What is a PIR sensor ? A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors.
What does it do ? It can detect warm moving objects. Like, Humans or animals walking near it.
How does it look like ?
Does PIR sensor detect static warm objects ? No . It can only detect warm and moving objects.
Does PIR sensor give you a sense of direction ? No. They do not. But, you can always have multiple sensors in place and find the direction by checking the order they fire up.
How do they work ? A Basic PIR sensor in the market will output a high signal for a fixed amount of time, once a movement is detected. This time can be configured by a potentiometer on the back of the PIR sensor. If this potentiometer is turned all the way to the end anticlockwise, the output signal time will be a few seconds and the time increases as it is turned clockwise. At the max the time will be for a few minutes (Varies by manufacturer but mostly 7-10 minutes). The other potentiometer is for the sensitivity. This can be left in the middle for normal household projects.
What are we going to build ? A system HID device that can detect motion to perform a particular action, in this case put the system sleep or wake it up.
Below is the circuit diagram
Link to the Github project: Pir HID