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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

   Motion sensors create zones which cannot be accessed without sounding an alarm. Most cameras do now have a motion detection function, with some brands having thermal detection so they only activate when sensing a heat signature. This function is used so cameras do not pick up false alarms from trees blowing in the wind. [11]

4. Wireless security camera - Wikipedia

   en.wikipedia.org/wiki/Wireless_security_camera

   Wireless security cameras are closed-circuit television (CCTV) cameras that transmit a video and audio signal to a wireless receiver through a radio band. Many wireless security cameras require at least one cable or wire for power; "wireless" refers to the transmission of video/audio. However, some wireless security cameras are battery-powered ...

5. 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.

6. Indoor positioning system - Wikipedia

   en.wikipedia.org/wiki/Indoor_positioning_system

   Any wireless technology can be used for locating. Many different systems take advantage of existing wireless infrastructure for indoor positioning. There are three primary system topology options for hardware and software configuration, network-based, terminal-based, and terminal-assisted.

7. Alarm sensor - Wikipedia

   en.wikipedia.org/wiki/Alarm_sensor

   In telecommunications, the term alarm sensor has the following meanings: . In communications systems, a device that can sense an abnormal condition within the system and provide a signal indicating the presence or nature of the abnormality to either a local or remote alarm indicator, and (b) may detect events ranging from a simple contact opening or closure to a time-phased automatic shutdown ...