Burglar alarms systems work by sending an electronic signal to the monitoring company “command center”, over some kind of phone line, when some kind of trigger mechanism sets off the alarm.
The main kinds of trigger mechanisms are:
1. Door or Window Contacts – These are either hard-wired or wireless contacts which are made up of two parts. One part is on the door or window itself, and the other part is on the door or window frame.
As long as the door or window is closed, the two parts of the contact have no “news” to report, but as soon as the door or window is opened, the separation of the two parts says, “Hey! Hey! Somebody opened the door! [or window]”.
There might be a delay of maybe 30 seconds, depending on the mode the system is in, or it might be set on “no delay”. But either way, when any “delay” time is over, the siren is set off, and the burglar alarm send a signal in to the command center of the monitoring company.
2. The Motion Detector – Motion detectors are a vital part of a good security system, because you never know how a burglar might get into your home. They might come in a window, cut a hole in the side of your home, come in a heat duct, or some other oddball way.
The motion detector receives infra-red rays from a burglar, trips the alarm, sets off the siren, and sends a signal into the command center.
3. Glass Breakage Detectors – You may choose to have one or more glass breakage detectors installed in your home. They are small electronic devices that can “hear” the sound of glass breaking, as when someone breaks a window in your home.
This sound of breaking glass causes the detector to trip the burglar alarm, set off the siren, and send a signal to the command center.
So which parts are most important?
Well, you MUST have door contacts. That’s most important of all. Next in importance is the motion detector. You never know how a crook will enter your house.
I can’t stress how important it is to have at least a BASIC SYSTEM With door contacts and motion detector.
Don’t wait to get a basic burglar alarm system if you can’t afford “extras” like window contacts and glass breakage detectors! You can always get those later. But don’t go without security in the meantime.
If you can afford the “extras”, by all means get them.
Window contacts might cost you from $65 to $150 each, depending on whether they are hard-wired or wireless, and depending on the company you deal with and where you’re located.
Glass breakage detectors might cost $150 each (they vary widely – check with various companies). But one detector may cover several windows, depending how close together they are.