Here at http://y2eeeprojectgroup1.blogspot.co.uk/ you'll find the blog for our year 2 project titled "The Detection of movement of human body by Pyroelectric infrared sensor", by Qizhen Sun, Xiaohan Lyu and Yikun Huang, supervised by Dr Joseph Yan.
The project is an detection system for detecting the movement of human body so that the system can alert when through the movement of human. With the PIR can sense the infrared ray proposed by human body and transfer the signal into electrical signal, the system is used for infrared
warning device, which demonstrates in bank alert system and monitoring services. Hence, we are expected to realize the function of inner device by constructing the PIR circuit.
Given that the input signal produced by PIR is very small, so we planned to use three stage amplifiers to amplify the input signal. The first stage amplifier will produce a sine wave on oscilloscope after the movement of human body. The second stage amplifier will amplify the signal
produced by first stage amplifier. Finally, the third stage amplifier as a comparator to rectify the sine wave signal into a rectangular wave to output. In addition, the detection distance is about 1 meter away when a Fresnel lens covered pyroelectric infrared sensor.