, the device cannot connect. The data transfer which is shown on the smartphone is inaccurate

3. The sleep tracking is not automatic

5. Automatic loss of

6. Screen is difficult to see in sunlight

7. No Nutrient analysis

syncing

The goal tracking is its main function; you can check how your status to seek the goal

205

It is comfortable; no need to charge the

Fast synchronization but easy to lose connection

1. It required smartphone

2. It has slow synchronization, not always updated real

3. Sometimes it gave inaccurate display

when walking up- or downstairs (inaccurate)

5. The display does not always respond to finger tapping

6. No nutrient analysis

7. Always disconnected from mobile phone

time

4. Not water proof 4. Tracking problem

battery

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967

Metric function Sleep tracking is

Battery It can be charged

Synchronization Slow

Others (disadvantage/

cons)

its main function because the sleep tracking report is very detailed, but it is difficult to use

only on the USB

synchronization

1. The devices required smartphone to display

2. No display on

3. Sleep tracking results are difficult to use and nonautomatic

4. Cannot share the data through social

5. Most expensive among four devices

6. It is not fully waterproof

7. Slow Synchronization

network

itself

cable

**Figure 3.** (a) Bar graph comparison of mean and standard deviation of the satisfaction score by subjects when using the devices. (b) Bar graph comparison of mean and standard deviation of the satisfaction score by subjects when using the devices.

and caloric analysis. The case of heart rate analysis does not exist in the evaluation score because only the Withings Pulse possessed this function.

From the subjective results, the Withings Pulse device had the highest satisfaction score, followed by the Misfit Shine, Jawbone Up24, and Fitbit Flex.

The results in **Table 4** show the opinions, which imply that subjects gave similar answers to two persons about the features and functions of each device.



**Figure 3.** (a) Bar graph comparison of mean and standard deviation of the satisfaction score by subjects when using the devices. (b) Bar graph comparison of mean and standard deviation of the satisfaction score by subjects when using the

and caloric analysis. The case of heart rate analysis does not exist in the evaluation score

From the subjective results, the Withings Pulse device had the highest satisfaction score, fol-

The results in **Table 4** show the opinions, which imply that subjects gave similar answers to

**Opinion about features Jawbone Up24 Fitbit flex Withings pulse Misfit Shine**

Device design is good and sleek; it is good for any sports

Easy to tap on screen to active

It can be used to take shower without worrying

1. UI app is colorful and has fun display, easy to use

2. Nutrient analysis is very detailed

3. Dashboard shows the overall daily activity

Design is not attractive, but the fabric band can help to hold it as wrist

Display is big and shows the activity tracking without any smart phone sync

According to manual, it is not water resistant

1. Display is easy to use and colorful

2. Dashboard log is easy to check all

3. The heart rate function is good to check your health

activity

status

Design is very attractive, beautiful, and fashionable

Display is as clock; it can also be used as a watch, but in the sunshine it is hard to see the LED display

It is designed for sports as swimming; water resistant is too

1. Display is beautiful and easy to understand

2. It has goal tracker to lead you to know your daily activity

3. App can be shared to your friends; it shows how your friends seek the goal

high

band

because only the Withings Pulse possessed this function.

lowed by the Misfit Shine, Jawbone Up24, and Fitbit Flex.

two persons about the features and functions of each device.

Design Light and good for

Display Easy to tap the

Water resistant It is water resistant,

UI app 1. Tips of app and

any sport

screen to active

but according to the manual, it is less water proof

how to use always shown on home screen

2. Enjoyable fitness

3. Dashboard shows the overall daily activity

tracker

devices.

204 Wearable Technologies

**Table 4.** Comparison table of user feedback (summarized from seven subjects for each device).

From **Table 4**, it is apparent that all four devices were both satisfactory and unsatisfactory to the subjects. As mentioned in Topic 3.2, the summary of the opinions came from the similar meaning answers from two or more subjects. The most clearly apparent problem across all devices was the automatic loss of synchronization, which presents a problem in updating data, and leads to incorrect reports. However, all of the participants were able to use all of the devices easily with minimal instruction, or less, so the user-friendliness was good in all cases. The summary of the different claims from the reviewers on various commercial websites reviewing the devices is shown in **Tables 5–8**. Considering the five top-ranked sites from a Google search, it is clear that the leading reviews are well known due to the large numbers of people visiting those topranked sites to investigate wearable devices. The comments and descriptions of the reviewers can inform customers who might wish to purchase one of the devices for themselves. The drawback is that although the reviews can appear helpful, it is difficult to know whether the views have been influenced by the companies themselves or if they are in fact genuine independent perspectives. It is possible for an opinion to come only from one reviewer who used a product.

**Reviewer name**

Raphael Mumford

Weebly Jawbone Up24 review

> Smart activity tracker, Jawbone Up24 review

Matt Swider Jawbone Up24 review

Michael Sawh Jawbone Up24 review

**Site name Reviewed date Reference** 

**site**

**Advantages (pros) Disadvantage (cons)**

know

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967

button

—

—

—

1. No display for on-demand stats

2. Doesn't have a web app

3. Works with just ten Android phones

4. 2.5 mm stereo jack for

3. App is sluggish at times

1. No built-in screen

charging

Jawbone UP

2. Slim, stylish design 2. Shorter battery than

— 4. Not waterproof

add friends you already

207

2. No website interface, only phone app

3. Hair can stuck in cap

1. No measurement of stairs climbed

2. Just for iOS devices

4. Overcount arm movement as steps

8-Nov-14 [11] 1. Wireless syncing 1. Social sharing: can only

2. Can be used in the

3. Deep sleep and light

4. "Smart Wake" alarms

6. Holds battery charge for up to 7 days

band fits your wrist comfortably

2. Long lifetime battery (up to a week for per full-energy charging)

3. Wireless syncing via Bluetooth without any

4. Quick charging — 5. Smart alarm — 6. Expandable storage

7. Price is cheap —

hassle

capability

added

comfort

syncing

feature

2. Stylish and lightweight

3. Very soft rubber for

4. iOS and Android compatible

support for real-time

3. Great silent alarm

5. Usability design 5. No screen

shower

sleep data

for naps

Not mentioned [12] 1. Well-designed

24-Mar-14 [13] 1. Wireless syncing

26-Mar-14 [13] 1. Bluetooth smart

This section is explored because of the pros and cons of using reviewer claims, whether or not they may be similar or different than the customer's and seven subjects' opinions in this study. **Tables 5–8** shows the summarized data of advantages (pros) and disadvantages (cons) for each of the four devices from reviewers on the websites.

**Jawbone UP24** subjects' opinions and the reviewers imply that it has a good design and fits comfortably. The UI app is colorful and easy to understand. The sleep tracker is very smart and also has good alarm functions. However, disadvantages of the device (cons) include the design lacking a screen; it is not fully water proof, and the battery charger is complex.

**Withings Pulse** has good primary features, such as the heart rate function. The display itself is big and can show the results tracking. The data log uses Bluetooth syncing or wireless for automatic updating. The Withings design does not, however, provide an attractive case, with direct sunlight making it hard to read the display. Furthermore, there is no automatic sleep tracking function.

**Fitbit Flex** has a slender and attractive design, is wholly waterproof, and is equipped with good social features. However, the Fitbit Flex has weak points in that it has no screen; the food log and calories tracking are not easy to use, and the tapping screen is sometimes confusing.

**Misfit Shine** looks both fashionable and elegant. It is ideal for watersport enthusiasts since it is fully waterproof. It offers a goal tracking feature which motivates users to achieve their targets. The battery is exchanged rather than recharged. However, the device works only with iOS, and while there are plans to introduce Android compatibility, this has not yet taken place. A smartphone is necessary to check the tracking status, and there are sometimes problems which arise when poor syncing from device to smartphone results in inaccuracies.

#### **3.2. Accuracy and repeatability of the four devices**

From **Table 9**, it can be seen that the Withings Pulse achieved the best results for the accuracy and repeatability of measurements for indoor walking, at 99.9% for accuracy and 86% for repeatability. **Figure 4** shows the results for all of the four devices. The lowest scores for accuracy and repeatability were measured for Misfit.


From **Table 4**, it is apparent that all four devices were both satisfactory and unsatisfactory to the subjects. As mentioned in Topic 3.2, the summary of the opinions came from the similar meaning answers from two or more subjects. The most clearly apparent problem across all devices was the automatic loss of synchronization, which presents a problem in updating data, and leads to incorrect reports. However, all of the participants were able to use all of the devices easily with minimal instruction, or less, so the user-friendliness was good in all cases. The summary of the different claims from the reviewers on various commercial websites reviewing the devices is shown in **Tables 5–8**. Considering the five top-ranked sites from a Google search, it is clear that the leading reviews are well known due to the large numbers of people visiting those topranked sites to investigate wearable devices. The comments and descriptions of the reviewers can inform customers who might wish to purchase one of the devices for themselves. The drawback is that although the reviews can appear helpful, it is difficult to know whether the views have been influenced by the companies themselves or if they are in fact genuine independent perspectives. It is possible for an opinion to come only from one reviewer who used a product. This section is explored because of the pros and cons of using reviewer claims, whether or not they may be similar or different than the customer's and seven subjects' opinions in this study. **Tables 5–8** shows the summarized data of advantages (pros) and disadvantages (cons)

**Jawbone UP24** subjects' opinions and the reviewers imply that it has a good design and fits comfortably. The UI app is colorful and easy to understand. The sleep tracker is very smart and also has good alarm functions. However, disadvantages of the device (cons) include the

**Withings Pulse** has good primary features, such as the heart rate function. The display itself is big and can show the results tracking. The data log uses Bluetooth syncing or wireless for automatic updating. The Withings design does not, however, provide an attractive case, with direct sunlight making it hard to read the display. Furthermore, there is no automatic sleep tracking function.

**Fitbit Flex** has a slender and attractive design, is wholly waterproof, and is equipped with good social features. However, the Fitbit Flex has weak points in that it has no screen; the food log and calories tracking are not easy to use, and the tapping screen is sometimes confusing. **Misfit Shine** looks both fashionable and elegant. It is ideal for watersport enthusiasts since it is fully waterproof. It offers a goal tracking feature which motivates users to achieve their targets. The battery is exchanged rather than recharged. However, the device works only with iOS, and while there are plans to introduce Android compatibility, this has not yet taken place. A smartphone is necessary to check the tracking status, and there are sometimes problems which arise when poor syncing from device to smartphone results in inaccuracies.

From **Table 9**, it can be seen that the Withings Pulse achieved the best results for the accuracy and repeatability of measurements for indoor walking, at 99.9% for accuracy and 86% for repeatability. **Figure 4** shows the results for all of the four devices. The lowest scores for

design lacking a screen; it is not fully water proof, and the battery charger is complex.

for each of the four devices from reviewers on the websites.

206 Wearable Technologies

**3.2. Accuracy and repeatability of the four devices**

accuracy and repeatability were measured for Misfit.


Raphael Mumford Withings Pulse wireless activity tracker review

DC Rainmaker Withings

Pulse In-Depth Review

**Site name Reviewed date Reference** 

**site**

Not mentioned [16] 1. Easy to clip on

**Advantages (pros) Disadvantages (cons)**

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967

> 1. Not automatically detect the time and switch to sleep mode

209

2. Lack of silent alarm

3. The screen is not easy to read under the

4. Syncing to PC is impossible

sunlight

—

—

—

—

—

others

demand

3. Good battery life 3. Does not automatically

—

1. The unit is a bit chubbier than some

2. Does not track heart rate all 24 hours, only on

go from sleeping mode to nonsleeping, must switch over manually

something thanks to a silicone and metal clip

2. Large OLED screen touch screen and easy history browsing

3. Free iOS and Android

4. Accurate heart rate monitoring

6. Charging easily via a standard micro-USB to USB power cable on a computer or on a smartphone

7. Free account on Withings.com to store your health and fitness

8. Worn as a wristband to track your activity

9. Log your foods and weight, and get the perfect balance between activity and nutrition

heart rate quickly and

2. Display is clear and easy to understand

4. Good ability to connect to third-party platforms/sites

data

21-Nov-13 [17] 1. Can record resting

and sleep

easily

5. Low power consumption. The battery has a long lifetime of 2 weeks

apps

**Table 5.** Summary of pros and cons from reviewer opinions for the jawbone UP24.



208 Wearable Technologies

Matthew Miller

**Reviewer name**

Weebly Withings Pulse

smart activity tracker review

**Site name Reviewed date Reference** 

**Table 5.** Summary of pros and cons from reviewer opinions for the jawbone UP24.

**Site name Reviewed date Reference** 

**site**

**site**

Not mentioned [15] 1. Captures heart rate

Jawbone UP24 6-Dec-14 [14] 1. Well-designed band

**Advantages (pros) Disadvantage (cons)**

now

—

—

**Advantages (pros) Disadvantages (cons)**

—

—

—

—

—

—

—

—

1. No altimeter to measure stairs climbed

2. Limited just to iOS for

3. Hangs up on jackets and long sleeve shirts

1. Not shower-safe

2. Easy to misplace (leave in pockets, etc.)

that fits comfortably long battery life

2. Flawless syncing via

3. Integrated Microsoft Office software

6. Expandable storage

4. Charges up quickly — 5. Great sounding front facing stereo speakers

Bluetooth

capability

information

2. Captures flights of stairs climbed and elevation climbed

3. Check running stats (duration and distance traveled) in real time

4. Automatic wireless

6. Screen with constant

7. Discreet and multiple

8. Battery charge lasts up

9. App also pulls in data

10. Internet site available for Withings devices

5. Captures sleep (duration, quality, light versus deep sleep, interruptions)

syncing

feedback

ways to wear

to 14 days

wirelessly


Raphael Mumford

Articles by Suzie

Bethany Gordon

Fitbit Flex review

Fitbit Flex Only year

mentioned (2015)

**Table 7.** Summarized data of pros and cons from reviewer opinions for the Fitbit flex.

Fitbit Flex wireless activity Review

**Site name Reviewed date Reference** 

**site**

Not mentioned [21] 1. Slim and stylish design for

the perfect fit

gentle vibration

your progress

motivation

from

dongle

running low.

of my activity

2. Track everything relating to your activities and sleeps, except for stairs quantity

3. Waking up silently thanks to

4. Five built-in LED indicator lights for better monitoring of

7. Connecting and competing with other athletes for a better

8. A long lifetime battery of 5–7 days per charge

Mar 15 [22] 1. It is easy to wear all the time 1. Only charge the

9. Two options in size and two options in color you can choose

3. Upload status automatically through the Bluetooth or

4. Notification alert to let me know when my battery is

5. Learning curve to get the most from it; the Dashboard is a colorful and has fun display

[23] 1. Excellent interface 1. This device does not

2. Excellent app 2. Only view your data

5. Water resistance is included — 6. The Fitbit App for iPhone and Android devices to track your real-time stats, set goals, log food and other workout information, and then represent your sleep trends

**Advantages (pros) Disadvantages (not so** 

**cons)**

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967

—

—

—

—

—

—

cable

menu

—

—

have a screen

your phone.

from your computer or

2. Water resistant 2. It takes a lot of work

tracker with the USB

in the beginning to establish your food

3. Sometimes have trouble tapping the tracker into sleep mode

1. Lack of stair tracking

211

2. A tiny LCD display is

not included

**Table 6.** Summarized data of pros and cons from reviewer opinions for the Withings pulse.



**Reviewer name**

210 Wearable Technologies

Review: Withings Pulse with built-in heart rate monitor

Withings Pulse Activity tracker review

Mikey Campbell

Julie Strielmeier

Weebly Fitbit Flex

review

**Site name Reviewed date Reference** 

**Site name Reviewed date Reference** 

**site**

**site**

**Table 6.** Summarized data of pros and cons from reviewer opinions for the Withings pulse.

**Advantages (pros) Disadvantages (not so** 

**Advantages (pros) Disadvantages (cons)**

3. Flexible carry options 3. Wear ability limited to belt clip

data presentation

2. Sleep data is not always accurate, and the detailed data could use some beefing up to show

3. It does not work with a stand along computer

more info

—

2. Display lag, touchscreen issues

2. shower-safe water resistance 2. Always visible if

3. Very adjustable wristband 3. No screen on device

5. Wireless syncing 5. Have to tap band

10-Aug-14 [20] 1. Comfy wristband form factor 1. Does not track flights

4-Nov-13 [18] 1. Variety of sensors 1. Lack of meaningful

2. Impressive data accuracy

23-Aug-13 [19] 1. Size of the pulse 1. Syncing problem 2. Can see all the important info right on the device itself instead of like some devices

3. Wireless syncing is a

4. The built-in heart rate sensor is super easy

real plus too

to use

4. Progress lights tell you how close you are to reaching your

6. Great integration with existing fitness apps like

7. Strong social features including adding friends with a FitBit device or other FitBit users, a competition

MyFitnessPal

daily goal

**cons)**

One)

progress

for me)

—

of stairs (like the FitBit

worn with short sleeves

to show you detailed information on goal

4. Very hard to attach to the wrist and can pop off (while canoeing,

repeatedly to enter/exit sleep mode or to stop the silent alarm

6. Chopping veggies can trigger sleep mode

**Table 7.** Summarized data of pros and cons from reviewer opinions for the Fitbit flex.


The total scores for each device are shown in **Table 9** and **Figure 4**. The Withings Pulse has the highest score for both repeatability and accuracy. The lowest accuracy and repeatability were recorded by Misfit. With regard to opinions from seven subjects and also the table of reviewers, we concluded that both the Fitbit and the Misfit have difficulties in detecting when the

**Reviewer name**

Mikey Campbell Review: Shine activity monitor

**Site name Reviewed date**

**Reference site**

tracker

swimmers

2. Includes clip and wristband mounts

4. Fully waterproof for

12-Nov-13 [28] 1. Great design 1. Clunky tagging method 2. Easy to understand graphical readout

> Withings 99.9 0.86 Misfit 92.4 0.69 Fitbit 99.6 0.72

> Withings 97.2 0.83 Misfit 97.8 0.79 Fitbit 96.4 0.81

> Withings 97.2 0.83 Misfit 97.8 0.79 Fitbit 96.4 0.81

Jill Duffy Misfit Shine 10-Dec-13 [27] 1. Best looking activity

**Table 8.** Summary of pros and cons from reviewer opinions for the misfit Shine.

**Experiments and results Devices Accuracy (%) Repeatability**

Indoor walking straight Jawbone 97.7 0.55

Walking up/downstairs Jawbone 97 0.89

Walking on treadmill Jawbone 97 0.89

**Table 9.** Comparison of accuracy and repeatability for the devices.

**Advantages (pros) Disadvantage (cons)**

3. Functions as a watch 3. No Web app

— 5. Dashboard lacks

3. Long battery life 3. LEDs unusable in bright sunlight

1. Limited data analysis

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967

services

counting

2. Light in features

2. No integration with other

213

4. No syncing between iOS and Android apps

weight-tracking and calorie


**Table 8.** Summary of pros and cons from reviewer opinions for the misfit Shine.

**Reviewer name**

212 Wearable Technologies

Bethany Gordon

Weebly Misfit shine

activity tracker review

**Site name Reviewed date**

Misfit Shine Only year

Kristen Buck Misfit Shine Only year

mentioned (2015)

mentioned (2015)

**Reference site**

**Advantages (pros) Disadvantage (cons)**

2. Shine attachment can come unsecured (can pop out of sports band)

3. Time-telling feature suggests this could replace a watch, yet it lacks all other watch features including alerts

4. Limited info on "screen": does not have a full digit-

5. Shine's tapping-based interface can be frustrating

1. Tapping the screen is the only way to see your

2. The Shine does not always respond to tapping

certain way to display time and daily progress

1. The Misfit Shine only works for iOS

altimeter to count how many flights of stairs you

3. Not compatible with Android devices

based display

to use

—

—

—

progress

3. Convenient to wear 3. It has to sit on your arm a

2. Water resistant 2. Does not have an

climb

—

8-Nov-14 [24] 1. Waterproof 1. Sleep data is basic 2. Wireless data transfer (when placed near the

4. Elegant aluminum

5. On-device feedback to let you know how close you are to reaching a goal

6. No recharging. Just replace the watch battery when it runs out (~4–6 months)

7. Partnership with Pebble watch allows you to use the Pebble as a Misfit Shine

8. Social features including a leaderboard, profile, and

2. Comfortable band making the Misfit Shine extremely easy to use

4. Water resistant —

the size of a quarter and undeniably attractive.

