The KMY 24 is a microwave rader motion sensor based on the Doppler effect. It transmits a low energy microwave radiation at 2.45 GHz which is reflected by objects. If the object is moving relative to the sensor, a Doppler shift occurs. The shifted wave is mixed with the original wave in two mixers, resulting in two output voltage signals. The phase shift between these two signals is negative or positive depending on whether the target is approaching or receding from the detector. Features