**2.2.2 Bluetooth RS232 adaptor**

The data communication between RFID reader and the smart phone is through Bluetooth. HL-MD08A (Bluetooth RS232 Adaptor manufactured by Hotlife Technology) is used in the presented system. It supports a wide range of Baud rates from 1.2K to 921.6K bps. Fig. 5 shows the picture of HL-MD08A, and Fig. 6 shows the picture of the RFID ring (tag) and the connection of HL-MD08A to the RFID reader.

Fig. 5. Bluetooth RS232 Adaptor

Fig. 6. Bluetooth adaptor, RFID ring (tag) & RFID reader

### **2.2.3 Biosignal recorder**

24 Health Management – Different Approaches and Solutions

The data communication between RFID reader and the smart phone is through Bluetooth. HL-MD08A (Bluetooth RS232 Adaptor manufactured by Hotlife Technology) is used in the presented system. It supports a wide range of Baud rates from 1.2K to 921.6K bps. Fig. 5 shows the picture of HL-MD08A, and Fig. 6 shows the picture of the RFID ring (tag) and the

Fig. 3. RFID ring (tag)

Fig. 4. RFID reader

**2.2.2 Bluetooth RS232 adaptor** 

Fig. 5. Bluetooth RS232 Adaptor

connection of HL-MD08A to the RFID reader.

The biosignal recorder, developed in this system for assessment of sleep depth and physical activities during daily lives, can measure electroencephalogram (EEG), electrocardiogram (ECG) and body acceleration signals. The size of this developed device (45mm *×* 25mm *×*  65mm, 62.5g) is more appropriate for ambulatory recoding than that of the well-known devices such as LifeGuard (Mundt et al., 2005) (129mm *×* 100mm *×* 20mm, 166g), AMON (Anliker et al., 2004) (286g) and Smart Vest (Pandian et al., 2008) (460g). Fig. 7 shows photographs of the developed device. The device consists of an analog part, a digital part and a power supply, as in Fig. 8.

The analog part has five electrodes. Two of them are placed on the forehead and ear lobe for EEG acquisition. Another two electrodes are patched on upper-right and lower-left breast for ECG acquisition. The last electrode is put on back neck for right-leg-driving. The acquired signals are amplified by instrumentation amplifiers (Analog Devices AD627) and operational amplifiers (Texas Instruments TLV2254). The amplification factors are 60dB for EEG and 46dB for ECG. These amplification circuits also have bandpass characteristics with the passband from 0.5Hz to 100Hz. Then the conditioned signals are sent to the digital part. The digital part consists of a mixed-signal microcontroller, an accelerometer and a memory card. The mixed-signal microcontroller (Texas Instruments MSP430F4270) converts the conditioned signals (EEG and ECG) to digital signals with 16-bit resolution at the sampling rate of 256Hz. This microcontroller also collects three-axis acceleration values from the accelerometer (Freescale MMA7456L). This accelerometer provides 10-bit digital values whose range and sampling frequency are *±* 8g and 8Hz, respectively. The microcontroller records these digital data into the memory card. The memory card can store digital data up to 2GBytes, large enough for 2-week recordings. The power supply provides regulated voltage to other parts. The power source is one-cell lithiumion polymer battery (3.7V, 900mAh) and connected to a voltage regulator (Texas Instruments TPS73130) through a diode-OR circuit. This diode-OR circuit enables us to hotswap batteries. The principal parts of the developed device is enclosed in an ABS plastic case (Takachi SW-65S) whose size is 45mm *×* 25mm *×* 65mm. The overall weight of the device is 62.5g. Since the current consumption is 29mA in the steady state, the device can record EEG, ECG and three-axis accelerogram for up to 31 hours with the fully-charged battery. Furthermore, the measurement duration can be prolonged up to 2-weeks when two or more batteries are used, swapped and charged alternately once a day.

A Mobile-Phone-Based Health Management System 27

The data controller consists of a MCU (Philips P89C51RD2HBP microcontroller), a multiplexer (Hitachi HD74LS153P, Dual 4-line to one-line Data Selectors), a demultiplexer (SN74LS156N, Dual one-line to 4-line Data Decoder), and a RS232-TTL voltage conversion IC (Intersil HIN232CP). Fig. 9 shows the developed data controller circuit on a breadboard. The function of this data controller is like a data switch to bridge the biosignal recorder and additional sensor to the Bluetooth adaptor. It alternately transmits the data from these two

Any smart phone which operating system is Windows Mobile 6.1 is suitable for the presented system. The smart phone used in this system is ASUS P552W with built-in GPS. It supports HSDPA 3.6Mbps/EDGE/GPRS/GSM 900/1800/1900. Fig. 10 shows the picture of

**2.2.4 MCU data controller** 

Fig. 9. MCU Data Controller

Fig. 10. ASUS P552W smart phone

**2.2.5 Smart phone** 

this smart phone.

different sensors to the smart phone via Bluetooth.

(c)

Fig. 7. Biosignal recorder (a) recorder with case closed, (b) recorder with case opened, (c) portable recorder with wires attached to user's body

Fig. 8. Block diagram of developed biosignal recorder