3. Great activity monitor for swimmers and surfers

4. Can wear it in different ways to track different activities more accurately

newsfeed

[25] 1. The interchangeable design

[26] 1. Misfit Shine is about

3. Can track swimming and

device)

cycling

design


**Table 9.** Comparison of accuracy and repeatability for the devices.

The total scores for each device are shown in **Table 9** and **Figure 4**. The Withings Pulse has the highest score for both repeatability and accuracy. The lowest accuracy and repeatability were recorded by Misfit. With regard to opinions from seven subjects and also the table of reviewers, we concluded that both the Fitbit and the Misfit have difficulties in detecting when the

Bluetooth syncing or wireless. The design, however, is not particularly attractive, since it is hard to read the display under exposure to sunlight and the sleep tracking feature does not

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967 215

**Fitbit Flex** has a slender and attractive design, is wholly waterproof, and offers a number of social features. However, the Fitbit Flex has weak points. It has no screen, the food log and calories tracking are not easy to use, the food log is hard to learn for beginners, and the tap

**Misfit Shine** has an attractive, elegant, and fashionable design. It is fully water proof and especially good for water sports. The goal tracking function leads the user to achieve the goal, and the battery does not need to recharge, only exchange. In contrast, the Misfit Shine can only be used with iOS. Although compatibility with Android is a planned future feature, it has not yet been implemented. A smartphone is necessary to display the tracking status since the device does not have its own display. When loss of syncing with the smartphone occurs,

**Section 2.** The experiments compared the accuracy and repeatability of the devices awarded among four wearable devices. The score four points for the best accuracy and repeatability. The score three, two, and one point for the second, third, and fourth device, respectively. The most accurate and repeatable device was the Withings, second Jawbone, third Fitbit, and

In contrast, Misfit had the highest score for design and hardware. Thus, physical design is also

Therefore, the Withings device provided the greatest satisfaction and was the most userfriendly from the perspective of the users. It was also the highest ranked for accuracy and repeatability in step count and distance tracking. Tracking accuracy is vital in fitness tracking, but in personal tracking, there are differences which stem from age, gender, weight, and height. The tracking of daily activities including sleeping, waking, or running will also be important, and the results of the tests indicate that the greatest accuracy is achieved by the

As the results showed, the cause that made the Misfit Shine and Fitbit Flex have the lowest score of accuracy and repeatability was stair tracking. These two devices could not track activity when the subjects walked on stairs or climbed. For this reason, users were disappointed

In this study, it was unclear by inspection of the deep or shallow sleep of the subjects whether the wearable devices could measure accurately. Thus, true value comparison was not shown

The results in this study relative to step counting and others are subjective enough to assist in the buying process for potential wearable device purchasers. One more fact from the seven subjects' opinions is that four of the seven subjects would not buy this kind of wearable device. It interferes with their arm while in use and is uncomfortable with syncing the data log for daily tracking. One more important reason is that data gave uncorrected reports because of automatic loss of syncing. Nowadays, wearable technology has the greatest potential impact in the fields of health and fitness. However, it can also be influential for gaming and other forms of entertainment.

work automatically.

fourth Misfit.

in these devices.

screen is sometimes confusing.

this can result in data inaccuracies.

appreciated by users in addition to other devices.

Withings device in all these categories for accuracy and repeatability.

in this research. However, future studies may advance this knowledge.

**Figure 4.** The summary of the accuracy and repeatability scores among the four devices.

wearer is ascending or descending steps. Along with the subject's experiments in **Table 5** and **Figure 4**, the scores from experiments of walking up and down stairs are both lowest in cases of accuracy and repeatability. This resulted in the overall scores for the Misfit and the Fitbit being the lowest among the four wearable devices in terms of repeatability and accuracy.

The total scores for each device are shown in **Figure 4**. The Withings Pulse has the highest score for both repeatability and accuracy. The lowest accuracy and repeatability were recorded by Misfit.

### **4. Discussion and conclusion**

We attempted to evaluate the best wearable device from the four devices selected. This study focused on both objective and subjective methods to get the physical comparison results. The results are independent of manufacturers' claims. The main two sections of experiment testing verified the quality of the devices, both objectively and subjectively.

**Section 1.** Eight categories were classified in the form for evaluation of satisfaction levels: synchronization, hardware design, UI app, sleep tracking, step count, nutrition analysis, calories, battery, and user-friendliness. The most satisfying device based on the participants' rankings was the Withings, followed the Misfit, Jawbone, and Fitbit.

Further to the information gathered in Section 1, a summary was compiled from the viewpoints of the seven participants and online reviewers. The summary revealed that each device had its own strengths and weaknesses. The evaluation form and satisfaction scores thus allowed the subjective records of genuine users to be presented for each of the four devices. The opinions of the participants and those of the online reviewers were shown to be similar, leading to the following conclusions:

**Jawbone UP24** is well designed and fits comfortably for the subjects. The UI app is colorful and easy to understand. The sleep tracker is very smart and also has good alarm functions. However, disadvantages (cons) include the design not having a screen, it is not water proof, and the battery charger is very complex.

**Withings Pulse** has good features such as the heart rate function, which can detect pulse rate. It is just one of the functions that the Withings has. The display on the Withings device is large enough to show the results tracking. The data log can be updated automatically via Bluetooth syncing or wireless. The design, however, is not particularly attractive, since it is hard to read the display under exposure to sunlight and the sleep tracking feature does not work automatically.

**Fitbit Flex** has a slender and attractive design, is wholly waterproof, and offers a number of social features. However, the Fitbit Flex has weak points. It has no screen, the food log and calories tracking are not easy to use, the food log is hard to learn for beginners, and the tap screen is sometimes confusing.

**Misfit Shine** has an attractive, elegant, and fashionable design. It is fully water proof and especially good for water sports. The goal tracking function leads the user to achieve the goal, and the battery does not need to recharge, only exchange. In contrast, the Misfit Shine can only be used with iOS. Although compatibility with Android is a planned future feature, it has not yet been implemented. A smartphone is necessary to display the tracking status since the device does not have its own display. When loss of syncing with the smartphone occurs, this can result in data inaccuracies.

wearer is ascending or descending steps. Along with the subject's experiments in **Table 5** and **Figure 4**, the scores from experiments of walking up and down stairs are both lowest in cases of accuracy and repeatability. This resulted in the overall scores for the Misfit and the Fitbit being the lowest among the four wearable devices in terms of repeatability and accuracy.

The total scores for each device are shown in **Figure 4**. The Withings Pulse has the highest score for both repeatability and accuracy. The lowest accuracy and repeatability were

We attempted to evaluate the best wearable device from the four devices selected. This study focused on both objective and subjective methods to get the physical comparison results. The results are independent of manufacturers' claims. The main two sections of experiment test-

**Section 1.** Eight categories were classified in the form for evaluation of satisfaction levels: synchronization, hardware design, UI app, sleep tracking, step count, nutrition analysis, calories, battery, and user-friendliness. The most satisfying device based on the participants' rankings

Further to the information gathered in Section 1, a summary was compiled from the viewpoints of the seven participants and online reviewers. The summary revealed that each device had its own strengths and weaknesses. The evaluation form and satisfaction scores thus allowed the subjective records of genuine users to be presented for each of the four devices. The opinions of the participants and those of the online reviewers were shown to be similar,

**Jawbone UP24** is well designed and fits comfortably for the subjects. The UI app is colorful and easy to understand. The sleep tracker is very smart and also has good alarm functions. However, disadvantages (cons) include the design not having a screen, it is not water proof,

**Withings Pulse** has good features such as the heart rate function, which can detect pulse rate. It is just one of the functions that the Withings has. The display on the Withings device is large enough to show the results tracking. The data log can be updated automatically via

ing verified the quality of the devices, both objectively and subjectively.

**Figure 4.** The summary of the accuracy and repeatability scores among the four devices.

was the Withings, followed the Misfit, Jawbone, and Fitbit.

recorded by Misfit.

214 Wearable Technologies

**4. Discussion and conclusion**

leading to the following conclusions:

and the battery charger is very complex.

**Section 2.** The experiments compared the accuracy and repeatability of the devices awarded among four wearable devices. The score four points for the best accuracy and repeatability. The score three, two, and one point for the second, third, and fourth device, respectively. The most accurate and repeatable device was the Withings, second Jawbone, third Fitbit, and fourth Misfit.

In contrast, Misfit had the highest score for design and hardware. Thus, physical design is also appreciated by users in addition to other devices.

Therefore, the Withings device provided the greatest satisfaction and was the most userfriendly from the perspective of the users. It was also the highest ranked for accuracy and repeatability in step count and distance tracking. Tracking accuracy is vital in fitness tracking, but in personal tracking, there are differences which stem from age, gender, weight, and height. The tracking of daily activities including sleeping, waking, or running will also be important, and the results of the tests indicate that the greatest accuracy is achieved by the Withings device in all these categories for accuracy and repeatability.

As the results showed, the cause that made the Misfit Shine and Fitbit Flex have the lowest score of accuracy and repeatability was stair tracking. These two devices could not track activity when the subjects walked on stairs or climbed. For this reason, users were disappointed in these devices.

In this study, it was unclear by inspection of the deep or shallow sleep of the subjects whether the wearable devices could measure accurately. Thus, true value comparison was not shown in this research. However, future studies may advance this knowledge.

The results in this study relative to step counting and others are subjective enough to assist in the buying process for potential wearable device purchasers. One more fact from the seven subjects' opinions is that four of the seven subjects would not buy this kind of wearable device. It interferes with their arm while in use and is uncomfortable with syncing the data log for daily tracking. One more important reason is that data gave uncorrected reports because of automatic loss of syncing.

Nowadays, wearable technology has the greatest potential impact in the fields of health and fitness. However, it can also be influential for gaming and other forms of entertainment. Wearable technology can create a vividly realistic and immersive environment in real time. This concept is not new. Modern prototypes are moving away from bulky technology, such as large goggles and backpacks, toward smaller, lightweight, and more mobile systems.

[2] 10TopTen reviews "Fitness Tracker Review and Comparisons". Available on: http://

The Comparison of Wearable Fitness Devices http://dx.doi.org/10.5772/intechopen.76967 217

[3] Best Fitness Tracker 2015 from Wearable Tech for your connected self. Available on:

[4] Meredith A, Holland A, Kevin G. Accuracy of smartphone application and wearable devices for tracking physical activity data. JAMA. 2015:625-626. DOI: 10.1001/jama.2014.

[5] Rienzo M, Rizzo F, Parati G, Brambilla G, Ferratini M, Castiglioni P. MagIC system: A new textile-based wearable device for biological signal monitoring. Applicability in

[6] Kaewkannate K, Soochan K. A comparison of wearable fitness devices. BMC Public

[8] Withings Pulse Ox". Available on: http://www.withings.com/eu/withings-pulse.html

[11] Jawbone Up24 Review. Available on: http://www.bestfitnesstrackerreviews.com/jaw-

[12] Smart activity tracker Jawbone Up Review. Available on: http://www.smartactivity-

[13] JawboneUp24 Review. Available on: http://www.techradar.com/reviews/gadgets/

[14] Jawbone UP24 Review: Make Each Day Better Wirelessly. Available on: http://www. zdnet.com/pictures/jawbone-up24-review-make-each-day-better-wirelessly/

[15] Withings Pulse Smart Activity Tracker Review. Available on: http://www.bestfit-

[16] Withings Pulse wirless Activity tracker review. Available on: http://www.smartactivity-

[17] Withings Pulse In-Depth Review. Available on: http://www.dcrainmaker.com/2013/11/

[18] Review: Withings Pulse with built-in heart rate monitor". Available on: http://appleinsider.com/articles/13/11/05/review-withings-pulse-with-built-in-heart-rate-monitor [19] Withings Pulse Activity tracker review. Available on: http://the-gadgeteer.com/2013/08/27/

[20] Fitbit Flex Review. Available on: http://www.bestfitnesstrackerreviews.com/fitbit-flex-

nesstrackerreviews.com/withings-smart-activity-tracker-review.html

http://www.wareable.com/fitness-trackers/the-best-fitness-tracker

Daily Life and Clinical Setting. 2016. DOI: 10.1109/IEMBS.2005.1616161

Health. 9, 2016;**16**:433. DOI: 10.1186/s12889-016-3059-0

[7] Fitbit Flex. Available on: https://www.fitbit.com/kr/flex

[9] Misfit. Available on: http://misfit.com/?locale=en

[10] Jawbone. Available on: https://jawbone.com/

jawbone-up24-review-1230596/review

bone-up24-review.html

tracker.net/jawbone-up24

tracker.net/withings- pulse

withings-depth-review.html

review.html

withings-pulse-activity-tracker-review/

fitness-trackers-review.toptenreviews.com/

17841

On the author's viewpoint, the most comparable of the wearable device is that it cannot display itself but needs the smartphone to involve the metric data and reports. However, the storage of mobile phone to store and display the results is bigger, but it is inconvenient to use both at the same time. And yet, presently many fitness-tracking applications are available through the online store for free without any special or specific device. It is very convenience to whom that focuses in their healthy or fitness tracker. Even though the report of it is not guarantee 100% of accuracy, it is the easiest way to track their activity without any payment. Thus, the companies who produced the fitness tracker or wearable devices to the market in this highly competitive market will continuously develop new eye-catching products and reduce errors using the voices and opinions of users from this study to reach a wider market in the future. The relationship between technology and esthetics must go together, such as unobtrusive design, very sleek and modern and light weight, waterproof function, and many choices to recharge batteries. Basic activities such as walking or climbing stairs require accuracy and repeatability, while it is also necessary to accurately measure physical parameters such as pulse, heart rate, body temperature, and breathing rates. These features should be added in cases where they are not yet available. At present, the market for wearable devices is growing rapidly, and this will drive the further development of the technology to deliver the features and attributes demanded by users. This study has therefore addressed the fact that consumers need access to accurate and reliable information with regard to the latest gadgets available on the market and the performance of those devices.

### **Acknowledgements**

This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIP) (No. 2017M3A9C6029312).

### **Author details**

Kanitthika Kaewkannate and Soochan Kim\*

\*Address all correspondence to: sckim@hknu.ac.kr

Department of Electrical and Electronic Engineering, Hankyong National University, Anseong-si Gyeonggi-do, South Korea

### **References**

[1] Best Fitness Trackers. 2015: Jawbone, Misfit, Fitbit, Germin and More. Available on: http://www.wareable.com/fitness-trackers/the-best-fitness-tracker


Wearable technology can create a vividly realistic and immersive environment in real time. This concept is not new. Modern prototypes are moving away from bulky technology, such as large goggles and backpacks, toward smaller, lightweight, and more mobile systems.

On the author's viewpoint, the most comparable of the wearable device is that it cannot display itself but needs the smartphone to involve the metric data and reports. However, the storage of mobile phone to store and display the results is bigger, but it is inconvenient to use both at the same time. And yet, presently many fitness-tracking applications are available through the online store for free without any special or specific device. It is very convenience to whom that focuses in their healthy or fitness tracker. Even though the report of it is not guarantee 100% of accuracy, it is the easiest way to track their activity without any payment. Thus, the companies who produced the fitness tracker or wearable devices to the market in this highly competitive market will continuously develop new eye-catching products and reduce errors using the voices and opinions of users from this study to reach a wider market in the future. The relationship between technology and esthetics must go together, such as unobtrusive design, very sleek and modern and light weight, waterproof function, and many choices to recharge batteries. Basic activities such as walking or climbing stairs require accuracy and repeatability, while it is also necessary to accurately measure physical parameters such as pulse, heart rate, body temperature, and breathing rates. These features should be added in cases where they are not yet available. At present, the market for wearable devices is growing rapidly, and this will drive the further development of the technology to deliver the features and attributes demanded by users. This study has therefore addressed the fact that consumers need access to accurate and reliable information with regard to the latest gadgets available on the market and the perfor-

This work was supported by the National Research Foundation of Korea(NRF) grant funded

Department of Electrical and Electronic Engineering, Hankyong National University,

http://www.wareable.com/fitness-trackers/the-best-fitness-tracker

[1] Best Fitness Trackers. 2015: Jawbone, Misfit, Fitbit, Germin and More. Available on:

by the Korea government(MSIP) (No. 2017M3A9C6029312).

Kanitthika Kaewkannate and Soochan Kim\*

Anseong-si Gyeonggi-do, South Korea

\*Address all correspondence to: sckim@hknu.ac.kr

mance of those devices.

