Home Surveillance Systems

For those who have more to guard than just a few Target-brand lamps and an Ikea table (though there's nothing wrong with either), home surveillance systems offer more extensive protection than door-mounted alarms. While the 10-dollar alarm is great as a basic deterrent, it may also be bested by nothing more than scissors or wire-cutters, both of which thieves tend to carry. A door mount may also be shattered with a strong elbow, knee, foot, or foreign object, rendering it (the alarm, not the anatomy) useless.

A home surveillance system may employ closed circuit alarms around the perimeter of the house, but it tends to include interior signals as well. The advantage here is that such systems can detect movement over a wide area and don't rely on a specific trigger the way a circuit-based alarm does. In fact, you can equip an entire room or floor of your house with wide-area detection that doesn't have to cost thousands and thousands of dollars.

Motion Detectors

Without a doubt, motion detectors are the most common form of wide area alarms for several reasons. One, motion detectors may be installed anywhere, from living rooms and dens to bedrooms and bathrooms. They may be placed high up in ceiling corners, down by the floor, at waist, chest, or head level, you name it. Further, they may be purchased and set up individually or as part of a bigger system. It's entirely up to you.

Motion detectors work on a similar principle to that of door-mounted alarms--the broken circuit. In this case, however, the circuit is created by a light source and the sensor that receives it and emits a return signal, thereby letting the source know that the light is traveling to and fro in an uninterrupted fashion. Once something, say, a human body, comes between the source and the sensor, that circuit is broken and the relay tripped.