Review on Motion Detector Working Operation

Detecting Motion

Motion detector emits radio energy into a room and monitors the reflection pattern

Basic motion detectors are fairly common these days and usually being implemented in automatic doors for example. There are several different sorts of detectors. An automatic door opener is an example of a radar-based motion detector. The box above the door sends out bursts of microwave radio energy (or ultrasonic sound waves), and then waits for the reflected energy to bounce back. If there is nobody in front of the door, the radio energy will bounce back in the same pattern. But if somebody enters the area, the reflection pattern is disturbed. When this happens, the sensor sends a signal and the door opens. In a security system, the sensor sends an alarm signal when the reflection pattern in a room is disturbed.