[ladyada] has a freshly-published and amazingly thorough tutorial on passive infrared (PIR) motion sensors. Most often seen in security floodlights and automatic doors, in creative hands these sensors ...

Passive InfraRed sensors (PIRs) are electronic devices which are used in some security alarm systems to detect motion of an infrared emitting source, usually a human body. All objects, living or not, ...

Recently, I exhausted my stock of common passive infrared (PIR) motion sensor modules and was looking for a new one to play with. I searched the web for a small type with self-contained electronics.

Unlike infrared optical sensors that use an LED transmitter and IR receiver, the PIR emits nothing. As its “passive” name suggests, it responds only to infrared energy radiated by the object being ...

An Infrared close object sensor installed on an industrial vehicle detects objects or pedestrians located in a hazardous area. When it detects a problem an audio/visual indicator makes an alert, that ...

In this YouTube video, the team from Mythbusters try to beat a thermal intrusion security sensor (a passive infrared sensor, aka PIR, that detects thermal differences). See how many attempts and what ...