Description: A motion sensor is a type of occupancy sensor that is used to reduce power consumption in empty areas or to increase convenience to the user by switching on the lights on approach instead of switching them on manually. There are fixtures that incorporate motion sensors, or the sensor can be adapted to an existing lighting system. The most usual are passive infrared (PIR) sensors that are also used in security systems. Motion sensors for lighting may contain a light detector that prevents activation while daylight is present.