**2.10 Working principle of non-contact sensors**

Non-contact sensors detect changes in physical environmental conditions without physical contact with the measured object. There are several types of non-contact sensors, including optical, capacitive, magnetic, ultrasonic and many other types of sensors.

The specific working principle of non-contact sensors can vary based on the type of sensing pattern; however, they all depend on detecting changes in the environment, converting the required information into electrical signals which can be processed or analysed.

Manufacturing process of non-contact sensors.

Non-contact sensors are manufactured using a variety of different technologies depending on the specific application and the type of sensor being produced.

**Optical sensors:** Optical sensors use light to detect changes in position or distance. They can be made using a variety of.

## **2.11 Applications of non-contact sensors**

The field is progressing thanks to innovation. Active-matrix flexible temperature sensors and self-powered flexible temperature sensors are two examples of flexible

temperature sensors that have recently been studied and optimised. Flexible temperature sensors also include flexible thermocouples, flexible thermistors, and flexible thermochromic types [26].

Patients' temperatures have been monitored using printable, flexible sensors with excellent sensitivity. There is a trend toward creating wearable sensors that can measure temperature, avoiding conventional problems with heavy equipment and measuring inaccuracies caused by a variety of factors such as the wearer's movement.

Other prominent research in the field of non-contact infrared temperature sensors is recent work on creating a low-cost, more accurate Arduino-based infrared thermometer for body temperature detection. Arduino is an open-source electronics platform that converts input to output. This research aims to circumvent the problems inherent with non-contact infrared sensors currently on the market [26] (**Table 2**).

## **Advantages of non-contact temperature sensors.**


#### **Examples of non-contact temperature sensors**