216 Wearable Technologies

**Acknowledgements**

**Author details**

**References**


[21] Fitbit Flex Wireless Activity Review. Available on: http://www.smartactivitytracker.net/ fitbit-flex

**Chapter 11**

Provisional chapter

**Bio-Inspired Wearable Antennas**

Bio-Inspired Wearable Antennas

Paulo Fernandes da Silva Júnior, Alexandre Jean René Serres, Raimundo Carlos Silvério Freire, Georgina Karla de Freitas Serres,

Paulo Fernandes da Silva Júnior, Alexandre Jean René Serres, Raimundo Carlos Silvério Freire, Georgina Karla de Freitas Serres,

Joabson Nogueira de Carvalho and Ewaldo Eder Carvalho Santana

Joabson Nogueira de Carvalho and Ewaldo Eder Carvalho Santana

http://dx.doi.org/10.5772/intechopen.75912

Additional information is available at the end of the chapter

wireless local area network (2.4 and 5 GHz) protocols.

Due to the recent miniaturization of wireless devices, the use of wearable antennas is steadily increasing. A wearable antenna is intended to be a part of the clothing used for communication purposes. In this way, a lower visual cost may be achieved. Recently, biologically inspired design, a kind of design by cross-domain analogy is a promising paradigm for innovation as well as low visual cost. The shapes of the plants are structures optimized by nature with the primary goal of light energy capture, transforming it into chemical energy. In this case, they have similar behavior to that of parabolic reflectors; this enables microwave engineers design innovative antennas using bio-inspired concepts. One of the advantages of using bio-inspired plant shapes is the design of antennas with great perimeters in compact structures. Thus, we have small antennas operating in low frequencies. This chapter presents the recent development in bio-inspired wearable antennas, easily integrated to the clothes and accessories used by the body, built in denim, low-cost flexible dielectric, and polyamide flexible dielectric, that is flexible with high resistance to twists and temperatures, for wireless body area network (WBAN) applications, operating in cellular mobile (2G, 3G, and 4G) and

DOI: 10.5772/intechopen.75912

Keywords: wearable flexible antenna, bio-inspired plant shape, wireless body area

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Additional information is available at the end of the chapter

Edmar Candeia Gurjão,

Edmar Candeia Gurjão,

Abstract

network


#### **Chapter 11** Provisional chapter

#### **Bio-Inspired Wearable Antennas** Bio-Inspired Wearable Antennas

Paulo Fernandes da Silva Júnior, Alexandre Jean René Serres, Raimundo Carlos Silvério Freire, Georgina Karla de Freitas Serres, Edmar Candeia Gurjão, Joabson Nogueira de Carvalho and Ewaldo Eder Carvalho Santana Paulo Fernandes da Silva Júnior, Alexandre Jean René Serres, Raimundo Carlos Silvério Freire, Georgina Karla de Freitas Serres, Edmar Candeia Gurjão, Joabson Nogueira de Carvalho and Ewaldo Eder Carvalho Santana

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.75912

#### Abstract

[21] Fitbit Flex Wireless Activity Review. Available on: http://www.smartactivitytracker.net/

[22] Fitbit Flex Review. Available on: http://health.thefuntimesguide.com/2014/09/fitbit-flex.

[23] Fitbit Flex. Available on: http://fitness-trackers-review.toptenreviews.com/fitbit-flex-

[24] Misfit Shine Activity Tracker Review. Available on: http://www.bestfitnesstrackerre-

[25] Misfit Shine. Available on: http://fitness-trackers-review.toptenreviews.com/shine-activ-

[26] Misfit Shine. Available on: http://pedometers-review.toptenreviews.com/misfit-shine-

[28] Review: Shine Activity Monitor". Available on: http://appleinsider.com/articles/13/11/13/

[27] Misfit Shine. Available on: http://www.pcmag.com/article2/0,2817,2423341,00.asp

fitbit-flex

review.html

review.html

views.com/misfit-shine-review.html

ity-tracker-review.html

review-shine-activity-monitor

php

218 Wearable Technologies

Due to the recent miniaturization of wireless devices, the use of wearable antennas is steadily increasing. A wearable antenna is intended to be a part of the clothing used for communication purposes. In this way, a lower visual cost may be achieved. Recently, biologically inspired design, a kind of design by cross-domain analogy is a promising paradigm for innovation as well as low visual cost. The shapes of the plants are structures optimized by nature with the primary goal of light energy capture, transforming it into chemical energy. In this case, they have similar behavior to that of parabolic reflectors; this enables microwave engineers design innovative antennas using bio-inspired concepts. One of the advantages of using bio-inspired plant shapes is the design of antennas with great perimeters in compact structures. Thus, we have small antennas operating in low frequencies. This chapter presents the recent development in bio-inspired wearable antennas, easily integrated to the clothes and accessories used by the body, built in denim, low-cost flexible dielectric, and polyamide flexible dielectric, that is flexible with high resistance to twists and temperatures, for wireless body area network (WBAN) applications, operating in cellular mobile (2G, 3G, and 4G) and wireless local area network (2.4 and 5 GHz) protocols.

DOI: 10.5772/intechopen.75912

Keywords: wearable flexible antenna, bio-inspired plant shape, wireless body area network

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

### 1. Introduction

Wireless body area network (WBAN) are sensor networks with elements located in the human body whose mobility and chemical composition impose challenges to wireless communication in such networks. Antennas are crucial elements for such communication and beyond the requirements of gain, directivity and others, for WBAN network wearable antennas as they are named have other important design requirements such as minimum destructive coupling between antenna and body, low visual impact, low-cost, flexible, and compact structure, ease of integration to the clothes and accessories used next to the body [1]. Its applications can be extended for continuous health and sports monitoring, safety, and security of people [2]. Research into development of wearable antennas has used several materials and shapes operating in different resonance frequencies [1–7].

shapes represent a great potential research field. Based on this characteristic, leaf shapes have been used as inspiration in the geometry of antennas via formulation projected to automatically reproduce such shapes as fractal geometry [10], the Fibonacci series, the Gold number

The formulation proposed by Johan Gielis in 2003 allows mathematically describing a wide variety of natural and abstract forms, such as leaf and flower shapes. Based on the concept of

and modifying Eq. (1) considering idea that many natural forms can be interpreted as modified circles, Gielis obtained what is called a superformula (Eq. (2)) by using polar coordinates, replacing x = r.cos(θ) and y = r.sin(θ) in addition to inserting the argument m/4 to create specific rotational symmetry in some structures, and the possibility of using different values of exponent

<sup>f</sup> <sup>¼</sup> <sup>f</sup>ð Þ <sup>θ</sup> <sup>1</sup> ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

From this expression, it is possible to generate and modify several shapes by the manipulation

This expression can also be combined with other functions, (θ), generating other forms. In order to illustrate the possibilities of the Gielis formula some example of shapes can be seen

In [11] the Gielis formula is used to generate various metamaterial unit cells with resonant frequencies in range of 6–8 GHz. In [5], a wearable textile printed monopole antenna is bioinspired in Gingko biloba leaf shape, generated by Gielis formula with bandwidth of 2.7 GHz,

Patch antennas using the Gielis formula were presented in [12], operating in cellular mobile and WLAN band, built in denim and fiber-glass (FR4). A parametrical analysis of bio-inspired leaf shape of jasmine flower, developed by Gielis formula, in printed monopole antennas with application in ultra-wide band, and X-band frequencies was presented in [13]. A transparent

� � � <sup>n</sup> <sup>n</sup><sup>3</sup> <sup>1</sup>

<sup>b</sup> sin θ <sup>m</sup> 4 � � � � �

<sup>q</sup> (2)

¼ 1 (1)

Bio-Inspired Wearable Antennas

221

http://dx.doi.org/10.5772/intechopen.75912

x a � � � � � � � � n þ x b � � � � � � n

1 <sup>a</sup> cos θ <sup>m</sup> 4 � � � � � � � �<sup>n</sup><sup>2</sup> <sup>1</sup>

[10], and the Gielis formula [8].

superellipses given by.

n for each term (n1, n2, n3).

of the six parameters (a, b, m, n1, n2, n3).

with the respective parameters in Figure 1.

Figure 1. Shapes generated by Gielis formula with the respective parameters.

operating in 2G, 3G, and 4G bands.

Evolution has permitted animals and natural structures to adjust their behavior and formats to obtain optimum performance in various aspects. Engineering has observed and applied such aspects to solve problems. Examples are genetic algorithms and ant colony optimization. Natural plant leaves present similar characteristics to fractals, as, for example, reduction of dimensions with perimeter increase and also that they have complex and efficient light harvesting-reaction center, that is, an array of antennas capable of operating in the visible light range (400–700 nm) with characteristics analogous to satellite dishes.

The leaves characteristics are well suited to antenna design, including the ones for wearable antennas and this bio-inspiration (leaf-shaped antennas) open a vast research field for more compact and efficient antennas. In this chapter, we use a polar expression developed to represent the geometry of plants and other living beings known as Gielis formula [8] to design wearable antennas operating in cellular mobile systems and WBAN. Antennas were developed for various plant shapes and different substrates, and their superior performance compared to classical antennas developed to the same application is clear.

Projects of the bio-inspired wearable antennas were realized with patch and monopole antennas, built in denim and polyamide, with shapes generated by Gielis formula, for WBAN application operating in WLAN (2.4–2.4835 and 5.4–5.85 GHz), 2G (1.8–2.1 GHz), 3G (1.885– 2.17 GHz), and 4G (2.5–2.69 GHz) bands.

### 2. Bio-inspired antenna design

#### 2.1. Gielis formula

In plants, the process of photosynthesis uses visible light (electromagnetic waves) to produce chemical energy. The leaves have two sections for processing the light, the complex capture centers and the reaction centers. The complex capture centers are formed by an arrangement to perform the highest light energy capture [9]. Thus the leaves act as receiving electromagnetic wave antennas with similar structure to parabolic reflectors, formats of the leaves evolved to give the optimum performance in terms of energy capture; thus for antennas design plants shapes represent a great potential research field. Based on this characteristic, leaf shapes have been used as inspiration in the geometry of antennas via formulation projected to automatically reproduce such shapes as fractal geometry [10], the Fibonacci series, the Gold number [10], and the Gielis formula [8].

1. Introduction

220 Wearable Technologies

ating in different resonance frequencies [1–7].

with characteristics analogous to satellite dishes.

antennas developed to the same application is clear.

2.17 GHz), and 4G (2.5–2.69 GHz) bands.

2. Bio-inspired antenna design

2.1. Gielis formula

Wireless body area network (WBAN) are sensor networks with elements located in the human body whose mobility and chemical composition impose challenges to wireless communication in such networks. Antennas are crucial elements for such communication and beyond the requirements of gain, directivity and others, for WBAN network wearable antennas as they are named have other important design requirements such as minimum destructive coupling between antenna and body, low visual impact, low-cost, flexible, and compact structure, ease of integration to the clothes and accessories used next to the body [1]. Its applications can be extended for continuous health and sports monitoring, safety, and security of people [2]. Research into development of wearable antennas has used several materials and shapes oper-

Evolution has permitted animals and natural structures to adjust their behavior and formats to obtain optimum performance in various aspects. Engineering has observed and applied such aspects to solve problems. Examples are genetic algorithms and ant colony optimization. Natural plant leaves present similar characteristics to fractals, as, for example, reduction of dimensions with perimeter increase and also that they have complex and efficient light harvesting-reaction center, that is, an array of antennas capable of operating in the visible light range (400–700 nm)

The leaves characteristics are well suited to antenna design, including the ones for wearable antennas and this bio-inspiration (leaf-shaped antennas) open a vast research field for more compact and efficient antennas. In this chapter, we use a polar expression developed to represent the geometry of plants and other living beings known as Gielis formula [8] to design wearable antennas operating in cellular mobile systems and WBAN. Antennas were developed for various plant shapes and different substrates, and their superior performance compared to classical

Projects of the bio-inspired wearable antennas were realized with patch and monopole antennas, built in denim and polyamide, with shapes generated by Gielis formula, for WBAN application operating in WLAN (2.4–2.4835 and 5.4–5.85 GHz), 2G (1.8–2.1 GHz), 3G (1.885–

In plants, the process of photosynthesis uses visible light (electromagnetic waves) to produce chemical energy. The leaves have two sections for processing the light, the complex capture centers and the reaction centers. The complex capture centers are formed by an arrangement to perform the highest light energy capture [9]. Thus the leaves act as receiving electromagnetic wave antennas with similar structure to parabolic reflectors, formats of the leaves evolved to give the optimum performance in terms of energy capture; thus for antennas design plants The formulation proposed by Johan Gielis in 2003 allows mathematically describing a wide variety of natural and abstract forms, such as leaf and flower shapes. Based on the concept of superellipses given by.

$$\left|\frac{\mathbf{x}}{\mathbf{a}}\right|^n + \left|\frac{\mathbf{x}}{\mathbf{b}}\right|^n = 1 \tag{1}$$

and modifying Eq. (1) considering idea that many natural forms can be interpreted as modified circles, Gielis obtained what is called a superformula (Eq. (2)) by using polar coordinates, replacing x = r.cos(θ) and y = r.sin(θ) in addition to inserting the argument m/4 to create specific rotational symmetry in some structures, and the possibility of using different values of exponent n for each term (n1, n2, n3).

$$f = f(\theta) \frac{1}{\sqrt[n]{\left( \left| \frac{1}{a} \cos \left( \theta \frac{m}{4} \right) \right| \right)^{n\_2} \left( \left| \frac{1}{b} \sin \left( \theta \frac{m}{4} \right) \right| \right)^{n\_3}}} \tag{2}$$

From this expression, it is possible to generate and modify several shapes by the manipulation of the six parameters (a, b, m, n1, n2, n3).

This expression can also be combined with other functions, (θ), generating other forms. In order to illustrate the possibilities of the Gielis formula some example of shapes can be seen with the respective parameters in Figure 1.

In [11] the Gielis formula is used to generate various metamaterial unit cells with resonant frequencies in range of 6–8 GHz. In [5], a wearable textile printed monopole antenna is bioinspired in Gingko biloba leaf shape, generated by Gielis formula with bandwidth of 2.7 GHz, operating in 2G, 3G, and 4G bands.

Patch antennas using the Gielis formula were presented in [12], operating in cellular mobile and WLAN band, built in denim and fiber-glass (FR4). A parametrical analysis of bio-inspired leaf shape of jasmine flower, developed by Gielis formula, in printed monopole antennas with application in ultra-wide band, and X-band frequencies was presented in [13]. A transparent

Figure 1. Shapes generated by Gielis formula with the respective parameters.

patch antenna operating in WLAN 5G, with bio-inspired plant shape of Inga edulis mart was performed in [14].

In the choice of structure with composite sheets we must consider the perimeter identified in the design of the antenna with Euclidean geometry. The objective is to obtain a bio-inspired

Bio-Inspired Wearable Antennas

223

http://dx.doi.org/10.5772/intechopen.75912

Microstrip patch antennas and monopole antennas are a well-known concept. In the following sections the formulation of bio-inspired shapes using the Gielis formula and the electrical

Researches in wearable antennas cover medical and non-medical applications, operating in several frequency ranges, and built on various substrates [2, 18–21]. For the development of wearable antennas and other electromagnetic wearable devices, it is crucial to know the electrical characteristics of the flexible substrate used. The objective is to identify the relative permittivity and the loss tangent of the materials. According to [22], the main methods employed to characterize dielectric materials are: coaxial probe, transmission line, free space, resonant cavity, and

The measurement of the flexible materials performed with coaxial probe method is the more popular technique to measure complex dielectric permittivity of many materials. This method is non-destructive, broadband and measurements at high-temperature can be performed with

In this chapter, design of wearable bio-inspired antennas used two flexible substrates, namely

Research presented antennas and other devices in textile substrate with applications in different frequency bands. In [23], the performance of textile antenna under two-dimensional crumpling conditions for 2.45 and 5.8 GHz is shown. In [6], a shielded stripline made in textile materials is designed as wearable flexible transmission line for broadband operation until 8 GHz. Denim is porous material with planar structure whose properties are determined by its fiber arrangement, density, volume, and size. Jeans is a fabric of denim that is very thin with

Polyamide laminate is flexible material with thermal and mechanical resistance characteristics, which has possibility of used in development of the devices for monitoring in situations of high-temperature risks such as monitoring the level of blood oxygenation and cardiac beats in firefighters and workers of metal machining centers. A wearable rectangular patch antenna for medical body area network (MBAN) (2.36–2.4 GHz) built in polyamide was presented in [24]. The dielectric substrates were characterized in the Laboratory of Measurements of the Federal Institute of Paraíba (IFPB), Campus of João Pessoa using a Vector Network Analyzer (VNA) of Agilent model S5071C (300 kHz–20 GHz) and the Dielectric Probe Kit 85070 of Agilent. Figure 2 shows the electrical characterization measurement setup of the flexible dielectrics

Figure 3 shows dielectric characterization, permittivity and loss tangent, of polyamide and denim substrates. The denim substrate was characterized with ε<sup>r</sup> = 2.03, loss tangent of 0.2, and

characterization of wearable materials employed to design the antennas are presented.

structure with total perimeter closest to the antenna with Euclidean geometry.

2.3. Electrical characterization of wearable substrate

a commercial instrumentation easily available.

used to design wearable antennas, polyamide and denim.

the denim and the polyamide.

a planar dielectric structure.

parallel plates.

#### 2.2. Procedure to design antenna via Gielis formula

Parameters of an antenna, such as resonance frequency, bandwidth, gain and radiation pattern are directly affected by the shape and materials used for its construction. Beyond such characteristics, wearable antennas should preferably have flexible structures for conductive material and dielectric substrate and must be as flat as possible [15]. In addition, characteristics of permittivity and thickness of dielectric substrate are crucial to determine the bandwidth and the antenna efficiency.

The design methodology of bio-inspired antennas in plants generated by the expression of Gielis was adapted from [16] for the design of wearable antennas, and consists of the following 11 steps:


In order to choose the shapes of the elliptical sheets, in step 7, it may observed that for the patch antenna design, the width of the sheet will follow the same principle of the design of microstrip transmission lines [16, 17]. Thus, the use of substrate with lower thickness (h) and higher relative electrical permittivity (εr) will imply the design of smaller width sheets.

For the design of planar monopole leaves having width greater than the length allows the development of antennas with greater bandwidth. The bio-inspired antennas presented in this chapter use symmetrical sheets structures, with the purpose of providing diagrams of broadside radiation, that is, with maximum gain in the axial direction to the axis of the antenna. Depending on the application, non-symmetrical structures can be used.

