Technology has taken home security into the 21st century with the advent of video cameras and infrared detection systems. Motion detectors are perfect solutions for home security as they are economical to buy, easy to install and are highly effective in delivering an element of surprise for any would be burglar. However, infrared takes this one step deeper by allowing not only the detection of burglars but the ability to monitor them without their knowledge.
Burglars work under cover of darkness usually and infrared detection give us the ability to ‘see’ in the dark. This particular system is called Infrared light sensor or PIR sensor. They work by radiating an infrared light at an object in their sight line. When someone or something passes in front of this sight line a change in temperature is sensed. It senses this change in temperature as motion and activates.
These highly versatile infrared motion detectors can be used in a variety of uses and for many types of advanced recognition systems.
Placing infrared motion detectors
If being used as part of a home alarm system PIRs should be installed inside rather than out in front of doors and windows. When motion is detected they will set off an alarm. These sensors can be remotely controlled or set manually via a keypad.
When PIRs are installed outdoors they are usually connected to outdoor lights. You can install a range of lights around the outside and perimeter of your home which are triggered by motion. Often this simple activation of lights is enough to scare off many burglars. They also act as a means to prevent anyone from hiding in a dark place in wait for you when you step outside. They are energy efficient and very practical and are often sufficient enough to chase away trespassers.
How they work
The technology used is called passive infrared. Mounted to a wall or window it sends out invisible ‘rays’ in several layers. The top layer reaches the furthest covering about 60 feet ahead and 35 feet out on either side. The center beam spreads covers an area roughly mid way and the bottom layer covers the area closest to the detector. Individually these beams measure the temperature of whatever they are detecting and wait for anything that changes causes a change in temperature. This change in temperature is considered motion and when detected they activate whatever they are connected to. This may be an alarm, a light or a video camera.
Inserted in the passive infrared detector is a microchip which allows easy adjustment for slow and methodical temperature changes. What this means is that as the room warms up and cools down the unit will recognize this and not send out a false alarm.
The variety of models available depends on the application. For instance some models are designed for ceiling mounting while other are recessed and in this way be disguised to look like something else.
Infrared motion sensors cannot protect every inch of your property and for this reason are often placed in areas considered security risks. They should be placed in locations that will allow the most coverage and in places where they cannot be tampered with.
Dual technology infrared motion detectors are available on the market which means that two separate technologies are in one device. These systems are generally used in areas where harsh environments reside such as a garage. Besides detecting temperature changes these motion detectors can also detect movement.
Pet owners can take advantage of the wonderful advances in technology because infrared motion detectors allow pets to roam free without activating. These systems consist of two sets of beams that are slightly offset from each other. A pet must hit the two beams simultaneously in order to activate it. In pet sensors the middle and bottom beams are pet immune while the top layer isn’t as pets generally operate ‘under the radar’ so to speak.
Buy infrared motion detectors
When it comes time buy infrared motion detectors it is suggested that first you decide where you need to place them and then decide on how much you want to spend. Placement is important as it can help calculate what your coverage will be and from that you can work out your budget.