Types of Burglary Alarms

Siren Sounder

• Some alarms have a siren that can alert anyone nearby that a sensor connected to the alarm has been set off. Sirens can have flashing strobe lights as well. These alarms are usually installed in plain sight to deter any burglar. These alarms are usually installed out of reach -- at least 12 feet high.

PIR Sensors

• A PIR or passive infrared device is one of the most common ways used for detecting movement. This type of device can detect rapid change in temperature by monitoring energy in the form of heat or infrared radiation. All living things give off infrared energy. These devices cannot detect gradual changes in energy.

Magnetic Switches

• Magnetic switches are ideal for protecting doors and windows. These devices are less expensive than other alternatives and are relatively simple to install. The magnetic switches contain two parts, a switch and a magnet. The switch is comprised of a loaded contact that closes and conducts an electrical circuit when the magnet is applied to the contact. The magnet is close contacts when the window is closed, which completes the electrical circuit. When the door or window is opened, the circuit is broken, which sends a signal to the control unit.

Ultrasonic Detectors

• Ultrasonic detectors use high-frequency sound waves to monitor movement. The sound waves will bounce off different objects in the room until the frequency is stabilized. A burglar breaking in will interrupt the sound waves and cause the alarm to go off.

Microwave Detectors

• Microwave detectors operate like ultrasonic detectors but use high-frequency radio waves rather than sound waves. These alarms can penetrate through walls and monitor nearby areas, unlike ultrasonic devices.

Considerations

• Some burglar alarms are silent and others are audible. The silent alarm will send a signal to a different location, such as a security center, to alert monitors that there has been a disruption in the alarm. The audible alarm will sound an alert to those nearby that there has been a break-in. Many audible alarms also contact a security center.