In the choice of structure with composite sheets we must consider the perimeter identified in the design of the antenna with Euclidean geometry. The objective is to obtain a bio-inspired structure with total perimeter closest to the antenna with Euclidean geometry.

Microstrip patch antennas and monopole antennas are a well-known concept. In the following sections the formulation of bio-inspired shapes using the Gielis formula and the electrical characterization of wearable materials employed to design the antennas are presented.

#### 2.3. Electrical characterization of wearable substrate

patch antenna operating in WLAN 5G, with bio-inspired plant shape of Inga edulis mart was

Parameters of an antenna, such as resonance frequency, bandwidth, gain and radiation pattern are directly affected by the shape and materials used for its construction. Beyond such characteristics, wearable antennas should preferably have flexible structures for conductive material and dielectric substrate and must be as flat as possible [15]. In addition, characteristics of permittivity and thickness of dielectric substrate are crucial to determine the bandwidth and the antenna efficiency. The design methodology of bio-inspired antennas in plants generated by the expression of Gielis was adapted from [16] for the design of wearable antennas, and consists of the following 11 steps:

3. Choice of antenna characteristics suitable for the application, broadband or narrowband,

5. Characterization of the properties of the materials, using the technical data informed by

6. Design of an antenna with Euclidean geometry (square, rectangular, or circular) in order to

7. Selection of the bio-inspired shape between elliptic leaves that have total perimeter closest

8. Generation of the image by the Gielis expression with the use of computer aided (CAD)

9. Simulation and optimization of the antenna characteristics, with adjustments to obtain the

In order to choose the shapes of the elliptical sheets, in step 7, it may observed that for the patch antenna design, the width of the sheet will follow the same principle of the design of microstrip transmission lines [16, 17]. Thus, the use of substrate with lower thickness (h) and

For the design of planar monopole leaves having width greater than the length allows the development of antennas with greater bandwidth. The bio-inspired antennas presented in this chapter use symmetrical sheets structures, with the purpose of providing diagrams of broadside radiation, that is, with maximum gain in the axial direction to the axis of the antenna. Depending

higher relative electrical permittivity (εr) will imply the design of smaller width sheets.

the manufacturers or using some available characterization method;

techniques in a format exportable to the full-wave simulation software;

11. Validation using measurement and comparison with simulated results.

performed in [14].

222 Wearable Technologies

1. Definition of the application;

2. Identification of operating frequencies;

type of polarization, among others;

obtain total perimeter of the structure;

to the antenna with Euclidean geometry;

desired resonance frequency;

10. Construction of the bio-inspired antenna;

on the application, non-symmetrical structures can be used.

4. Selection of the conductor and dielectric material;

2.2. Procedure to design antenna via Gielis formula

Researches in wearable antennas cover medical and non-medical applications, operating in several frequency ranges, and built on various substrates [2, 18–21]. For the development of wearable antennas and other electromagnetic wearable devices, it is crucial to know the electrical characteristics of the flexible substrate used. The objective is to identify the relative permittivity and the loss tangent of the materials. According to [22], the main methods employed to characterize dielectric materials are: coaxial probe, transmission line, free space, resonant cavity, and parallel plates.

The measurement of the flexible materials performed with coaxial probe method is the more popular technique to measure complex dielectric permittivity of many materials. This method is non-destructive, broadband and measurements at high-temperature can be performed with a commercial instrumentation easily available.

In this chapter, design of wearable bio-inspired antennas used two flexible substrates, namely the denim and the polyamide.

Research presented antennas and other devices in textile substrate with applications in different frequency bands. In [23], the performance of textile antenna under two-dimensional crumpling conditions for 2.45 and 5.8 GHz is shown. In [6], a shielded stripline made in textile materials is designed as wearable flexible transmission line for broadband operation until 8 GHz. Denim is porous material with planar structure whose properties are determined by its fiber arrangement, density, volume, and size. Jeans is a fabric of denim that is very thin with a planar dielectric structure.

Polyamide laminate is flexible material with thermal and mechanical resistance characteristics, which has possibility of used in development of the devices for monitoring in situations of high-temperature risks such as monitoring the level of blood oxygenation and cardiac beats in firefighters and workers of metal machining centers. A wearable rectangular patch antenna for medical body area network (MBAN) (2.36–2.4 GHz) built in polyamide was presented in [24].

The dielectric substrates were characterized in the Laboratory of Measurements of the Federal Institute of Paraíba (IFPB), Campus of João Pessoa using a Vector Network Analyzer (VNA) of Agilent model S5071C (300 kHz–20 GHz) and the Dielectric Probe Kit 85070 of Agilent. Figure 2 shows the electrical characterization measurement setup of the flexible dielectrics used to design wearable antennas, polyamide and denim.

Figure 3 shows dielectric characterization, permittivity and loss tangent, of polyamide and denim substrates. The denim substrate was characterized with ε<sup>r</sup> = 2.03, loss tangent of 0.2, and

Figure 2. Electrical characterization measurement setup: (a) polyamide; and (b) denim.

Figure 3. Electrical characterization: (a) denim; and (b) polyamide.

thickness of 1 mm and the polyamide substrate was characterized with ε<sup>r</sup> = 4, loss tangent of 0.04, and thickness of 0.05 mm.

#### 3. Bio-inspired wearable antennas

This section presents wearable bio-inspired antennas built in denim and polyamide operating in cellular mobile communication (2G, 3G, and 4G), and WLAN in 2.4 and 5 GHz applications. Figure 5 presents curves for the simulated and measured values of|S11| for the jasmine flower bio-inspired antenna parameters of wearable monopole antenna bio-inspired presented in Figure 4. In Figure 5, the frequency mask for 2G, 3G, 4G, and WLAN 2.4 and 5 GHz band are indicated. The mismatch between the simulated and measured results can be explained by the manufacture process of the antenna. However, a wider band at 10 dB can be observed with

Figure 5. |S11| curves for the simulated and measured (prototype) jasmine flower wearable monopole bio-inspired

Figure 4. Developed wearable textile monopole antenna bio-inspired in jasmine flower shape: (a) jasmine flower [25]; (b)

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simulated patch element; (c) simulate ground plane; prototype, front vision (d); prototype, back vision (e).

Considering that the projected antenna have to be wearable, it was necessary to perform measurements near the body, as also considering that in certain situations the antenna can be bent. Figure 6 presents some of the positions for the near body situations, namely on the hand, in the pocket, and on the chest of the prototype proposed. Figure 7 presents the |S11| curves in each configuration. For comparison, in Figure 7, the curve measured was obtained with the antenna in the free space, that is, with the minimum reflections in its neighborhood. It can be noticed when the antenna is close to the body its first resonance frequency modifies, and the highest variation compared to the Measured value (1.9 GHz) occurs with the antenna on the hand

the built antenna covering all of frequency bands.

antenna.

#### 3.1. Wearable bio-inspired antennas built in denim

#### 3.1.1. Wearable monopole antenna bio-inspired in jasmine flower shape

The jasmine flower presented in Figure 4(a) was the bio-inspiration for antennas operating in mobile cellular system (2G, 3G, and 4G). Figure 4(b) presents the simulated antenna and Figure 4(c) the simulated ground plane. Figure 4(d), (e) presents the implemented antenna front and back respectively. The shape of the jasmine flower was generated by the Gielis formula with value: m = 8, n1 = 40, n2 and n3 = 20, a and b = 1.

Figure 4. Developed wearable textile monopole antenna bio-inspired in jasmine flower shape: (a) jasmine flower [25]; (b) simulated patch element; (c) simulate ground plane; prototype, front vision (d); prototype, back vision (e).

Figure 5. |S11| curves for the simulated and measured (prototype) jasmine flower wearable monopole bio-inspired antenna.

thickness of 1 mm and the polyamide substrate was characterized with ε<sup>r</sup> = 4, loss tangent of

This section presents wearable bio-inspired antennas built in denim and polyamide operating in cellular mobile communication (2G, 3G, and 4G), and WLAN in 2.4 and 5 GHz applications.

The jasmine flower presented in Figure 4(a) was the bio-inspiration for antennas operating in mobile cellular system (2G, 3G, and 4G). Figure 4(b) presents the simulated antenna and Figure 4(c) the simulated ground plane. Figure 4(d), (e) presents the implemented antenna front and back respectively. The shape of the jasmine flower was generated by the Gielis

0.04, and thickness of 0.05 mm.

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3. Bio-inspired wearable antennas

3.1. Wearable bio-inspired antennas built in denim

Figure 3. Electrical characterization: (a) denim; and (b) polyamide.

3.1.1. Wearable monopole antenna bio-inspired in jasmine flower shape

Figure 2. Electrical characterization measurement setup: (a) polyamide; and (b) denim.

formula with value: m = 8, n1 = 40, n2 and n3 = 20, a and b = 1.

Figure 5 presents curves for the simulated and measured values of|S11| for the jasmine flower bio-inspired antenna parameters of wearable monopole antenna bio-inspired presented in Figure 4. In Figure 5, the frequency mask for 2G, 3G, 4G, and WLAN 2.4 and 5 GHz band are indicated. The mismatch between the simulated and measured results can be explained by the manufacture process of the antenna. However, a wider band at 10 dB can be observed with the built antenna covering all of frequency bands.

Considering that the projected antenna have to be wearable, it was necessary to perform measurements near the body, as also considering that in certain situations the antenna can be bent. Figure 6 presents some of the positions for the near body situations, namely on the hand, in the pocket, and on the chest of the prototype proposed. Figure 7 presents the |S11| curves in each configuration. For comparison, in Figure 7, the curve measured was obtained with the antenna in the free space, that is, with the minimum reflections in its neighborhood. It can be noticed when the antenna is close to the body its first resonance frequency modifies, and the highest variation compared to the Measured value (1.9 GHz) occurs with the antenna on the hand

Figure 6. Positions of measurement for the jasmine flower antenna: (a) free space(measured), (b) on the hand, (c) in the pocket, and (d) on the chest.

bending configuration and a greater bandwidth (5.21 GHz) is observed in the creased config-

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The different bending of the antenna generates a discontinuity of the current density on the radiating element, thus modifying its impedance. In spite of that, all the frequency bands are

In Table 1 are presented values for the first resonance frequency (f1), last resonance frequency (f2) in 10 dB, and bandwidth for the proposed wearable antenna for each configuration

Observing values in Table 1 we can notice that the Jasmine wearable antenna simulated, measured free and forward bending presents difference in first resonance frequency (f1), resonance of 35.26%, and smaller bandwidth of 14.77%. The most significant points are the five similar results, with bandwidth ranging from 4.4 to 4.87 GHz. Only two results are outside these limits, with a bandwidth below of 4 GHz and greater than 5 GHz. It can be observed a difference about 1 GHz between the backward and forward bending that is important infor-

Antenna f1 (GHz) f2 (GHz) Bandwidth (GHz)

Table 1. Measured and simulated values of resonant frequencies and bandwidth of the wearable bio-inspired antenna.

Simulated 1.42 4.20 2.78 Measured 1.90 6.57 4.67 On the hand 2.52 6.92 4.40 In the pocket 2.25 6.75 4.50 On the chest 2.25 6.85 4.60 Creased 1.94 7.15 5.21 Forward bending 2.57 6.55 3.98 Backward bending 2.01 6.88 4.87

covered except for the forward bending in low frequencies.

Figure 9. |S11| curves for bending positions of the jasmine flower wearable antenna.

mation for this kind of wearable antenna.

uration.

presented above.

Figure 7. |S11| curves for the simulated and measured (prototype) of the wearable antenna with body interference.

Figure 8. Position of measurement for bending the antenna: (a) free space, (b) creased, (c) forward bended, and (d) backward bended for the jasmine flower wearable antenna.

(2.52 GHz). The permittivity of the various parts of the body can be different according to the percent water and mainly modifying the resonance frequencies in the UHF band.

Another set of measurement considers that the antenna can be bent or even creased as occurs in clothes. Figure 8(a) presents the free space, Figure 8(b) creased, Figure 8c) forward bending, and Figure 8(d) backward bending positions. Figure 9 presents the measured |S11| values for each configuration. Again, the free space (Measured curve) is the reference and it can be noticed that the greatest difference in the first resonance frequency occurs in the forward

Figure 9. |S11| curves for bending positions of the jasmine flower wearable antenna.

bending configuration and a greater bandwidth (5.21 GHz) is observed in the creased configuration.

The different bending of the antenna generates a discontinuity of the current density on the radiating element, thus modifying its impedance. In spite of that, all the frequency bands are covered except for the forward bending in low frequencies.

In Table 1 are presented values for the first resonance frequency (f1), last resonance frequency (f2) in 10 dB, and bandwidth for the proposed wearable antenna for each configuration presented above.

Observing values in Table 1 we can notice that the Jasmine wearable antenna simulated, measured free and forward bending presents difference in first resonance frequency (f1), resonance of 35.26%, and smaller bandwidth of 14.77%. The most significant points are the five similar results, with bandwidth ranging from 4.4 to 4.87 GHz. Only two results are outside these limits, with a bandwidth below of 4 GHz and greater than 5 GHz. It can be observed a difference about 1 GHz between the backward and forward bending that is important information for this kind of wearable antenna.


(2.52 GHz). The permittivity of the various parts of the body can be different according to the

Figure 8. Position of measurement for bending the antenna: (a) free space, (b) creased, (c) forward bended, and (d)

Figure 7. |S11| curves for the simulated and measured (prototype) of the wearable antenna with body interference.

Figure 6. Positions of measurement for the jasmine flower antenna: (a) free space(measured), (b) on the hand, (c) in the

pocket, and (d) on the chest.

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Another set of measurement considers that the antenna can be bent or even creased as occurs in clothes. Figure 8(a) presents the free space, Figure 8(b) creased, Figure 8c) forward bending, and Figure 8(d) backward bending positions. Figure 9 presents the measured |S11| values for each configuration. Again, the free space (Measured curve) is the reference and it can be noticed that the greatest difference in the first resonance frequency occurs in the forward

percent water and mainly modifying the resonance frequencies in the UHF band.

backward bended for the jasmine flower wearable antenna.

Table 1. Measured and simulated values of resonant frequencies and bandwidth of the wearable bio-inspired antenna.

The 2D and 3D radiation patterns, gain, half power beamwidth (HPBW), and current density simulated at 3 and 1.6 GHz can be observed in Figure 10(a), (b). The results are according to the Federal Communications Commission (FCC) for a UWB antenna with a gain of 4.2 dBi at 3 GHz, omnidirectional pattern, and a HPBW greater than 75.

#### 3.1.2. Wearable antenna bio-inspired in Bidens pilosa plant shape

In Figure 11(a) is presented the Bidens pilosa plant that consists of a shape with three elliptical leaves, this format was used as the bio-inspiration for a narrowband wearable antenna that covers the WLAN range at 2.40 GHz (2.40–2.4835 GHz). Figure 11(b), (c) present the single leaf and the simulated antenna respectively, and Figure 11(d) the prototype antenna.

In the simulation and the prototype the under leaf was inclined at 20, and the down leaves were inclined at 40 in relation to the geometry of Bidens pilosa, in order to provide fine-tuning of the resonance frequency. From the Gielis formula, the leaves were generated with the parameters, n1 = 2, m = 400, n2 and n3 = 1200, a and b = 1. The final structure obtained total perimeter of 143.3 mm.

Figure 12 illustrates the measurements positions of the wearable antenna bio-inspired in Bidens

Figure 12. Measurement of prototype of the wearable textile antenna bio-inspired in Bidens pilosa plant shape: (a) free

Figure 11. Project of wearable antenna bio-inspired in Bidens pilosa plant shape: (a) Bidens pilosa leaf [26]; (b) single leaf

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Simulated and Measured |S11| curves for the wearable antenna proposed are presented in Figure 13(a). As it can be observed, the simulated and measured values present similar behavior. However the results present a difference of resonance frequency and bandwidth of 1.23% and 74.07%, respectively. The mismatch between the simulated and measured results can be explained by the manufacture process of the antenna and the dielectric permittivity variation of denim. Denim is a product used in the manufacture of clothing, that is, was not prepared by the factory to be used as a dielectric substrate in the construction of antennas. Difference in tenths of the dielectric permittivity may contribute to variations in MHz in the

Figure 13(b) presents the measured |S11| curves to each configuration illustrated in Figure 12. The greatest difference for resonance frequency and bandwidth (14.28%) appears with the wearable antenna on the hand, but still fully covering the WLAN band. The different bending of the antenna generates a discontinuity of the current density on the radiating element thus modifying its impedance and return loss. The greater difference is observed with the antenna

Values of bandwidth (BW), resonance frequency (f0), first (f1) and last (f2) resonance at 10 dB are presented in Table 2. The mismatch between the measured and simulated results can be explained by the rudimentary manufacture process. However, all measured results are coherent and demonstrate a certain immunity of the antenna when creased, bent, or close to the

close to the hand with the modification of the ground plane characteristic.

pilosa plant shape in anechoic chamber.

space; (b) creased; (c) bended; (d) on the hand.

with inclination; (c) simulated antenna; (d) prototype.

resonant frequency.

Figure 10. 3D and 2D radiation pattern of wearable textile monopole antenna bio-inspired in jasmine flower shape: (a) 3 GHz; and (b) 1.6 GHz.

The 2D and 3D radiation patterns, gain, half power beamwidth (HPBW), and current density simulated at 3 and 1.6 GHz can be observed in Figure 10(a), (b). The results are according to the Federal Communications Commission (FCC) for a UWB antenna with a gain of 4.2 dBi at

In Figure 11(a) is presented the Bidens pilosa plant that consists of a shape with three elliptical leaves, this format was used as the bio-inspiration for a narrowband wearable antenna that covers the WLAN range at 2.40 GHz (2.40–2.4835 GHz). Figure 11(b), (c) present the single leaf

In the simulation and the prototype the under leaf was inclined at 20, and the down leaves were inclined at 40 in relation to the geometry of Bidens pilosa, in order to provide fine-tuning of the resonance frequency. From the Gielis formula, the leaves were generated with the parameters, n1 = 2, m = 400, n2 and n3 = 1200, a and b = 1. The final structure obtained total

Figure 10. 3D and 2D radiation pattern of wearable textile monopole antenna bio-inspired in jasmine flower shape: (a)

and the simulated antenna respectively, and Figure 11(d) the prototype antenna.

