Motion Detection

Motion detection uses a motion sensor, to measure and calculate changes in an environment. An electronic motion sensor utilizes light and sound changes. Motion can be detected electronically by various means, including a light beam, active radar and microwave, and ultrasonic reflection. Passive motion detection is often achieved using infrared sensors. The type of motion detector on home security lighting is an example of a passive infrared sensor system.

A pyroelectric sensor is an example of a PIR (passive infrared) detector that is used with security lighting and indoor sensors for bugler alarms in many homes. This type of passive sensor is triggered by a rapid change in present infrared energy.