This pre-assembled sensitive ultrasonic motion detector circuit uses a quartz crystal to lock the detector frequency for maximum stability and reliability. It was originally designed to designed for use as a parking distance detector. It provides a digital, analogue and relay output. Features; Buzzer output: fast/slow/continuous. Distance indication with 3-LED-bar. Adjustable alarm distance. LED alarm indicator. Dry contact NO/NC relay. Applications: robot projects, object detection, distance measuring, parking aid, security systems, etc. Range: 0.66 to 8 ft. Frequency 40kHz. Operates on 12VDC/200ma. MG325