Car alarm Car alarm A car alarm is an electronic device installed in a vehicle in an attempt to discourage theft of the vehicle itself, its contents, or both. Car alarms work by emitting high-volume sound (often a vehicle-mounted siren, klaxon, pre-recorded verbal warning, the vehicle's own horn, or a combination of these) when the conditions necessary for triggering it are met. Such alarms may also cause the vehicle's headlights to flash, may notify the car's owner of the incident via a paging system, and may interrupt one or more electrical circuits necessary for the car to start. Although inexpensive to acquire
Infrasonic burglar alarm Infrasonic burglar alarm The infrasonic burglar alarm reacts to shock waves in the air that are produced by a break-in. When an intruder tries to break a window or force open a door or a window, the resultant air pressure variations (or shock waves) produce sound vibrations in the air, from 0.1 – 50 Hz. These low frequency sound vibrations are captured by a very sensitive receiver in the alarm and converted into electronic signals. These signals are then passed through a pre-programmed electronic filtering system for analysis and when found positive, activate the alarm siren immediately; thus dissuading the