Security Alarms: Passive Versus Active Infrared Sensors

When it comes to security alarms in general, and sensors in particular, both active and passive infrared detectors work well to protect residential and commercial properties. There are major differences in how they work and this will affect which one you choose to enhance the security at your home or business, as we’ll explain in this post.

What Is A Passive Infrared Sensor?

All objects, living or not, emit a certain amount of infrared radiation. Passive infrared sensors can pick up traces of this radiation even though we as humans can’t see it. These security devices use a pair of pyroelectric sensors to efficiently detect radiation - also known as radiant heat energy - in the environment in which they’re placed. These sensors are situated next to one another and when the signal differential changes between the sensors, the security alarm is activated.  

To the relief of pet owners, these sensors can be set to only go off when larger amounts of heat radiation are detected - usually from a human intruder. This makes them ideal for back yards where small dogs and cats can roam without setting off an alarm every 10 seconds.

A passive infrared sensor has several other benefits; the circuitry is simple and therefore reliable, the power consumption is low, and features can be easily applied across devices.  

What Is An Active IR Sensor?

Active infrared sensors are excellent at detecting any general movement in a given environment. This sensor requires an emitter and receiver only. The IR emitter sends out a beam of light to an in-line receiver. If the receiver does not see the IR beam, it detects that an object is between itself and the emitter - like an intruder walking in its path. The alarm is triggered as a result. 

This type of alarm is commonly used in businesses where no movement is expected at night. However, for a family home where pets like to wander, they might not be the best choice as they detect pure movement instead of radiation.   

Still Undecided On The Best One For Your Property?

Whether passive or active, each type of sensor is effective in detecting unexpected intruders and triggering security alarms as a result. For more information on passive as well as active infrared sensors, plus our range of security alarms and other security solutions, consult with the experts at Integrated Security Systems . We offer affordable security solutions, professional service and expert advice. Contact us today!