Motion detectors and motion sensors are an important part of any burglar alarm, and can be installed inside or outside to make your property more secure. By integrating motion detectors with other security devices, such as surveillance equipment or security lighting, your security system can be customised to work intelligently, saving resource and energy.
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How do motion detectors work?
There are two types of motion detectors - Passive InfraRed (PIR) and microwave. PIR detectors monitor the infrared radiation emitted by all objects within their field of view. A PIR detector will alert your security system when it detects movement of a source of infrared radiation against background radiation levels.
Microwave detectors transmit an electromagnetic signal and compare the reflected signal from all objects in their field of view. A moving object is identified using the Doppler effect comparing transmitted and reflected signals. If the signal matches preset detection criteria an alarm is triggered. Microwave detectors are much more sensitive to movement than PIR detectors, but can be prone to false alarms if not properly installed as their detection can pass through walls.
In most applications, PIR detectors provide excellent protection. In some hostile environments PIR detection on its own may not be suitable as it can be sensitive to thermal radiation interference. Microwave detectors on the other hand can be sensitive to radio interference. Motion detectors which combine PIR and microwave detection are called 'dual-technology' (or 'dual-tech') and are relatively immune to interference. Consequently, they have a low false alarm rate as both technologies have to detect simultaneously in order for an alarm to be triggered. Dual-tech sensors also provide the additional benefit of anti-masking functionality.
What sort of motion detector is right for me?
Motion dectors and motion sensors can be simple and inexpensive or more complex, providing tolerance to pets and other animals. They can be suitable for indoor or outdoor use, hard-wired to your burglar alarm or wire-free. You may want to only detect movement in certain 'zones' of your property, or integrate them with other security devices such as perimeter security, CCTV cameras or security lighting. In more sensitive commercial environments or where high-value property needs to be protected, the required grading of an intruder alarm system will determine the use of dual-technology motion detectors.
Whatever your requirements, because we’re vendor-neutral and are constantly reviewing the range of the motion sensors and detectors on the market, you can be certain that we will recommend the best motion detectors for your security system based on your budget and how you use your property.
Talk to a qualified intruder alarm and motion sensor engineer
Chris Lewis Fire & Security engineers integrate motion sensors and motion detectors as standard into our intruder alarm systems according to the individual needs of our customers. To discuss your requirements for motion detectors, or for replacement parts, or just some straight-forward advice from a qualified installer, get in touch with us.