Information about PIR Detectors.PIR Detectors (passive infrared) a.k.a. PIR Sensors.Any modern home security system will most likely include at least couple of PIR detectors. These detectors, or sensors, are a very common way of detecting movement, and with a security system the movement that needs to be detected is that of an intruder. All mammals emit heat, and that includes burglars, so a device that can identify a change of heat moving across a specific area can supply a means of detecting an intruder, a passive infrared sensor is such a device. When the sensor registers a change, which can be set to certain parameters, it sends a signal to the security system’s alarm unit. The sensor must identify a measurable change in the normal level of heat within the area of its surveillance, it must know what normal is and then send a signal when the level of heat changes, such as when a burglar moves within it. A PIR detector should be set to ignore slow changes, such the heat of the sun gradually warming up a room, and thus prevent many false alarms. To further reduce false alarms, caused by an increase in heat other than from a moving body, many passive infrared sensor units rely upon two sensors monitoring two side by side areas. In this case the alarm signal is not sent unless heat movement is detected across one, then the other area. If you have a pet you will not want your home security system kicked into action by your dog or cat walking across the motion detector’s surveillance area. Pet immune detectors are available that provide a pet ally, this means they are set to ignore movement below about 16 inches from the floor. These work well providing that your pet does not jump up onto furniture that is within the detection area. Pet immune detectors for larger pets are available but the snag here is that a savvy intruder could crawl on his belly, like the snake that he is, and avoid detection.
PIR Detectors – The Lens.The detector unit will have a plastic lens covering the sensor device, this will be a Fresnel lens that compresses the light passing through it, this is to concentrate the field of detection. An infrared motion sensor without a Fresnel lens would detect heat changes from a very wide field and it would be difficult to effectively monitor a given area. Most detectors tend to concentrate the light so that it is horizontally sensitive and so is best at detecting movement across an area. Some PIR detectors are available that are better at detecting vertical movement. Motion Detectors should not be your only intrusion defense.Passive infrared sensors, as good as they are, should not be your only method of detecting intruders, they should be used in conjunction with window sensors, door sensors and glass break detectors. As most PIR detectors are configured to identify a change of heat moving across a specific area, it is just possible for a burglar to fool the sensor by walking directly towards it rather than across it. It is also possible to pass a PIR motion detector, and not trigger the alarm, by moving exceedingly slowly but it would have to be at a snail’s pace. As part of your home security system PIR detectors provide an affordable and effective method of beating the burglar. © copyright surveillanceforsecurity.com Most homes have a room or a large closet that can be converted into a safe room (a.k.a. panic room.) Many homeowners are seeing the advantage of a secure safe room within their home. There is no doubt that homes protected by a home security monitoring system are far less prone to be burgled. Many insurance companies give a discount for homes defended by monitored home security. Even if you only use some of these top ten tips you will go a long way to make a burglar a very happy bunny.
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