First let's discuss the hardware. The sensor selected for this design is the Glolab (www.glolab.com) PIR325 dual element pyroelectric sensor. There are a number of different PIR sensors available, ...

This is a simple update to Mr. Hareendran’s PIR Sensor Security Light circuit. It has a shortcoming limits the relay voltage to approximately 3.3V. While this may function with some 5V relays, it will ...