This sensor module has been designed as an alternative to the common PIR motion sensors widely used in burglar alarms and security lights Like the PIR sensor this sensor also detects only movements within its detection range But instead of sniffing the black body radiation from a moving person this sensor uses a microwave Doppler radar technique to detect moving objects It has a sensitivity range of 7 meters When triggered its TTLlevel output OUT pin will switch from LOW 0 V to HIGH 33 V for a finite time 2 to 3 s before returning to its idle LOW state