The presented schematic shows how to build a simple PIR motion sensor. PIR sensors allow motion sensing, it is almost always used to detect whether someone has moved in or out of the sensors range.

Let me introduce another simple microcontroller-based do-it-yourself circuit that detects motion and excites a light source in a flash. The “snooper” here is an ordinary passive infrared (PIR) motion ...

Fig 1. This version of the trigger circuit for the stop-motion camera system uses an electret microphone for a sonic input, but the designer can substitute an LED and photodiode pair to create an ...