Infrared Motion Sensors

These types of wireless sensors use the infrared light spectrum which is an invisible light that emanates from any heat source. Infrared sensors (passive infrared) compare the heat of any object passing through the secure zone to that of the background setting such as a wall, and/or measure the rate of change in temperature of an object. These sensors can detect fires or malfunctioning appliances.

Infrared sensors are cheaper than microwave sensors and ultrasonic sensors and are generally smaller and more reliable. Since they don't respond to sharp impacts, radio waves or vibrations they are commonly part of packaged home security system.

Some drawbacks to infrared motion sensors is that they don't cover a full room. The scanned area is really numerous linear areas, much like fingers pointing into the room. The areas between the fingers are not covered. Many systems come with a variety of lenses which allow the user to select the type of security coverage they would like to have for their secure zone.

Learn more about home security systems.