Motion detectors are designed to detect moving sources of heat in their detection area and to automatically switch the light according to the ambient luminosity.
This is achieved by means of passive infrared technology, where built-in infrared sensors register thermal radiation and convert this into an electrical signal. The sensor itself does not emit any radiation and is therefore referred to as a passive infrared sensor (PIR sensor).
Bodies, such as the human body, emit thermal radiation; this thermal radiation is in the infrared range and is not visible to the human eye. In view of this, if temperature differences occur due to movement, these will be detected by a sensor integrated in the motion detector and converted into an electrical signal. This is evaluated by a processor and then triggers the switching operation for the connected load.