The PIR Motion Presence Sensor is a PIR sensor switch, utilizes the infrared energy from human as control-signal source and determine the light to need to work or not, and control the light on and off automatically .When one enters the detection filed and trigger the sensor to work ,the light turns on; when one leaves the detection filed and the setting time reaches, the light will turn off.It can detect the ambient light illumination automatically and set and adjust the value according to the fact need. Such as, the light will turn on and works when the ambient light illumination is under setting value. once it exceeds the setting value, the light will stop working.The light will be on until the time-delay comes when the sensor is triggered. Once detected the constant signal, the time will be overlaid and the light will be on constantly.It can be installed in indoor, corridor and public-building.