3 GHz, omnidirectional pattern, and a HPBW greater than 75.

3.1.2. Wearable antenna bio-inspired in Bidens pilosa plant shape

perimeter of 143.3 mm.

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3 GHz; and (b) 1.6 GHz.

Figure 11. Project of wearable antenna bio-inspired in Bidens pilosa plant shape: (a) Bidens pilosa leaf [26]; (b) single leaf with inclination; (c) simulated antenna; (d) prototype.

Figure 12. Measurement of prototype of the wearable textile antenna bio-inspired in Bidens pilosa plant shape: (a) free space; (b) creased; (c) bended; (d) on the hand.

Figure 12 illustrates the measurements positions of the wearable antenna bio-inspired in Bidens pilosa plant shape in anechoic chamber.

Simulated and Measured |S11| curves for the wearable antenna proposed are presented in Figure 13(a). As it can be observed, the simulated and measured values present similar behavior. However the results present a difference of resonance frequency and bandwidth of 1.23% and 74.07%, respectively. The mismatch between the simulated and measured results can be explained by the manufacture process of the antenna and the dielectric permittivity variation of denim. Denim is a product used in the manufacture of clothing, that is, was not prepared by the factory to be used as a dielectric substrate in the construction of antennas. Difference in tenths of the dielectric permittivity may contribute to variations in MHz in the resonant frequency.

Figure 13(b) presents the measured |S11| curves to each configuration illustrated in Figure 12. The greatest difference for resonance frequency and bandwidth (14.28%) appears with the wearable antenna on the hand, but still fully covering the WLAN band. The different bending of the antenna generates a discontinuity of the current density on the radiating element thus modifying its impedance and return loss. The greater difference is observed with the antenna close to the hand with the modification of the ground plane characteristic.

Values of bandwidth (BW), resonance frequency (f0), first (f1) and last (f2) resonance at 10 dB are presented in Table 2. The mismatch between the measured and simulated results can be explained by the rudimentary manufacture process. However, all measured results are coherent and demonstrate a certain immunity of the antenna when creased, bent, or close to the

Figure 13. Comparison of |S11| parameters of wearable textile antenna bio-inspired in Bidens pilosa plant shape: (a) simulated and measured; (b) creased, bended and on the hand.

3.2. Wearable bio-inspired antennas built in polyamide

the center of the structure.

observed for the single leaf antenna at 5.8 GHz.

ence in first resonance less than 1.01%, Table 3.

In this section, Gielis formula is used in the design of a wearable flexible antenna array bioinspired in Inga maritimus plant shape, and it is designed both one leaf for 5.4 and 5.8 GHz, and

Figure 14. Radiation pattern of wearable textile antenna bio-inspired in Bidens pilosa plant shape [27]: (a) 3D; (b) 2D.

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Figure 15 shows the leaves of Inga maritimus, the single elliptical leaf for 5.4 and 5.8 GHz, the dimensions of the antenna arrays with two and four leaves and the prototypes built in polyamide. The single leaf was generated by Gielis formula, with parameters: m = 2, n1 = 20; n2 and n3 = 12, a and b = 1. To prevent mutual coupling between the radiating elements, a distance of one effective wavelength between the leaves was used. Position of leaves in the patch antenna array with four elements has been inverted, thus the radiation pattern stays in

Figure 16 shows the curves for simulated and measured |S11| curves for wearable antenna bio-inspired in Inga maritimus plant shape with one leaf, with the indication in dashed lines of wireless local area network (WLAN) band in 5 GHz (5.15–5.85 GHz). As observed, the single leaf shape antennas cover part of the WLAN band. The greater difference in resonance frequency (3.85%) was observed for the single leaf antenna at 5.4 GHz, and bandwidth 57.8% was

Figure 17(a) shows the simulated and measured |S11| curves of the wearable bio-inspired antenna arrays with two elements and four elements in Figure 17(b). The greater difference in bandwidth (52.39%) was observed for the wearable antenna with two elements, with differ-

The differences between the measured and simulated results of antennas and antenna arrays in polyamide can be the result of the variation in the dielectric properties of the material, and of the manufacture process. As the transmission lines are very thin, and the bio-inspired antennas

two patch antenna arrays with two and four leaves covering the WLAN 5 GHz band.

3.2.1. Wearable antenna arrays bio-inspired in Inga maritimus plant shape


Table 2. Values for resonance frequency and bandwidth for the wearable textile antenna bio-inspired in Bidens pilosa plant shape.

body with 60, 0, and 90 MHz of difference compared to the free space measurement, respectively.

Figure 14 shows the 2D and 3D radiation patterns of the wearable antenna bio-inspired proposed. The maximum current density observed was 48.06 A/m<sup>2</sup> at 2.42 GHz, with gain of 6.73 dBi, HPBW of 92, and relative front-to-back (F/B) of 25 dB. It can be noted than the radiation pattern measured and simulated presented similar behavior indicating good relationship between results. A higher concentration of current density in a smaller physical area is a characteristic of the bio-inspired antenna.

Figure 14. Radiation pattern of wearable textile antenna bio-inspired in Bidens pilosa plant shape [27]: (a) 3D; (b) 2D.

#### 3.2. Wearable bio-inspired antennas built in polyamide

body with 60, 0, and 90 MHz of difference compared to the free space measurement, respec-

Table 2. Values for resonance frequency and bandwidth for the wearable textile antenna bio-inspired in Bidens pilosa

Figure 13. Comparison of |S11| parameters of wearable textile antenna bio-inspired in Bidens pilosa plant shape: (a)

Antenna f0 (GHz) f1 (GHz) f2 (GHz) BW (GHz) Simulated 2.43 2.35 2.49 0.14 Measured 2.40 2.19 2.73 0.54 Measured creased 2.43 2.22 2.82 0.60 Measured bended 2.44 2.28 2.82 0.54 Measured on the hand 2.50 2.28 2.91 0.63

Figure 14 shows the 2D and 3D radiation patterns of the wearable antenna bio-inspired proposed. The maximum current density observed was 48.06 A/m<sup>2</sup> at 2.42 GHz, with gain of 6.73 dBi, HPBW of 92, and relative front-to-back (F/B) of 25 dB. It can be noted than the radiation pattern measured and simulated presented similar behavior indicating good relationship between results. A higher concentration of current density in a smaller physical area is

tively.

plant shape.

230 Wearable Technologies

a characteristic of the bio-inspired antenna.

simulated and measured; (b) creased, bended and on the hand.

In this section, Gielis formula is used in the design of a wearable flexible antenna array bioinspired in Inga maritimus plant shape, and it is designed both one leaf for 5.4 and 5.8 GHz, and two patch antenna arrays with two and four leaves covering the WLAN 5 GHz band.

#### 3.2.1. Wearable antenna arrays bio-inspired in Inga maritimus plant shape

Figure 15 shows the leaves of Inga maritimus, the single elliptical leaf for 5.4 and 5.8 GHz, the dimensions of the antenna arrays with two and four leaves and the prototypes built in polyamide. The single leaf was generated by Gielis formula, with parameters: m = 2, n1 = 20; n2 and n3 = 12, a and b = 1. To prevent mutual coupling between the radiating elements, a distance of one effective wavelength between the leaves was used. Position of leaves in the patch antenna array with four elements has been inverted, thus the radiation pattern stays in the center of the structure.

Figure 16 shows the curves for simulated and measured |S11| curves for wearable antenna bio-inspired in Inga maritimus plant shape with one leaf, with the indication in dashed lines of wireless local area network (WLAN) band in 5 GHz (5.15–5.85 GHz). As observed, the single leaf shape antennas cover part of the WLAN band. The greater difference in resonance frequency (3.85%) was observed for the single leaf antenna at 5.4 GHz, and bandwidth 57.8% was observed for the single leaf antenna at 5.8 GHz.

Figure 17(a) shows the simulated and measured |S11| curves of the wearable bio-inspired antenna arrays with two elements and four elements in Figure 17(b). The greater difference in bandwidth (52.39%) was observed for the wearable antenna with two elements, with difference in first resonance less than 1.01%, Table 3.

The differences between the measured and simulated results of antennas and antenna arrays in polyamide can be the result of the variation in the dielectric properties of the material, and of the manufacture process. As the transmission lines are very thin, and the bio-inspired antennas

Figure 15. Project of wearable antenna arrays bio-inspired in Inga maritimus plant shape: (a) Inga maritimus leaves [28]; (b) prototype for 5.4 GHz; (c) prototype for 5.8 GHz; (d) prototype antenna array with two leaves; (e) prototype antenna array with four leaves.

Figure 16. Simulated and measured |S11| parameter of wearable antenna bio-inspired in Inga maritimus plant shape: (a) 5.4 GHz; (b) 5.8 GHz.

in the Inga maratimus plant shape are compact and have sharp cuts, small variations in the built structure can cause significant variations in resonant frequencies and bandwidth, which can be numerically observed in Table 3. Even with the differences observed, the results indicate that the antennas presented antenna array characteristics, with increased gain (by increasing metal), and bandwidth, covering the frequency band indicated for WLAN technology at 5 GHz, indicating than there are possibility of using this type of antennas and substrate

Table 3. Frequency responses of wearable antenna arrays bio-inspired in Inga maritimus plant shape.

Figure 17. Comparison of simulated and measured |S11| parameters of wearable antenna arrays bio-inspired in Inga

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Antenna f0 (GHz) f1 (GHz) f2 (GHz) BW (GHz) RL (dB) Simulated 5.4 GHz 5.45 5.27 5.62 0.35 34.63 Measured 5.4 GHz 5.24 4.93 5.68 0.75 47.25 Simulated 5.8 GHz 5.83 5.74 5.93 0.19 24.62 Measured 5.8 GHz 5.94 5.7 6.15 0.45 28.54 Simulated Array 2 5.24/5.61 5.12 5.75 0.63 26.39 Measured Array 2 5.54 5.37 5.67 0.3 27.94 Simulated Array 4 4.94/5.48 4.78 5.82 1.04 34.6/28.8 Measured Array 4 4.89/5.38 4.53 6.52 1.99 23.51/41.91

maritimus plant shape: (a) antenna array with two leaves; (b) antenna array with four leaves.

Figure 17. Comparison of simulated and measured |S11| parameters of wearable antenna arrays bio-inspired in Inga maritimus plant shape: (a) antenna array with two leaves; (b) antenna array with four leaves.

Figure 15. Project of wearable antenna arrays bio-inspired in Inga maritimus plant shape: (a) Inga maritimus leaves [28]; (b) prototype for 5.4 GHz; (c) prototype for 5.8 GHz; (d) prototype antenna array with two leaves; (e) prototype antenna

Figure 16. Simulated and measured |S11| parameter of wearable antenna bio-inspired in Inga maritimus plant shape: (a)

array with four leaves.

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5.4 GHz; (b) 5.8 GHz.


Table 3. Frequency responses of wearable antenna arrays bio-inspired in Inga maritimus plant shape.

in the Inga maratimus plant shape are compact and have sharp cuts, small variations in the built structure can cause significant variations in resonant frequencies and bandwidth, which can be numerically observed in Table 3. Even with the differences observed, the results indicate that the antennas presented antenna array characteristics, with increased gain (by increasing metal), and bandwidth, covering the frequency band indicated for WLAN technology at 5 GHz, indicating than there are possibility of using this type of antennas and substrate

polyamide). Designed antennas were analyzed by simulation and by measurement in implemented prototypes. The proposed bio-inspiration results in more compact antennas by the reduction of the antennas radiating element. However, compared to Euclidean shapes, two side effects were observed a reduction of the gain and an increase of the current density. On the other hand, the bio-inspired antennas present a higher concentration of the surface current and the decrease of gain can be prevented using leaf arrays with esthetic appeal. The gain can be improved by using thicker substrates and the current density can be regulated using plant shapes with flat geometries or the least sharp possible. These characteristics open a large

\*, Alexandre Jean René Serres<sup>1</sup>

1 Electrical Engineering – COPELE, Federal University of Campina Grande – UFCG, Campina

[1] Gupta NP, Maheshwari R, Kumar M. Advanced in ultra wideband antennas for wearable applications. International Journal of Scientific & Engineering Research. 2013;4:341-348 [2] Shafique K, Khawaja BA, Tarar MA, Khan BM, Mustaqim M, Raza A. A wearable ultrawideband antenna for wireless body area networks. Microwave and Optical Technology

[3] Baroni A, Nepa P, Rogier H. Wearable self-tuning antenna for emergy rescue operations. IET Microwaves, Antennas and Propagation. 2016;10:173-183. DOI: 10.1049/iet-map.2015.0315 [4] Cavalcante GA, Minervino DR, D'Assunção AG, D'Assunção AG. A compact multiband reject inverted double-E microstrip filter on textile substrate. Microwave and Optical

[5] Silva Júnior PF, Silva PHF, Serres AJR, Freire RCS. Bio-inspired design of directional leafshaped printed monopole antennas for 4G 700 MHz band. Microwave and Optical Tech-

[6] Xu A, Feumeaux C. Wearable textile shielded strapline for broadband operation. IEEE Microwave and Wireless Components Letters. 2014;24:566-568. DOI: 10.1109/LMWC.2014.2321060

2 Electrical Engineering – PPGEE, Federal Institute of Paraiba – IFPB, João Pessoa, Brazil

, Georgina Karla de Freitas Serres<sup>1</sup>

,

, Edmar Candeia Gurjão<sup>1</sup>

Bio-Inspired Wearable Antennas

http://dx.doi.org/10.5772/intechopen.75912

,

235

research field for wearable embedded antennas.

3 State University of Maranhão, São Luis, Brazil

Joabson Nogueira de Carvalho<sup>2</sup> and Ewaldo Eder Carvalho Santana<sup>3</sup>

\*Address all correspondence to: paulo.junior@ee.ufcg.edu.br

Letters. 2016;58:1710-1715. DOI: 10.1002/mop.29888

Technology Letters. 2015;57:2543-2548. DOI: 10.1002/mop.29370

nology Letters. 2016;58:1529-1533. DOI: 10.1002/mop.29853

Author details

Grande, Brazil

References

Paulo Fernandes da Silva Júnior1

Raimundo Carlos Silvério Freire<sup>1</sup>

Figure 18. 3D and 2D radiation pattern of wearable antenna arrays bio-inspired in Inga maritimus plant shape: (a) 5.4 GHz; (b) 5.8 GHz; (c) antenna array with two leaves; (d) antenna array with four leaves.

in an environment that requires components resistant to the high temperature. In Table 3, the measured and simulated values, resonant frequencies at 10 dB, bandwidth (BW), return loss (RL), can be observed of each structure presented.

Figure 18 shows the 2D and 3D radiation patterns at respective resonance frequencies, with indication of gain, front-to-back (F/B) relation, half power beamwidth (HPBW), and current density of simulated wearable antennas bio-inspired in Inga maritimus plant shape. As observed, the use of bio-inspired leaf shape on the antenna array permits an increase in both bandwidth and gain. In comparison with wearable bio-inspired antenna with single leaf shape, wearable antenna arrays bio-inspired in Inga maritimus plant shape with four leaves presented gain 2.25 dBi greater than antenna array with two leaves, and 3.96 dBi greater than antenna with single leaf shape. From the radiation patterns of the bio-inspired antenna array with four elements, a lower HPBW (77) can be observed, which indicates a higher concentration of radiated energy, added to the highest gain (9.76 dBi), and a higher front-to-back ratio (23 dB), this indicates that the arrangement can be used for communication of greater distances or with less signal intensity.

#### 4. Conclusion

Wearable wireless systems impose new challenges to antenna design since the utilization in clothes, the proximity of the human body, and the possibility of format variations as bending implies in parameters like good esthetical appearance, low cost, integration to the clothes and accessories used next to the body, among others related to the wear like use of the antenna. In this chapter, we presented some trends for design innovative wearable bio-inspired antennas using plant leaves as inspiration parameterized by the Gielis formula to design antennas, and also we characterize different wearable flexible and low-cost dielectric materials (denim and polyamide). Designed antennas were analyzed by simulation and by measurement in implemented prototypes. The proposed bio-inspiration results in more compact antennas by the reduction of the antennas radiating element. However, compared to Euclidean shapes, two side effects were observed a reduction of the gain and an increase of the current density. On the other hand, the bio-inspired antennas present a higher concentration of the surface current and the decrease of gain can be prevented using leaf arrays with esthetic appeal. The gain can be improved by using thicker substrates and the current density can be regulated using plant shapes with flat geometries or the least sharp possible. These characteristics open a large research field for wearable embedded antennas.

### Author details

Paulo Fernandes da Silva Júnior1 \*, Alexandre Jean René Serres<sup>1</sup> , Raimundo Carlos Silvério Freire<sup>1</sup> , Georgina Karla de Freitas Serres<sup>1</sup> , Edmar Candeia Gurjão<sup>1</sup> , Joabson Nogueira de Carvalho<sup>2</sup> and Ewaldo Eder Carvalho Santana<sup>3</sup>

\*Address all correspondence to: paulo.junior@ee.ufcg.edu.br

1 Electrical Engineering – COPELE, Federal University of Campina Grande – UFCG, Campina Grande, Brazil


### References

in an environment that requires components resistant to the high temperature. In Table 3, the measured and simulated values, resonant frequencies at 10 dB, bandwidth (BW), return loss

Figure 18. 3D and 2D radiation pattern of wearable antenna arrays bio-inspired in Inga maritimus plant shape: (a)

5.4 GHz; (b) 5.8 GHz; (c) antenna array with two leaves; (d) antenna array with four leaves.

Figure 18 shows the 2D and 3D radiation patterns at respective resonance frequencies, with indication of gain, front-to-back (F/B) relation, half power beamwidth (HPBW), and current density of simulated wearable antennas bio-inspired in Inga maritimus plant shape. As observed, the use of bio-inspired leaf shape on the antenna array permits an increase in both bandwidth and gain. In comparison with wearable bio-inspired antenna with single leaf shape, wearable antenna arrays bio-inspired in Inga maritimus plant shape with four leaves presented gain 2.25 dBi greater than antenna array with two leaves, and 3.96 dBi greater than antenna with single leaf shape. From the radiation patterns of the bio-inspired antenna array with four elements, a lower HPBW (77) can be observed, which indicates a higher concentration of radiated energy, added to the highest gain (9.76 dBi), and a higher front-to-back ratio (23 dB), this indicates that the arrange-

ment can be used for communication of greater distances or with less signal intensity.

