Microwave Sensors

Doppler motion detector units, or microwave sensors, operate at frequencies of 10 Mhz. They utilize a doppler radar signal which bounces microwaves off of an object, then measures the frequency of the returning microwaves. If an object is moving in the sensor's field, the returning microwave will be at a different frequency, higher or lower than the original signal transmitted. Microwave sensors offer a greater distance of coverage and are more reliable at greater distances. Microwaves can also penetrate walls which means these security sensors can be placed behind objects.

A drawback to using microwave sensors in a home security setting is their strong sensitivity, which makes them hard to set or adjust effectively, and makes them vulnerable to interference from other electrical devices such as lighting and radios.

If microwave sensors are not compatible with your home situation, try these other types of sensors:

Infrared Sensors
Acoustic Sensors
Vibration Sensors
Photoelectric Sensors

Learn more about home security systems.