A motion detector alarm is a security system that activates when it senses movement. They are most commonly used in home and business security systems and provide protection against unwanted intruders, such as burglars.
Though all motion detector alarms work by sensing movement, there are several different ways they can do this. This results in different levels of performance which affect their suitability for your home's protection.
So, if you thought it would be easy to decide which one to install, think again!
To help you out, here are five of the most commonly installed motion detector alarms installed in homes along with some pros and cons. Enjoy!
Active Infrared Motion Detector (IR)
Active infrared motion detectors use a source and a sensor to detect movement. When the sensors can't detect the source then the alarm will activate.
These alarms are generally better as invisible trip wires or door alarms.
Passive Infrared Motion Detector (PIR)
Unlike its active sister, the passive infrared motion detector does not need to generate its own infrared light.
Instead it uses a sensor to detect heat generated from whatever is placed in front of it, which it senses as infrared light.
If a person walks in front of it then it can detect the heat change and activates the alarm. Unfortunately, some PIRs can't distinguish between human and animal as both give off similar infrared signals.
This is why pet friendly alarms have been invented. These alarms usually utilise two different infrared sensors which must be activated in unison to set off the alarm. One is targeted around shoulder height and the other below the waist. This way if a dog or a cat walks past, they only activate one of the sensors and therefore don't set off the alarm.
These are the most common household detectors.
Continuous Wave Radar Motion Detector (CW)
These are another type of active detector, meaning they use both a source and a sensor to detect motion. The source uses microwave signals to emit frequencies that reflect off surrounding objects. When an object moves, such as a person, the frequencies are disrupted and the alarm activates.
Often called microwave motion detectors, they are able to sense subtle changes in movement and are more reliable over long distances though tend to be more expensive than PIRs.
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Ultrasonic Motion Detector
Typically used in automatic doors, these detectors aren't the most reliable on the market. Usually an active sensor, they emit ultrasonic sound waves and listen for them to return. When something moves it changes the way that these sounds are echoed back to the sensor and the alarm activates.
Vibration Motion Detector
As you probably guessed, these detectors work by sensing vibrations. These detectors are often placed in vaults and walls to sense drilling or hammering. When the vibration reaches the sensor an electrical charge is created and this activates the alarm.
Getting The Right Motion Detector Alarm For Your Home
There are so many considerations to take into account when you're choosing your motion detector alarm, which is why we'd always recommend going to the professionals.
A professional will install the correct type of alarm in the right place, giving you a security system that's far more reliable than if you tried to install it yourself.
At Spy, our engineers have been installing motion detector alarms for [spy-age] years. They have the experience needed to ensure your system is fully optimised for your home.
We offer a free home security review where our engineers will find a solution tailored to your exact needs, so you don't have to worry about the risk of a home invasion.