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2. Security alarm - Wikipedia

   en.wikipedia.org/wiki/Security_alarm

   The trigger signal from sensors are transmitted to one or more control units either through wires or wireless means, such as radio, line carrier, and infrared. Wired systems are convenient when sensors, such as passive infrared motion sensors and smoke detectors require external power to operate correctly; however, they may be more costly to ...

3. Home security - Wikipedia

   en.wikipedia.org/wiki/Home_security

   Door and window sensors are also implemented in most home security systems. One part of the system is installed on the door or window itself while the other part is installed on the frame of the door or window. The two part system connects securely when a door or window is closed, creating a security circuit. [5]

4. Driveway alarm - Wikipedia

   en.wikipedia.org/wiki/Driveway_alarm

   A driveway alarm always consists of two components, a sensor and receiver. The sensor is used to detect people or vehicles on the driveway and the receiver is the device which alerts the user or owner to this detection. Wireless driveway alarms consist of three components, the sensor, receiver and a transmitter which sends the wireless alert ...

5. Wireless security camera - Wikipedia

   en.wikipedia.org/wiki/Wireless_security_camera

   Wireless security cameras function best when there is a clear line of sight between the camera(s) and the receiver. If digital wireless cameras are outdoors and have a clear line of sight, they typically have a range between 250 and 450 feet. If located indoors, the range can be limited to 100 to 150 feet.

6. Door security - Wikipedia

   en.wikipedia.org/wiki/Door_security

   A metal doorframe with a strike plate built in: in other doors this would be a metal strikeplate in a wooden doorframe. The term door security or door security gate may refer to any of a range of measures used to strengthen doors against door breaching, ram-raiding and lock picking, and prevent crimes such as burglary and home invasions.

7. Photoelectric sensor - Wikipedia

   en.wikipedia.org/wiki/Photoelectric_sensor

   Conceptual through-beam system to detect unauthorized access to a secure door. If the beam is interrupted, the detector triggers an alarm. A photoelectric sensor is a device used to determine the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are largely used in ...