Wearable wireless systems impose new challenges to antenna design since the utilization in clothes, the proximity of the human body, and the possibility of format variations as bending implies in parameters like good esthetical appearance, low cost, integration to the clothes and accessories used next to the body, among others related to the wear like use of the antenna. In this chapter, we presented some trends for design innovative wearable bio-inspired antennas using plant leaves as inspiration parameterized by the Gielis formula to design antennas, and also we characterize different wearable flexible and low-cost dielectric materials (denim and

(RL), can be observed of each structure presented.

4. Conclusion

234 Wearable Technologies


[7] Silva Junior PF, Freire RCS, Serres AJR, Silva PHF, Silva JC. Wearable textile bioinsipired antenna for 2G, 3G and 4G systems. Microwave and Optical Technology Letters. 2016;58: 2818-2823. DOI: 10.1002/mop.30150

[21] Lee H, Tak J, Choi J. Wearable antenna integrated into military berets for indoor/outdoor positioning system. IEEE Antennas and Wireless Propagation Letters. 2017;16:1919-1922.

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[22] Kassem H, Vigneras FLG. Characterization techniques for materials properties measurement. In: Minin I, editor. Microwave Wave Technologies from Photonic Bandgap Devices to Atenna and Applications. Rijeka, Crotia: InTech; 2010. pp. 289-314. DOI: 10.5772/9055

[23] Bai Q, Langley R. Crumpled textile antennas. Electronics Letters. 2009;45:436-438. DOI:

[24] Rano D, Hashmi M. Design and analysis of wearable patch antenna array for MBAN applications. In: Twenty Second National Conference on Communication (NCC),

[25] Jasmine tattoo meaning [Internet]. 2015. Available from: http://vse-o-tattoo.ru/wp-content/ uploads/2015/06/chinese-tea-jasmine-flower-jpg.jpg [Accessed: 30 November 2017]

[26] Gonçalves FF, Macedo CC, Pasin LAAP. Caracterização Morfológica da Bidens Pilosa (In

[27] Serres AJR, Serres GKF, Silva Júnior PF, Freire RCS, Cruz JN, Albuquerque TC, Oliveria MA, Silva PHF. Bio-inspired micristrip antenna. In: Trends in Research on Microstrip

[28] Garcia FCP, Fernandes JM. Inga. In: Listas de Espécies da Flora do Brasil (In Portuguese), Rio de Janeiro [Internet]. 2012. Avalilable from: http://floradobrasil.jbrj.gov.br/ [Accessed:

Antennas. Rijeka, Crotia: Intech; 2017. pp. 87-109. DOI: 10.5772/intechopen.69766

Guwahati; 4–6 March 2016. pp. 1-6. DOI: 10.1109/NCC.2016.7561201

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[21] Lee H, Tak J, Choi J. Wearable antenna integrated into military berets for indoor/outdoor positioning system. IEEE Antennas and Wireless Propagation Letters. 2017;16:1919-1922. DOI: 10.1109/LAWP.2017.2688400

[7] Silva Junior PF, Freire RCS, Serres AJR, Silva PHF, Silva JC. Wearable textile bioinsipired antenna for 2G, 3G and 4G systems. Microwave and Optical Technology Letters. 2016;58:

[8] Gielis J. A generic geometric transformation that unifies a wide range of natural and abstract shapes. American Journal of Botany. 2003;90:333-338. DOI: 10.3732/ajb.90.3.333

[9] Pakrasi H. Natural Antennas: Structure & Efficiency [Internet]. 2012. Available from:

[10] Falconer K. Fractal Geometry: Mathematical Foundations and Applications. 2nd ed. Lon-

[11] Zarghooni B, Dadgarpour A, Pourahmadazar J, Denidni TA. Supershaped metamaterial unit-cells using the Gielis formula. In: IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, Vancouver. 19–24 July 2015;

[12] Serres AJR, Serres GKF, Silva Júnior PF, Freire RCS, Cruz JN, Albuquerque TC, Oliveira MA, Silva PHF. Bio-inspired microstrip antenna. In: Chattopladhyay B, editor. Trends in Research on Microstrip Antennas. Rijeka, Crotia: InTech; 2017. p. 88, 109. DOI: 10.5772/

[13] Silva Junior PF, Freire RC S, Serres AJR, Silva PHF, Silva JC. Bio-inspired antenna for UWB systems. In: 2016 1st International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT), Belo Horizonte; 29 Aug–3 Sept 2016. pp. 153-157. DOI: 10.1109/

[14] Silva Júnior PF, Freire RCS, Serres AJR, Catunda SY, Silva PHF. Bio-inspired transparent antenna for WLAN application in 5 GHz. Microwave and Optical Technology Letters.

[15] Khaleel H. Innovation in Wearable and Flexible Antennas. Boston: WIT Press; 2015. p. 215 [16] Balanis CA. Antenna Theory. Analysis and Design. 3nd ed. New York: Wiley; 2005. p. 941

[17] Stutzman WL, Thiele GA. Antenna Theory and Design. New York: Danvers; 2013. p. 820 [18] Mendes C, Peixeiro C. A dual-mode single-band wearable Microstrip antenna for body area networks. IEEE Antennas and Wireless Propagation Letters. 2017;16:3055-3058. DOI:

[19] Ashyap AYI, Abidin ZZ, Darlan SH, Majid HA, Shah SM, Kamarudin MR, Alomainy A. Compact and low-profile textile EBG-based antenna for wearable medical applications. IEEE Antennas and Wireless Propagation Letters. 2017;16:2550-2553. DOI: 10.1109/

[20] Saeed SM, Balanis CA, Birtcher CR, Durgun AC, Shaman HN. Wearable flexible reconfigurable antenna integrated with artificial magnetic conductor. IEEE Antennas and Wireless

Propagation Letters. 2017;16:2396-2399. DOI: 10.1109/LAWP.2017.2720558

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LAWP.2017.27323


**Chapter 12**

**Provisional chapter**

**Middleware-Driven Intelligent Glove for Industrial**

**Middleware-Driven Intelligent Glove for Industrial** 

It is estimated that by the year 2020, 700 million wearable technology devices will be sold worldwide. One of the reasons is the industries' need to increase their productivity. Some of the tools welcomed by industries are handheld devices such as tablets, PDAs and mobile phones. However, handheld devices are not ideal for industrial applications because they often subject users to fatigue during their long working hours. A viable solution to this problem is wearable devices. The advantage of wearable devices is that they become part of the user. Hence, they subject the user to less fatigue, thereby increasing their productivity. This chapter presents the development of an intelligent glove, which is designed to control actuators in an industrial environment. This system utilizes RTI connext data distributed service middleware to facilitate communication over WiFi. Our experiments show very promising results with maximum power consumption of 310 mW and latency as low as 23 ms. These results make the proposed system a perfect

**Keywords:** RTI, DDS, RTI connext DDS, ubiquitous computing, Internet of Things,

In manufacturing industries, automated industrial systems that are intelligent and cheap are necessary in order to increase efficiency and productivity [1, 2]. Traditionally, such intelligent systems are wired. However, they are now wireless, thanks to the increase in reliability and flexibility of wireless communication systems [3]. Most wireless control systems are controlled through one type of handheld device or another. This is due to their computational

DOI: 10.5772/intechopen.76382

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use,

distribution, and reproduction in any medium, provided the original work is properly cited.

Farouq Muhammad Aliyu and Basem Almadani

Farouq Muhammad Aliyu and Basem Almadani

Additional information is available at the end of the chapter

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76382

fit for most industrial applications.

embedded systems

**1. Introduction**

**Applications**

**Abstract**

**Applications**

#### **Middleware-Driven Intelligent Glove for Industrial Applications Middleware-Driven Intelligent Glove for Industrial Applications**

DOI: 10.5772/intechopen.76382

Farouq Muhammad Aliyu and Basem Almadani Farouq Muhammad Aliyu and Basem Almadani

Additional information is available at the end of the chapter Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.76382

#### **Abstract**

It is estimated that by the year 2020, 700 million wearable technology devices will be sold worldwide. One of the reasons is the industries' need to increase their productivity. Some of the tools welcomed by industries are handheld devices such as tablets, PDAs and mobile phones. However, handheld devices are not ideal for industrial applications because they often subject users to fatigue during their long working hours. A viable solution to this problem is wearable devices. The advantage of wearable devices is that they become part of the user. Hence, they subject the user to less fatigue, thereby increasing their productivity. This chapter presents the development of an intelligent glove, which is designed to control actuators in an industrial environment. This system utilizes RTI connext data distributed service middleware to facilitate communication over WiFi. Our experiments show very promising results with maximum power consumption of 310 mW and latency as low as 23 ms. These results make the proposed system a perfect fit for most industrial applications.

**Keywords:** RTI, DDS, RTI connext DDS, ubiquitous computing, Internet of Things, embedded systems

### **1. Introduction**

In manufacturing industries, automated industrial systems that are intelligent and cheap are necessary in order to increase efficiency and productivity [1, 2]. Traditionally, such intelligent systems are wired. However, they are now wireless, thanks to the increase in reliability and flexibility of wireless communication systems [3]. Most wireless control systems are controlled through one type of handheld device or another. This is due to their computational

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

capabilities and energy efficiency. But recent developments in embedded systems have given rise to smaller yet more powerful embedded processors. As such, researchers are now turning their attention toward wearable devices.

obtain high bandwidth. The tablet PC communicates with programmable logic controllers (PLCs) via the PC station. This approach has some problems: first, the workstation between the tablet PC and the PLCs exerts delay overhead even though WLAN is used to speed up communication between the tablet PC and the PLCs and second, albeit tablet PCs are handheld PCs, their size may discomfort and/or distract the user in some industrial applications. Nowadays, the developments in embedded systems allow researchers to replace tablets with smaller footprint but equally powerful processing devices. Yang et al. [16] developed a device that traces the wearer's body position and his movements using PIC microcontroller, a triaxial accelerometer and an RF transmitter. This device is intended for medical applications. It comes in handy for people with the tendency to syncope while they are alone. However, the system lacks enough computation power. Hence it cannot cope with the rigorous data processing of industrial applications. Single board computers (SBCs) like Beagle Bone, Intel Galileo and Raspberry Pi have small footprint yet they have large processing power [17, 18, 19]. This enabled the researchers to replace phones, tablets and computers with SBC in control systems and WeSN [20]. Wang et al. [21] developed a wearable sensor network using Raspberry Pi. The system is used for crowd-sensing. It uses transcoding algorithm to reduce resolution of video files. Khelil et al. [22] developed a body sensor network (BSN) using Raspberry Pi. The system uses cooking hacks e-health shield, which contains an airflow sensor for measuring wearer's respiratory rate, a pulse oximeter for measuring oxygen saturation of hemoglobin and position sensor for motion tracking. Jutila et al. [23] used Intel Galileo as a sink node for

Middleware-Driven Intelligent Glove for Industrial Applications

http://dx.doi.org/10.5772/intechopen.76382

241

The aforementioned SBC systems revealed promising results. However, there exists incompatibility between the different types of SBCs. Therefore, a WeSN system can only contain one type of SBC. This problem is a serious setback in industrial applications of WSN and/ or WeSN. This incompatibility forces engineers to stick to one type of device, which exposes them to the tendency of discontinued support by the producing company. In order to tackle this problem, [24, 25] proposed the use of middleware. A middleware is a software capable of hiding the complexity and heterogeneity between system components. It increases the ease of

Fok et al. [27] developed a fire tracking system which uses mobile agents based on Agilla middleware. This system allows a fire tuple to be injected into the network, where they clone themselves and move from one node to another until they form a perimeter bounding the fire. The system recorded huge success and also proves that a multipurpose and multitask WSN can be developed. Zhai et al. [28] developed a publish/subscribe middleware called wireless messageoriented system (WMOS) on top of TinyOS. The authors were able to reduce overall energy consumption of the network through the use of self-adaptive quality of service (QoS) services and content/topic model. Zug et al. [29] successfully applied a publish/subscribe middleware Family of Adaptive Middleware for autonomOUs Sentient Objects (FAMOUSO) to an industrial automation system using Katana robot. The robot publishes its coordinates and angles and it subscribes to movement, speed and emergency stop commands. This middleware can only work optimally in certain fixed conditions as it does not have quality of service (QoS) parameters. These parameters can be set to fine tune the performance of the middleware thereby improving the performance of the system at large. Furthermore, the aforementioned middlewares are

managing systems' resources and improves the predictability of the system [26].

a wearable system that helps track children at school.

In wearable sensor network (WeSN), sensor nodes are designed to gather physiological and kinetic data from the wearers' bodies [4]. These devices extend the users' intelligence and their ability to interact with the environment. They also take advantage of the intimacy between the user, the computer and the environment [5]. Wearable sensors can be helpful in industrial applications that require mobile users [6]. They provide more natural avenues of interacting with the system [7, 8]. In some scenarios handheld devices are inapplicable or too expensive [9, 10]. Furthermore, embedded devices are design specific. Therefore, they are optimized for a given function, unlike their handheld counterparts. This gives them upper hand when it comes to accuracy and reliability [11].

Anliker et al. [12] discussed the properties of a good WeSN. The authors stated that a good WeSN should have: (1)The ability to act in a proactive manner rather than depend on user's commands; (2) the ability to gather complex information regarding the user's interaction with the world; (3) high connectivity and mobility; (4) the ability to process wide variety of data at high speeds with low power consumption; (5) the ability to combine I/O devices and sensors from different parts of the body into one heterogeneous system; and (6) inconspicuous appearance such that it does not change the users' look in an unacceptable way or hinder the user from carrying out his/her normal day-to-day activities.

Sadly, there has been little research in WeSN with focus on industrial applications. This is due to the fact that distributed embedded systems at an industrial scale are not easy to maintain and control. In this chapter, we present the development of an intelligent hand glove for an industrial-based networked control system (NCS). NCS is a distributed control system (DCS) where sensors, actuators and controllers communicate over a network [13]. In order to ensure real-time performance, real time innovations (RTI) connext middleware is used. The middleware is used to manage the heterogeneous distributed system at real time. Also, the project is designed to investigate whether intelligent wearable sensors can replace the present handheld devices used in industrial NCS applications. We do believe that many users are in support and keen to use wearable devices than handheld devices. This is because they are lighter, cheaper, consume less energy and are more convenient to carry around.

### **2. Industrial application of embedded devices**

Researchers were able to apply handheld devices such as smart phones and personal digital assistants to networked control system (NCS) [14]. Görlich et al. [15] developed an NCS where a Profibus-to-Bluetooth connection is used to control and parameterize a flow unit via Nokia 6280 mobile phone. Nonetheless, this system suffers from incompatibility, limited communication range and low bandwidth. Huang et al. [6] developed an oil and gas storage and transportation simulation system (OGSTSS). The proposed OGSTSS system uses wireless local area network (WLAN) and an android tablet PC in order to cover longer range and obtain high bandwidth. The tablet PC communicates with programmable logic controllers (PLCs) via the PC station. This approach has some problems: first, the workstation between the tablet PC and the PLCs exerts delay overhead even though WLAN is used to speed up communication between the tablet PC and the PLCs and second, albeit tablet PCs are handheld PCs, their size may discomfort and/or distract the user in some industrial applications.

capabilities and energy efficiency. But recent developments in embedded systems have given rise to smaller yet more powerful embedded processors. As such, researchers are now turning

In wearable sensor network (WeSN), sensor nodes are designed to gather physiological and kinetic data from the wearers' bodies [4]. These devices extend the users' intelligence and their ability to interact with the environment. They also take advantage of the intimacy between the user, the computer and the environment [5]. Wearable sensors can be helpful in industrial applications that require mobile users [6]. They provide more natural avenues of interacting with the system [7, 8]. In some scenarios handheld devices are inapplicable or too expensive [9, 10]. Furthermore, embedded devices are design specific. Therefore, they are optimized for a given function, unlike their handheld counterparts. This gives them upper hand when it

Anliker et al. [12] discussed the properties of a good WeSN. The authors stated that a good WeSN should have: (1)The ability to act in a proactive manner rather than depend on user's commands; (2) the ability to gather complex information regarding the user's interaction with the world; (3) high connectivity and mobility; (4) the ability to process wide variety of data at high speeds with low power consumption; (5) the ability to combine I/O devices and sensors from different parts of the body into one heterogeneous system; and (6) inconspicuous appearance such that it does not change the users' look in an unacceptable way or hinder the

Sadly, there has been little research in WeSN with focus on industrial applications. This is due to the fact that distributed embedded systems at an industrial scale are not easy to maintain and control. In this chapter, we present the development of an intelligent hand glove for an industrial-based networked control system (NCS). NCS is a distributed control system (DCS) where sensors, actuators and controllers communicate over a network [13]. In order to ensure real-time performance, real time innovations (RTI) connext middleware is used. The middleware is used to manage the heterogeneous distributed system at real time. Also, the project is designed to investigate whether intelligent wearable sensors can replace the present handheld devices used in industrial NCS applications. We do believe that many users are in support and keen to use wearable devices than handheld devices. This is because they are

Researchers were able to apply handheld devices such as smart phones and personal digital assistants to networked control system (NCS) [14]. Görlich et al. [15] developed an NCS where a Profibus-to-Bluetooth connection is used to control and parameterize a flow unit via Nokia 6280 mobile phone. Nonetheless, this system suffers from incompatibility, limited communication range and low bandwidth. Huang et al. [6] developed an oil and gas storage and transportation simulation system (OGSTSS). The proposed OGSTSS system uses wireless local area network (WLAN) and an android tablet PC in order to cover longer range and

lighter, cheaper, consume less energy and are more convenient to carry around.

their attention toward wearable devices.

240 Wearable Technologies

comes to accuracy and reliability [11].

user from carrying out his/her normal day-to-day activities.

**2. Industrial application of embedded devices**

Nowadays, the developments in embedded systems allow researchers to replace tablets with smaller footprint but equally powerful processing devices. Yang et al. [16] developed a device that traces the wearer's body position and his movements using PIC microcontroller, a triaxial accelerometer and an RF transmitter. This device is intended for medical applications. It comes in handy for people with the tendency to syncope while they are alone. However, the system lacks enough computation power. Hence it cannot cope with the rigorous data processing of industrial applications. Single board computers (SBCs) like Beagle Bone, Intel Galileo and Raspberry Pi have small footprint yet they have large processing power [17, 18, 19]. This enabled the researchers to replace phones, tablets and computers with SBC in control systems and WeSN [20]. Wang et al. [21] developed a wearable sensor network using Raspberry Pi. The system is used for crowd-sensing. It uses transcoding algorithm to reduce resolution of video files. Khelil et al. [22] developed a body sensor network (BSN) using Raspberry Pi. The system uses cooking hacks e-health shield, which contains an airflow sensor for measuring wearer's respiratory rate, a pulse oximeter for measuring oxygen saturation of hemoglobin and position sensor for motion tracking. Jutila et al. [23] used Intel Galileo as a sink node for a wearable system that helps track children at school.

