A burglar alarm can provide extra security, acting as one more level of deterrent to burglars who seek easy entry. But they shouldn’t be considered burglarproof and are certainly no substitute for quality locks and security-conscious habits. The alarm system must be reliable and be used dependably by all family members. The consistent peel of false alarms will soon be ignored by neighbors. Police departments in many communities will not respond to an alarm unless summoned by an individual. Consider informing police in your area of the names of two key-holders in the event that the alarm is engaged.
There are two basic kinds of alarm system: passive types that detect an intruder’s presence in the home, and perimeter units that protect doors, windows, and other points of entry. A combination of features will provide the best protection.
A Typical Alarm System
The control unit is the central part of the system, since the detectors are attached to it and it is from the control unit that the signal is passed to a bell, siren, or other notification device. The control unit must be set to permit family members enough time to come and go. One option permits door contacts or sensors to be activated in selected zones, such as those on doors and windows in the downstairs portion of the house, while disarming sensors where family activity continues. A tamperproof control unit will prevent anyone from disarming it without the proper key or digital code. The control unit should have a rechargeable battery in case of power failure.
Magnetic contacts or detectors trigger the alarm when someone opening a door or window breaks the contact. Other types of detectors are sensitive to movement and vibration. To sense the difference between an intruder and ordinary, external stimulus, detectors must be installed and calibrated accurately.
The infrared sensors on a scan¬ning device detect movement in a wide expanse. One advantage is that they can be positioned to ignore the presence of pets.
Although usually connected to a central control unit, independent, battery-operated sensors are available.
A bell or siren installed on an outside wall is activated when signaled from the control unit. After a prescribed period of time, the alarm turns off. Some alarms contain lights that continue to flash; some automatically rearm. If you choose a burglar alarm monitored by a security service, a warning is transmitted directly to a monitoring center. No matter what type of alarm you choose, make sure that the alarm is triggered not only via detectors or scanners but also when any attempt is made to dismantle the alarm directly.
Do-It-Yourself Alarm Systems
There are several alarm systems available for the do-it-yourselfer. Before installation, check with the supplier of the equipment to ensure proper placement of sensors and detectors. Most important is that the control unit of the system be tamperproof. Wireless systems simplify installation as there is no need for extensive wiring; outbuildings can still be monitored. Self-contained systems plug into any outlet and can be moved as needed.
Automatic Timer Switches
An automatic timer switch— plugged into an ordinary electrical wall socket—can turn lights, radios, and televisions on and off, giving the outward appearance that someone is home at all times. You can set the program to turn appliances on and off several times throughout the day or night. Sophisticated models can be set for different times every day of the week.
A peephole lets you identify visitors before opening the door. Install a wide-angled viewer that permits you to see beside the door as well as the floor beneath it. Purchase a viewer that fits any door thickness.