ultrasonic motion detector
Ultrasonic motion detectors belong to the active motion detectors that emit an ultrasonic signal or an ultrasonic burst. The emitted ultrasound is reflected by objects, persons and liquids and is received and evaluated by the ultrasonic sensor.
If the ultrasound is emitted as a burst, the temporal course of the reflection changes due to the Doppler effect as soon as an object or person changes its position, i.e. moves.
Ultrasonic motion detectors are used in security systems and alarm systems and are based on the reflection of ultrasonic waves. These can be reflected multiple times in hallways, even around corners. Therefore, ultrasonic motion detectors can also monitor hallways that go around corners. To avoid false alarms, ultrasonic motion detectors must not be installed behind curtains, near air conditioning vents, or behind loosely hung objects.