The aforementioned SBC systems revealed promising results. However, there exists incompatibility between the different types of SBCs. Therefore, a WeSN system can only contain one type of SBC. This problem is a serious setback in industrial applications of WSN and/ or WeSN. This incompatibility forces engineers to stick to one type of device, which exposes them to the tendency of discontinued support by the producing company. In order to tackle this problem, [24, 25] proposed the use of middleware. A middleware is a software capable of hiding the complexity and heterogeneity between system components. It increases the ease of managing systems' resources and improves the predictability of the system [26].

Fok et al. [27] developed a fire tracking system which uses mobile agents based on Agilla middleware. This system allows a fire tuple to be injected into the network, where they clone themselves and move from one node to another until they form a perimeter bounding the fire. The system recorded huge success and also proves that a multipurpose and multitask WSN can be developed. Zhai et al. [28] developed a publish/subscribe middleware called wireless messageoriented system (WMOS) on top of TinyOS. The authors were able to reduce overall energy consumption of the network through the use of self-adaptive quality of service (QoS) services and content/topic model. Zug et al. [29] successfully applied a publish/subscribe middleware Family of Adaptive Middleware for autonomOUs Sentient Objects (FAMOUSO) to an industrial automation system using Katana robot. The robot publishes its coordinates and angles and it subscribes to movement, speed and emergency stop commands. This middleware can only work optimally in certain fixed conditions as it does not have quality of service (QoS) parameters. These parameters can be set to fine tune the performance of the middleware thereby improving the performance of the system at large. Furthermore, the aforementioned middlewares are WSN middlewares. Hence, they cannot be used in industrial environment, where a heterogeneous system consisting of embedded devices and computers is readily found.

connext professional (e.g., PC, Beagle Bone, Intel Galileo or Raspberry Pi); and (4) an actuator

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243

Al-Yad is a smart hand glove made up of a combination of light sources (light emitting diodes (LEDs)) and light sinks (light dependent resistors (LDRs)). The 5 mm round red LED is chosen because the LDR is very sensitive to it and it consumes a maximum of 78 mw. A 50 mW, N5 AC-501085-type LDR is chosen for the proposed system because it has small-form factor

The LDRs and the LEDs are in line of sight when fingers of the wearer are stretched straight. This gives a high signal (see **Figure 2**). As the user bends his fingers the light stops reaching the LDRs. This raises the resistance of the LDRs, thus, giving low output signal. In order to ensure no ambient light contaminates the system, the LDR is placed in a hollow cylinder of 1.45 cm in depth. Furthermore, the light source is pulsed at a frequency of 5 kHz, which is the highest frequency of PWM based on "wiringpi.h" implementation [30]. The highest frequency available is chosen because the higher the frequency, the smaller the capacitor required, therefore, the lighter the hand glove. Lemma 3.2 shows how the size of the capacitor C2 is derived. The pulsing light and the ambient light add up to form the simulated waveform, as shown in **Figure 3**. The direct current (DC) component of the wave

represents any industrial machinery and that is required to be controlled remotely.

**3.1. Al-yad**

and consumes small amount of energy.

**Figure 2.** Proposed systems complete circuit diagram.

The proposed system presented in this chapter is a smart hand glove that accepts hand gesture as input, processes it using an ARM microprocessor (Raspberry Pi) and then publishes it using the RTI connext professional (publish/subscribe middleware) via WiFi. With the proposed architecture, we were able to resolve the data processing constraints, the large hardware footprint problem and the communication delays encountered by the industrial-based wearable systems.

### **3. System architecture**

**Figure 1** shows the proposed system architecture. The system architecture consists of the following four main components: (1) a wearable sensor named Al-yad. The main function of this component is to convert the physical movements into electric signals. The electric signal is then conditioned so that it can be processed by the 3.3 v ARM-6 microprocessor, Raspberry Pi in the case of this research; (2) a real-time innovations connext professional is selected as a middleware to mediate between the wearable sensor and other computing devices of the system. This middleware is selected because of its ability to work on both embedded devices and workstations. It also has a wealth of QoS that can be used to optimize communication as well as energy consumption; (3) a computing device can be any device capable of running

**Figure 1.** System structure.

connext professional (e.g., PC, Beagle Bone, Intel Galileo or Raspberry Pi); and (4) an actuator represents any industrial machinery and that is required to be controlled remotely.

#### **3.1. Al-yad**

WSN middlewares. Hence, they cannot be used in industrial environment, where a heteroge-

The proposed system presented in this chapter is a smart hand glove that accepts hand gesture as input, processes it using an ARM microprocessor (Raspberry Pi) and then publishes it using the RTI connext professional (publish/subscribe middleware) via WiFi. With the proposed architecture, we were able to resolve the data processing constraints, the large hardware footprint problem and the communication delays encountered by the industrial-based

**Figure 1** shows the proposed system architecture. The system architecture consists of the following four main components: (1) a wearable sensor named Al-yad. The main function of this component is to convert the physical movements into electric signals. The electric signal is then conditioned so that it can be processed by the 3.3 v ARM-6 microprocessor, Raspberry Pi in the case of this research; (2) a real-time innovations connext professional is selected as a middleware to mediate between the wearable sensor and other computing devices of the system. This middleware is selected because of its ability to work on both embedded devices and workstations. It also has a wealth of QoS that can be used to optimize communication as well as energy consumption; (3) a computing device can be any device capable of running

neous system consisting of embedded devices and computers is readily found.

wearable systems.

242 Wearable Technologies

**Figure 1.** System structure.

**3. System architecture**

Al-Yad is a smart hand glove made up of a combination of light sources (light emitting diodes (LEDs)) and light sinks (light dependent resistors (LDRs)). The 5 mm round red LED is chosen because the LDR is very sensitive to it and it consumes a maximum of 78 mw. A 50 mW, N5 AC-501085-type LDR is chosen for the proposed system because it has small-form factor and consumes small amount of energy.

The LDRs and the LEDs are in line of sight when fingers of the wearer are stretched straight. This gives a high signal (see **Figure 2**). As the user bends his fingers the light stops reaching the LDRs. This raises the resistance of the LDRs, thus, giving low output signal. In order to ensure no ambient light contaminates the system, the LDR is placed in a hollow cylinder of 1.45 cm in depth. Furthermore, the light source is pulsed at a frequency of 5 kHz, which is the highest frequency of PWM based on "wiringpi.h" implementation [30]. The highest frequency available is chosen because the higher the frequency, the smaller the capacitor required, therefore, the lighter the hand glove. Lemma 3.2 shows how the size of the capacitor C2 is derived. The pulsing light and the ambient light add up to form the simulated waveform, as shown in **Figure 3**. The direct current (DC) component of the wave

**Figure 2.** Proposed systems complete circuit diagram.

*XC*<sup>1</sup> <sup>=</sup> \_\_\_\_\_\_\_\_\_\_\_\_ 1 2*<sup>π</sup>* <sup>×</sup> *<sup>f</sup>* <sup>×</sup> *<sup>C</sup>*<sup>1</sup>

2*π* × 5000 × 1

<sup>1</sup> <sup>=</sup> \_\_\_\_\_\_\_\_\_\_\_ 1 2*<sup>π</sup>* <sup>×</sup> <sup>5000</sup> <sup>×</sup> *<sup>C</sup>*<sup>1</sup> *<sup>C</sup>*<sup>1</sup> <sup>=</sup> \_\_\_\_\_\_\_\_\_\_ <sup>1</sup>

*C*1 = 3.1831 × 10<sup>−</sup><sup>6</sup>

*C*1 ≈ 3.3*μf*

Algorithm 1 illustrates the behavior of the SBC in the system.

then published as a command.

**Quality of service Value**

Durability kind = VOLATILE Reliability kind = RELIABLE

Liveliness kind = AUTOMATIC

History kind = KEEP LAST

Presentation Access\_scope = TOPIC

Owner kind = EXCLUSIVE

**Table 1.** QoS used in the proposed systems' middleware.

Time\_Based\_Filter Minimum separation = 0:2 s

Owner\_Strength 5

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In addition, a rectifying diode (1 N4001) is added to the system in order to prevent negative voltage from reaching the Schmitt trigger (74LS14). 1 N4001 is used because it is the smallest diode that can be used without compromising the reliability of the system. A C2 capacitor is added to the system in order to reduce the ripples down to 0.1% so that the Schmitt trigger receives an almost constant direct current (DC) voltage. Finally, the Schmitt trigger (LM7414) smoothens the signal, making it a perfect DC, which is then passed to the microprocessor without any debouncing effect [31]. In order to ensure accurate data acquisition, the sampling frequency for the hand movement is chosen to be 5 Hz which is a little more than what is recommended by Yuan et al. [32]. Six sensors are placed in three fingers, thereby producing six bits. Two zeros are padded to the upper two bits, as shown in line 3–10 of Algorithm 1. The resulting 8-bit signal is then converted into an integer, which is

The processing unit is made up of a single board computer (SBC) [33]. Raspberry Pi is chosen because it has abundant libraries in Python, C, C++ and Java. The SBC is programmed to scan the glove and convert the gloves input to an integer and publish it through the middleware.

max blocking time = 100 ms

lease duration = 1 s

Ordered\_access = True Coherent\_access = False

depth = 5

(2)

245

**Figure 3.** Transducer circuit design.

is formed as a result of the ambient light. A coupling capacitor (C1) is added to the circuit in order to remove the DC component. Lemma 3.2 shows how the value of the capacitor is derived.

**Lemma 3.1:** Let γ = 0.1% be the ripple factor of the half wave DC and f = 5 kHz be the frequency of the pulsing light. Since the input impedance (RL) of a 7414 Schmitt trigger is very high, let RL = 1 MΩ. Hence, the capacitance of C2 capacitor can be calculated as:

$$\begin{aligned} \mathcal{V} &= \frac{1}{2\pi \times f \times \mathcal{C} \times \mathcal{R}\_{\mathbb{L}}} \\\\ 0.1\% &= \frac{1}{2\pi \times 5000 \times \mathcal{C} 2 \times 1 \times 10^{6}} \\\\ \mathcal{C}2 &= 31.8310 \times 10^{-9} \\\\ \mathcal{C}2 &\approx 33nf \end{aligned} \tag{1}$$

**Lemma 3.2:** Let XC1 be the capacitive reactance of the capacitor C1 and the pulsing light frequency (f) is 40 kHz. Since the input impedance of a 7414 Schmitt trigger is very high, then any value can be chosen for XC1. For simplicity, we choose XC1 = 1. Hence, capacitance of C1 capacitor can be calculated as follows:

$$\begin{aligned} X\_{\text{Cl}} &= \frac{1}{2\pi \times f \times \text{Cl}} \\ 1 &= \frac{1}{2\pi \times 5000 \times \text{Cl}} \\ \text{Cl} &= \frac{1}{2\pi \times 5000 \times 1} \\ \text{Cl} &= 3.1831 \times 10^{-6} \\ \text{Cl} &\approx 3.3 \mu f \end{aligned} \tag{2}$$

In addition, a rectifying diode (1 N4001) is added to the system in order to prevent negative voltage from reaching the Schmitt trigger (74LS14). 1 N4001 is used because it is the smallest diode that can be used without compromising the reliability of the system. A C2 capacitor is added to the system in order to reduce the ripples down to 0.1% so that the Schmitt trigger receives an almost constant direct current (DC) voltage. Finally, the Schmitt trigger (LM7414) smoothens the signal, making it a perfect DC, which is then passed to the microprocessor without any debouncing effect [31]. In order to ensure accurate data acquisition, the sampling frequency for the hand movement is chosen to be 5 Hz which is a little more than what is recommended by Yuan et al. [32]. Six sensors are placed in three fingers, thereby producing six bits. Two zeros are padded to the upper two bits, as shown in line 3–10 of Algorithm 1. The resulting 8-bit signal is then converted into an integer, which is then published as a command.

The processing unit is made up of a single board computer (SBC) [33]. Raspberry Pi is chosen because it has abundant libraries in Python, C, C++ and Java. The SBC is programmed to scan the glove and convert the gloves input to an integer and publish it through the middleware. Algorithm 1 illustrates the behavior of the SBC in the system.


**Table 1.** QoS used in the proposed systems' middleware.

is formed as a result of the ambient light. A coupling capacitor (C1) is added to the circuit in order to remove the DC component. Lemma 3.2 shows how the value of the capacitor

**Lemma 3.1:** Let γ = 0.1% be the ripple factor of the half wave DC and f = 5 kHz be the frequency of the pulsing light. Since the input impedance (RL) of a 7414 Schmitt trigger is very

**Lemma 3.2:** Let XC1 be the capacitive reactance of the capacitor C1 and the pulsing light frequency (f) is 40 kHz. Since the input impedance of a 7414 Schmitt trigger is very high, then any value can be chosen for XC1. For simplicity, we choose XC1 = 1. Hence, capacitance of C1

(1)

high, let RL = 1 MΩ. Hence, the capacitance of C2 capacitor can be calculated as:

0.1% <sup>=</sup> \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 1 2*<sup>π</sup>* <sup>×</sup> <sup>5000</sup> <sup>×</sup> *<sup>C</sup>*<sup>2</sup> <sup>×</sup> <sup>1</sup> <sup>×</sup> <sup>106</sup>

*<sup>γ</sup>* <sup>=</sup> \_\_\_\_\_\_\_\_\_\_\_\_ 1 2*<sup>π</sup>* <sup>×</sup> *<sup>f</sup>* <sup>×</sup> *<sup>C</sup>*<sup>2</sup> <sup>×</sup> *RL*

*C*2 = 31.8310 × 10<sup>−</sup><sup>9</sup>

*C*2 ≈ 33*nf*

capacitor can be calculated as follows:

is derived.

244 Wearable Technologies

**Figure 3.** Transducer circuit design.

#### **3.2. Middleware**

Research has shown that DDS middleware can achieve up to 75% success rate in mobile node applications [34]. This and the reason that it hides heterogeneity of a system encourages the use of middleware in our proposed solution. The middleware chosen for this task is RTI connext middleware. This middleware is chosen due to its strict compliance with the object management group (OMG) specification for data distribution service middleware [35]. The middleware is implemented according to Algorithm 1 using C++ programming language.

**4.** *History* QoS allows the datawriter to cache some samples. Here, the datawriter is allowed

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**5.** *Presentation* is set such that the middleware will ensure that the samples are accessed in the

**6.** *Owner* is set to *EXCLUSIVE* so that only the hand glove with the highest owner strength

**7.** *Owner\_Strength* is set to five. This is the maximum number of gloves that can be used in the system. Therefore, only when a glove with the strength of five is down the glove with

**8.** *Time\_Based\_Filter's* minimum separation is the minimum time period before a new command is sent to the datareader. Since the sampling rate is 5 Hz, then the minimum separa-

When a user wants to control a machine, he/she makes a gesture equivalent to the required command. The gesture is converted into a byte of command and is transmitted to a processing device. The processing device is connected to the machine to be controlled. It is responsible for subscribing and converting the sent signal into commands usable by the target machine. Any device capable of using RTI middleware can be used as the processing device. In the case of our experiment a PC workstation with Intel Core i5 microprocessor and Atheros AR8161/8165

The sensor casings are designed using Blender 2.6 3D modeling software and they are printed with Replicator2 3D printer. LEDs and LDRs are placed in the 3D printed casings. They are connected in a manner, as shown in **Figure 4**. The conditioning circuit is then connected to the SBC/Raspberry Pi, where the data is processed and transmitted to the actuator. In our experiments, a PC is used as the actuator. A RTI subscriber is installed on a PC and publisher on the Raspberry Pi. The gesture commands sent by the Raspberry Pi are received by the PC and

In this research throughput, latency, power consumption and comfort of the system are evaluated. The setup in **Figure 5** is used to measure both latency and throughput. RTI's performance toolkit, "Perftest," is used [37]. To test latency of the system, packets are sequenced and time stamped before they are transmitted to the datareader (receiver). The packets are immediately re-routed (i.e., bounced) back to the transmitter where the round trip time (RTT) is calculated. Similarly, the receiver counts the number of packets received per second in order to calculate the throughput. Finally, the transmitter reports the latency of the system while the receiver reports its throughput. As illustrated in the setup in **Figure 5**, Perftest was executed as a publisher on the Raspberry Pi and as a subscriber on the PC. The latency and

displayed on the monitor. It is with this setup that all experiments are carried out.

to queue only five samples.

order they were sent by the operator.

can control the target machine.

strength four takes over and so on.

tion = 1/(5 Hz) = 0.2 s.

Gigabit Ethernet Controller is used.

**3.3. Processing device**

**4. Experiments**


The QoS is configured in both the hand glove and the actuator in order to ensure compatibility and efficiency. **Table 1** shows the quality of services used in the proposed system. The first four QoSs in **Table 1** are the recommended QoSs for alarm/event systems by [36]. The remaining QoSs are selected by the authors in order to ensure that the system behaves in a controller-actuator manner. The following is an explanation for the used QoSs:


#### **3.3. Processing device**

**3.2. Middleware**

246 Wearable Technologies

Research has shown that DDS middleware can achieve up to 75% success rate in mobile node applications [34]. This and the reason that it hides heterogeneity of a system encourages the use of middleware in our proposed solution. The middleware chosen for this task is RTI connext middleware. This middleware is chosen due to its strict compliance with the object management group (OMG) specification for data distribution service middleware [35]. The middleware is implemented according to Algorithm 1 using C++ programming language.

The QoS is configured in both the hand glove and the actuator in order to ensure compatibility and efficiency. **Table 1** shows the quality of services used in the proposed system. The first four QoSs in **Table 1** are the recommended QoSs for alarm/event systems by [36]. The remaining QoSs are selected by the authors in order to ensure that the system behaves in a

**1.** *Durability* is set to "*VOLATILE*" so that data is not stored for future datareaders (i.e., targeted machine/actuator). This will prevent the targeted machine from executing any command that was issued before it was turned on, hence reducing the possibility of accidents.

