What is a Motion Activated Sensor?

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  • Written By: Troy Holmes
  • Edited By: W. Everett
  • Last Modified Date: 10 August 2019
  • Copyright Protected:
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Many homeowners use security surveillance systems in an effort to protect their personal valuables. A motion activated sensor is a device within a security system that detects a change in physical surroundings. This sensor can be attached to lights, alarms, or video cameras as an activation device for security systems.

A motion activated sensor detects any motion within a specific perimeter. Once a motion is detected, the sensor can activate secondary security measures including alarms, lights, or video surveillance. These sensors are typically sensitive to wind, animals, trees, and human traffic.

Many commercial banks use motion detection systems to monitor vaults and secure areas in the bank. These alarm systems use the technology of motion activated sensors. If the motion activated sensor detects an intruder within a secure area, an automatic alarm is sounded and law enforcement officials are notified.

A motion activated sensor works by sending out a beam of light, a radio wave, or a sound wave. This wave is used as an invisible perimeter security device. If anything breaks the beam after it has been engaged, it will trigger a message back to the device. These sensors are typically tied to computers, lights, or alarm systems.


Many homes have external lighting that uses a motion activated sensor. The external lights on a garage, porch, or patio can use a motion detector to deter criminals and save energy. Typically a motion detector light will automatically turn on when something passes through the yard or near the home. This is a convenient lighting source on garages because the lights will automatically engage when the homeowner approaches the garage.

Some home security systems use a vast area of flood lights that illuminate the entire home. These flood lights can be triggered through motion detectors. A motion detector can be placed in an obscure location where it is difficult to find. Once an intruder trips the detector the system can engage all external flood lights.

Motion detectors are also a common safety device for most garage doors. These sensors are placed directly below a garage door to ensure objects are free from the area when the door closes. If an object triggers the motion detector when the garage door is closing the sensor sends a stop request to the door system, which cause the door to stop closing. This is a critical safety feature for garage doors because without it the door would continue closing.



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Post 1

Motion lights are great security measures, since it may be hard to detect whether they have come on because of a movement, or because someone heard something outside and turned the light on. They have really come down in price and are not very expensive these days.

Motion detectors for electric garage doors are a fairly recent innovation, but they are so good for homes with children, who might get trapped underneath a closing door. These sensors usually work very well and will stop and reverse the door, if anything is detected in the path. I wouldn't install an electric garage door that didn't have this feature.

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