220V PIR Motion Sensor is short for Passive Infrared Radiation, works based on infrared and motion technology. When the human body enters the sensing range, the switch microcomputer system can sense the infrared hydroelectric changes of the human body movement, and automatically turn on the lighting fixture at the same time, until the human body is sensed to leave and delays the preset time before turning off automatically. Human sensor switches are often used in stairs, walkways, toilets, elevators and many other general public places. The PIR Switch is the best solution for energy saving
link:http://www.hkram.com/sensor-switch/pir-sensor-switch/220v-pir-motion-sensor.html