Here is one simple circuit of a general-purpose white LED security light with Passive Infrared (PIR) Motion sensing mechanism. At the heart of the circuit is a PIR sensor module SB0061. SB0061 is a ...

PIR sensors are used to detect motion for example to turn on or off a light bulb when motion is detection. One such sensor is HC-SR501 motion detector, which costs around $1, and is tiny (32 x 24 mm), ...