The Everspring HSP02 is a versatile Z-Wave compatible motion detector. It can be triggered by movement or changes in light level, allowing it to be used as a security and home automation sensor. The detector includes two sensors. PIR (passive infrared receiver) Monitors changes in infrared level and movement that indicate a persons presence. Once detected, the unit sends an alert to all the Z-Wave devices it is associated with. Light Level sensor Measures a room’s ambient light level (lux) allowing it to trigger an event when the light level is above or below a pre-set level. For instance, when the room is dark and movement is detected the unit signals to the controller to turn the room’s lights on – lights come on automatically when you walk into a room. The motion detector is battery-operated, an alert will be sent to the central controller and the units LED will flash when the battery level becomes too low. It also includes a tamper alarm that sends an alarm signal if anyone tries to prevent it working.