How Does a Movement Detector or Motion Sensor Work to Protect Your Security?

A motion sensor or movement detector is a device that senses movement to help raise the alarm if an intruder breaks into your home. This ability means that a motion sensor can play a key part in your home's security system.

How Does a Movement Detector Work?

There are several different types of motion sensors that you could use as part of your home security system.

Microwave Motion Detector

This type of detector emits high-frequency radio waves that are reflected by objects in their path. It can sense any change in the pattern of these waves. The movement of an intruder in the room will disturb the pattern, and the motion sensor will raise the alarm. Because a microwave detector is highly sensitive, it can be prone to false alarms. For home security use, it is often combined with another type of motion sensor.

The Passive Infrared (PIR) Motion Sensor

All living things give off infrared radiation, and this type of detector works by monitoring the levels of infrared radiation in the protected zone. If an intruder enters the space, the motion sensor will detect a change in temperature and trigger the security alarm.

The Ultrasonic Motion Detector

This type of detector has two parts: a transmitter that sends out very high frequency sound waves, too high for the human ear to hear, and a receiver that picks up the waves as they are reflected from the protected area. The motion of an intruder in the space between transmitter and receiver will change the frequency of the sound and trigger the security alarm.

Regardless of which type of motion detector is best for you, the one you choose can help increase your home's security.