Crystal-lock Ultrasonic Motion Detector
A pair of 40 KHz ultrasonic transducers detects moving objects or human bodies up to 10 meters. When an object is moving in front of the transducers, the detector responds by energizing the relay (LED on) for about 2 seconds. This will repeat continuously until the object stops moving. The transducers are mounted off board via 2 pairs of cables (as shown in the picture ) Plastic enclosure provided for the main board
Applications : Add-on motion detector for existing security alarm system, proximity switch, visitor chime (when used with door chime), . .