Figure 1 shows a way to control a light (or other 120-V ac appliance) with a passive-infrared (PIR) alarm sensor. The original concept was to turn a closet or shop light on whenever someone went into.

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 ...

State energy codes in the United States, which must be at least as stringent as the ASHRAE/IES 90.1-1999 standard, require automatic shutoff of lighting in commercial buildings greater than 5,000 ...