A passive infrared sensor (PIR sensor) is an electronic sensor that measures infrared (IR) light radiating from objects in its field of view. They are most often used in PIR-based motion detectors.

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.

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 ...