Security Systems Information

Wiring

• Most security systems consist of individual sensors covering the doors and windows, motion detectors monitoring key areas like the living room or back yard, and a central control station allowing you to activate and deactivate the system. All of those components need to be connected for the system to work, usually in one of two different ways. Hardwired systems link them all with electrical cables, run through the walls of your home. Wireless systems, on the other hand, rely on radio signals to stay connected, and often use self-contained batteries rather than the house's electricity system. In addition, some security systems are entirely self-contained, consisting of one single unit which monitors the whole house.

Alarms

• Alarms work well in security systems because they're very easy to trigger. Typically, a magnetic switch in the door or window is turned on when the entryway is breached, either sending electricity to the alarm or cutting it off. The exact nature of the alarm depends largely upon the expense of the security system as a whole. The simplest alarms emit a loud noise, intended to alert people in the house (and/or neighbors) as well as scare away burglars. More sophisticated models can be linked to smoke detectors and activate the alarm in the event of a fire. The most reliable security systems alert the authorities, either by calling 911 and playing a prerecorded message or letting a private security company know that there is trouble in the home.

Sensors

• Sensors operate along several specific configurations, including heat, light and movement. Light-based sensors are usually the simplest. They consist of a single beam shining across a key area (such as a doorway or stairway) and into a sensor. When the beam is broken--say by someone stepping across it--it triggers the alarm. Movement sensors are much more sophisticated; they send ultrasonic signals out into a given area, which bounce back after striking walls, furniture or other objects. If someone enters the space, the signals bounce back more quickly after hitting his body, which sets off the alarm. Finally, infrared sensors note the overall temperature of the area. If a warm body enters it, the sensor detects the heat signature and sets off the alarm.

Outdoor Sensors

• Outdoor sensors work much the same way indoor sensors do. The only difference is that they must cover a wider area, and they only infrequently utilize sirens. Instead, many outdoor sensors turn on security lights, which illuminate the entire area and leave the burglar with nowhere to hide. Not only does that provide good security, but it prevents the homeowner from having to deactivate the system if it is triggered by a deer or neighborhood dog.

Control Panels

• Control panels coordinate the entire system: they activate the alarm when a sensor is breached, send power to the various components (with wired systems) and let the owner turn the system on and off. Control panels need to balance convenience with secrecy; placing them near a main entryway (the front door, for instance, or the garage door) allows the homeowner to activate it easily. On the other hand, prominent placement can alert burglars to its presence. Placing it in an unobtrusive locale near the door--in a closet or behind a panel--often makes the best solution.