**2.** *Reliability* of communication is set to "*RELIABLE*" and the maximum blocking time is left at the default value, which is 100 ms. The setting ensures that all commands published

**3.** *Liveliness* allows datareader to know when the datawriter (i.e., the wearable sensor) is dead or disconnected. It is set to *AUTOMATIC* and the lease time is set to 1 s so that the datar-

controller-actuator manner. The following is an explanation for the used QoSs:

eader automatically checks the presence of the datawriter every second.

reach the targeted subscriber.

When a user wants to control a machine, he/she makes a gesture equivalent to the required command. The gesture is converted into a byte of command and is transmitted to a processing device. The processing device is connected to the machine to be controlled. It is responsible for subscribing and converting the sent signal into commands usable by the target machine. Any device capable of using RTI middleware can be used as the processing device. In the case of our experiment a PC workstation with Intel Core i5 microprocessor and Atheros AR8161/8165 Gigabit Ethernet Controller is used.

### **4. Experiments**

The sensor casings are designed using Blender 2.6 3D modeling software and they are printed with Replicator2 3D printer. LEDs and LDRs are placed in the 3D printed casings. They are connected in a manner, as shown in **Figure 4**. The conditioning circuit is then connected to the SBC/Raspberry Pi, where the data is processed and transmitted to the actuator. In our experiments, a PC is used as the actuator. A RTI subscriber is installed on a PC and publisher on the Raspberry Pi. The gesture commands sent by the Raspberry Pi are received by the PC and displayed on the monitor. It is with this setup that all experiments are carried out.

In this research throughput, latency, power consumption and comfort of the system are evaluated. The setup in **Figure 5** is used to measure both latency and throughput. RTI's performance toolkit, "Perftest," is used [37]. To test latency of the system, packets are sequenced and time stamped before they are transmitted to the datareader (receiver). The packets are immediately re-routed (i.e., bounced) back to the transmitter where the round trip time (RTT) is calculated. Similarly, the receiver counts the number of packets received per second in order to calculate the throughput. Finally, the transmitter reports the latency of the system while the receiver reports its throughput. As illustrated in the setup in **Figure 5**, Perftest was executed as a publisher on the Raspberry Pi and as a subscriber on the PC. The latency and

**Figure 4.** Proposed system.

**Figure 6.** Experiment setup for measuring energy consumed by the system.

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**Figure 7.** Latency of the proposed system.

**Figure 5.** Experiment setup for measuring latency and throughput.

throughput of the system is then measured. The payload size for the experiment is 28 bytes. This packet size is chosen because the proposed system only sends integer values between 0 and 63 and the minimum allowable payload size in RTI connext is 28 bytes. Furthermore, the experiment is carried out using QoS settings and without QoS, so as to investigate the cost of applying the quality of service. **Figures 6** and **7** show the results obtained for latency and throughput of the system, respectively.

We performed an experiment to ascertain the response time of the transducer. This is necessary because LDRs naturally have a very slow response. Therefore, it is important to know what quota of the total delay is contributed to it. In this experiment, the hand glove is connected to an oscilloscope and the output voltage (Vo) is fed to the Raspberry Pi and to the oscilloscope. The light is blocked and the response time is obtained through the oscilloscope, as shown in **Figure 8**.

The setup in **Figure 6** is used to measure the energy consumption of the whole system. A 1 resistor is connected in series with the proposed system so that the current passing through the system and the resistor is the same. As such, the voltage drop across the resistor follows

**Figure 6.** Experiment setup for measuring energy consumed by the system.

**Figure 7.** Latency of the proposed system.

throughput of the system is then measured. The payload size for the experiment is 28 bytes. This packet size is chosen because the proposed system only sends integer values between 0 and 63 and the minimum allowable payload size in RTI connext is 28 bytes. Furthermore, the experiment is carried out using QoS settings and without QoS, so as to investigate the cost of applying the quality of service. **Figures 6** and **7** show the results obtained for latency and

We performed an experiment to ascertain the response time of the transducer. This is necessary because LDRs naturally have a very slow response. Therefore, it is important to know what quota of the total delay is contributed to it. In this experiment, the hand glove is connected to an oscilloscope and the output voltage (Vo) is fed to the Raspberry Pi and to the oscilloscope. The light is blocked and the response time is obtained through the oscilloscope, as shown in **Figure 8**. The setup in **Figure 6** is used to measure the energy consumption of the whole system. A 1 resistor is connected in series with the proposed system so that the current passing through the system and the resistor is the same. As such, the voltage drop across the resistor follows

throughput of the system, respectively.

**Figure 4.** Proposed system.

248 Wearable Technologies

**Figure 5.** Experiment setup for measuring latency and throughput.

**Figure 8.** Throughput of the proposed system.

the same behavior as the current flowing through the circuit. To measure the actual current (I) flowing through the system, we used Eq. (3). The assumption in Eq. (3) is safe due to the fact that the Thevenin's resistance of the system is far greater than 1. An analogue to digital converter (ADC) is connected across the 1 resistor. It samples the voltage drop across the resistor every 200 ms. The acquired data is then transmitted to a computer via USB, where it is stored. The current flow through the system is recorded for two transmissions after which the WiFi dongle is immediately removed so as to record the overhead of the dongle itself.

$$I = \frac{V}{R}$$

$$I = \frac{V}{1} \text{ : } I = V$$

require them to score the attributes between 0 and 10. The score 0 represents the least while 10

The latency of the system with and without QoS also showed a minor difference of 1 ms. This can be seen from **Figure 7**. The performance test toolkit calculates an approximation of the latency by dividing round trip time (RTT) by 2. Since this is not a reliable answer, the software also reports the average and the standard deviation, as shown in **Table 2**. The transmission's throughput and latency results obtained show that QoS has little effect on the performance of

**Figure 8** shows that there is a little difference in the throughput of the system with or without using QoS. It is found that the average throughput of the system with QoS is 769 and 778 Mbps without QoS. In both cases no packets are lost during the 100,000 packet transmission. Given the fact that we are only sending commands in the form of integers over the network,

Moreover, the total latency of the system is the sum of the latency due to transmission and the inherent delay of the electric circuit that reads the hand gesture and places it on a bus for the SBC to read. **Figure 9** shows us that both the rising time of the signal and its falling time are approximately 20 ms. Therefore, the total delay of the system is 23 ms, as calculated using Eq. (4).

*delay* = 20 + 3.297 *t*

**Figure 10** shows the current (top) and the moving average of the current (bottom) flowing through the system during and after data transmission. Immediately after the last transmission, the WiFi dongle is removed, hence, the spike at 375th s. However, no change in the

*delay* = 23.3 ms (4)

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the proposed system. This is attributed to the small size of the packets transmitted.

represents most severe discomfort on the user.

**5. Discussion of results**

this result is highly acceptable.

*t*

**Table 2.** Latency results.

*delay* = *t*

*glove* + *t trans t*

**Parameter Value obtained** Ave latency 3.297 ms Std. deviation 0.6983 ms Min. latency 1.905 ms Max. latency 3.881 ms 50th percentile 3.707 ms 90th percentile 3.881 ms 99th percentile 3.881 ms 99.99th percentile 3.881 ms

Finally, a survey is contacted to investigate the ergonomics of the proposed system. Questionnaires are given to eight people. The questionnaire investigated the six attributes of comfort proposed by James and Chris [38]. Their comfort scale consists of the following attributes: emotion, attachment, harm, perceived change, movement and anxiety. The participants are asked to use the hand glove and then they are asked to answer 12 questions. The questions require them to score the attributes between 0 and 10. The score 0 represents the least while 10 represents most severe discomfort on the user.

### **5. Discussion of results**

The latency of the system with and without QoS also showed a minor difference of 1 ms. This can be seen from **Figure 7**. The performance test toolkit calculates an approximation of the latency by dividing round trip time (RTT) by 2. Since this is not a reliable answer, the software also reports the average and the standard deviation, as shown in **Table 2**. The transmission's throughput and latency results obtained show that QoS has little effect on the performance of the proposed system. This is attributed to the small size of the packets transmitted.

**Figure 8** shows that there is a little difference in the throughput of the system with or without using QoS. It is found that the average throughput of the system with QoS is 769 and 778 Mbps without QoS. In both cases no packets are lost during the 100,000 packet transmission. Given the fact that we are only sending commands in the form of integers over the network, this result is highly acceptable.

Moreover, the total latency of the system is the sum of the latency due to transmission and the inherent delay of the electric circuit that reads the hand gesture and places it on a bus for the SBC to read. **Figure 9** shows us that both the rising time of the signal and its falling time are approximately 20 ms. Therefore, the total delay of the system is 23 ms, as calculated using Eq. (4).

$$t\_{delay} = t\_{plane} + t\_{tus} \\ t\_{delay} = 20 + 3.297 \\ t\_{delay} = 23.3 \text{ ms} \tag{4}$$

**Figure 10** shows the current (top) and the moving average of the current (bottom) flowing through the system during and after data transmission. Immediately after the last transmission, the WiFi dongle is removed, hence, the spike at 375th s. However, no change in the


**Table 2.** Latency results.

the same behavior as the current flowing through the circuit. To measure the actual current (I) flowing through the system, we used Eq. (3). The assumption in Eq. (3) is safe due to the fact that the Thevenin's resistance of the system is far greater than 1. An analogue to digital converter (ADC) is connected across the 1 resistor. It samples the voltage drop across the resistor every 200 ms. The acquired data is then transmitted to a computer via USB, where it is stored. The current flow through the system is recorded for two transmissions after which the WiFi dongle is immediately removed so as to record the overhead of

> *V R*

<sup>1</sup> ∴ *I* = *V*

Finally, a survey is contacted to investigate the ergonomics of the proposed system. Questionnaires are given to eight people. The questionnaire investigated the six attributes of comfort proposed by James and Chris [38]. Their comfort scale consists of the following attributes: emotion, attachment, harm, perceived change, movement and anxiety. The participants are asked to use the hand glove and then they are asked to answer 12 questions. The questions

(3)

*I* = \_\_ *V*

the dongle itself.

250 Wearable Technologies

*<sup>I</sup>* <sup>=</sup> \_\_

**Figure 8.** Throughput of the proposed system.

**Figure 9.** Time response of Al-Yad.

flow of current is recorded after the dongle is removed. This shows that the energy overhead

**Emotion** 1.0000 0.6436 0.8205 0.6207 0.5691 0.6397 **Attachment** 1.0000 0.6517 0.7298 0.7685 0.5202 **Harm** 1.0000 0.6726 0.7477 0.5358 **Perceived change** 1.0000 0.7273 0.0309 **Movement** 1.0000 0.4969 **Anxiety** 1.0000

**Emotion Attachment Harm Perceived change Movement Anxiety**

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Power dissipated by the system can be calculated by multiplying the current in **Figure 10** by the voltage across the system (i.e., 5 v). This gives an average of 310 mW during transmission

Finally, a survey was carried out to access the comfort of the hand glove. **Figure 11** shows the result of the survey and **Table 3** shows the correlation between the different attributes inves-

comes from data transmission itself.

and 220 mW when the system is not transmitting.

**Table 3.** Correlation-coefficient matrix for comfort-ability of the hand glove.

**Figure 11.** Survey result for comfort-ability of the hand glove.

**Figure 10.** Current consumed by system while running.

**Figure 11.** Survey result for comfort-ability of the hand glove.


**Table 3.** Correlation-coefficient matrix for comfort-ability of the hand glove.

**Figure 10.** Current consumed by system while running.

**Figure 9.** Time response of Al-Yad.

252 Wearable Technologies

flow of current is recorded after the dongle is removed. This shows that the energy overhead comes from data transmission itself.

Power dissipated by the system can be calculated by multiplying the current in **Figure 10** by the voltage across the system (i.e., 5 v). This gives an average of 310 mW during transmission and 220 mW when the system is not transmitting.

Finally, a survey was carried out to access the comfort of the hand glove. **Figure 11** shows the result of the survey and **Table 3** shows the correlation between the different attributes investigated. Eight participants were asked about the comfort of the hand glove. The participants were asked about their experience based on: emotion, attachment, harm, perceived change, movement and anxiety [38].

**Author details**

Dhahran, Saudi Arabia

4258-4265

**References**

Farouq Muhammad Aliyu\* and Basem Almadani

\*Address all correspondence to: g201303650@kfupm.edu.sa

https://doi.org/10.1080/01969722.2017.1418708

Sensor Letters. 2014;**12**(9):1331-1336

(3CA 2013). Atlantis Press; 2013. pp. 449-452

Available from: http://dx.doi.org/10.1007/s12652-012-0114-2

Computer. 1999;**32**(1):57-64

2014;**5**(5):621-622

010-0032-0

Department of Computer Engineering, King Fahd University of Petroleum and Minerals,

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[10] Kikhia B, Stavropoulos TG, Meditskos G, Kompatsiaris I, Hallberg J, Savenstedt S, Melander C.Utilizing ambient and wearable sensors to monitor sleep and stress for people with bpsd in nursing homes. Journal of Ambient Intelligence and Humanized Computing

[Online]. 2015:1-13 Available from: http://dx.doi.org/10.1007/s12652-015-0331-6

Emotion is whether the user is worried about his looks or on the edge because of wearing the glove. Attachment is the feeling the user gets when the glove is moving around—that constant feeling the user gets of wearing something. Harm is when the user fears being harmed by the glove. Perceived change is when the user feels physically different as opposed to emotion which is a psychological difference. Movement attribute is the measure of the glove which affects the user's movement. Anxiety is the worry a user gets about the glove's safety and reliability.

The attributes were tested on a scale of 0–10, with 0 being least negative and 10 being the most negative experience. The results show that the overall discomfort of the glove is well below the scale of five (see **Figure 11**).

However, perceived change, movement and emotion show higher readings. To investigate further, correlation coefficient between the different attributes is computed. **Table 3** shows the correlation matrix between all the attributes. It can be seen that there is a very strong relationship between emotion and harm, which suggests that the user's emotion toward the device is due to the user feeling some kind of mild harm. This may be due to the flying wires and the printed circuit boards (PCBs) that were glued to the glove. Also there is strong correlation between attachment, movement and perceived change. This tells us that the user could not move well or he is afraid of moving because he feels that the glove is loose, which leads to the user feeling physically different. Harm is strongly correlated with movement restriction because the user feels mild pain, in addition to moving parts mentioned earlier.

In conclusion, the users show emotion, perceived change and movement restriction the most because of the way the glove was packaged. To improve the glove, Raspberry Pi may be replaced with a smaller SBC like Beagle Bone. PCBs should be covered with slim plastic casing before attaching it firmly to the glove. This will help prevent parts from falling over and reduce harm due to protruding electronic components and heat. Flying wires can be covered by a layer of fabric. This will also reduce the movement of the components on the glove.

### **6. Summary**

This chapter discussed our proposed intelligent glove designed to control actuators in an industrial environment setting. The glove is constructed using Raspberry Pi, a WiFi dongle and an assembly of light sources and light sensors. It was found that the system has a delay of approximately 23 ms, which is fast enough for controlling motors, pneumatic actuators and other mechanical actuators. Furthermore, the maximum power dissipated by the system is 310 mW, which showed that the system could be powered by a mobile phone's Lithium ion battery (3100 mAh) for up to 10 h of continuous data transmission. Moreover, a survey was carried out to investigate the comfort ability of the glove: It was found that the glove was acceptable but users have safety concerns and movement restrictions. This problem can be solved by repackaging the device.

### **Author details**

tigated. Eight participants were asked about the comfort of the hand glove. The participants were asked about their experience based on: emotion, attachment, harm, perceived change,

Emotion is whether the user is worried about his looks or on the edge because of wearing the glove. Attachment is the feeling the user gets when the glove is moving around—that constant feeling the user gets of wearing something. Harm is when the user fears being harmed by the glove. Perceived change is when the user feels physically different as opposed to emotion which is a psychological difference. Movement attribute is the measure of the glove which affects the user's movement. Anxiety is the worry a user gets about the glove's safety and reliability.

The attributes were tested on a scale of 0–10, with 0 being least negative and 10 being the most negative experience. The results show that the overall discomfort of the glove is well below

However, perceived change, movement and emotion show higher readings. To investigate further, correlation coefficient between the different attributes is computed. **Table 3** shows the correlation matrix between all the attributes. It can be seen that there is a very strong relationship between emotion and harm, which suggests that the user's emotion toward the device is due to the user feeling some kind of mild harm. This may be due to the flying wires and the printed circuit boards (PCBs) that were glued to the glove. Also there is strong correlation between attachment, movement and perceived change. This tells us that the user could not move well or he is afraid of moving because he feels that the glove is loose, which leads to the user feeling physically different. Harm is strongly correlated with movement restriction because the user feels mild pain, in addition to moving parts mentioned earlier.

In conclusion, the users show emotion, perceived change and movement restriction the most because of the way the glove was packaged. To improve the glove, Raspberry Pi may be replaced with a smaller SBC like Beagle Bone. PCBs should be covered with slim plastic casing before attaching it firmly to the glove. This will help prevent parts from falling over and reduce harm due to protruding electronic components and heat. Flying wires can be covered by a layer of fabric. This will also reduce the movement of the components on the glove.

This chapter discussed our proposed intelligent glove designed to control actuators in an industrial environment setting. The glove is constructed using Raspberry Pi, a WiFi dongle and an assembly of light sources and light sensors. It was found that the system has a delay of approximately 23 ms, which is fast enough for controlling motors, pneumatic actuators and other mechanical actuators. Furthermore, the maximum power dissipated by the system is 310 mW, which showed that the system could be powered by a mobile phone's Lithium ion battery (3100 mAh) for up to 10 h of continuous data transmission. Moreover, a survey was carried out to investigate the comfort ability of the glove: It was found that the glove was acceptable but users have safety concerns and movement restrictions. This problem can be

movement and anxiety [38].

254 Wearable Technologies

the scale of five (see **Figure 11**).

**6. Summary**

solved by repackaging the device.

Farouq Muhammad Aliyu\* and Basem Almadani

\*Address all correspondence to: g201303650@kfupm.edu.sa

Department of Computer Engineering, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia

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## *Edited by Jesús Hamilton Ortiz*

This edited volume *Wearable Technologies* is a collection of reviewed and relevant research chapters, offering a comprehensive overview of recent developments in the field of computer engineering. The book comprises single chapters authored by various researchers and edited by an expert active in the computer engineering research area. All chapters are complete in themselves but united under a common research study topic. This publication aims at providing a thorough overview of the latest research efforts

Published in London, UK © 2018 IntechOpen © golubovy / iStock

Wearable Technologies

Wearable Technologies