An electronic system designed to detect unauthorized entry into or within a premise. The system may be activated by the closure of a switch (for example, by stepping on a mat, opening a window, etc.), by the interruption of a photoelectric beam, or by a motion detector.
A Intruder Alarm is a system designed to detect intrusion – unauthorized entry – into a building or other area. Security alarms are used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders. Security alarms in residential areas show a correlation with decreased theft. Car alarms likewise help protect vehicles and their contents. Prisons also use security systems for control of inmates.