motion detector
1 of 1noun/ˈmoʊʃən dɪˈtɛktər/
Forms:motion detectors
1
a device that detects the presence of movement within a specific area and can trigger an alarm or other action as a result
A motion detector is a device that senses movement within a specific area. It is commonly used for security purposes, activating alarms or lights when it detects motion. The detector works by using infrared sensors, ultrasonic waves, or other technology to sense changes in the environment, such as when a person walks by. Motion detectors are often installed in homes, offices, and public spaces to monitor activity or trigger automatic actions, such as turning on lights when someone enters a room. They help enhance security and energy efficiency by only activating when movement is detected.
- The motion detector in the hallway turned on the lights as soon as I walked past.
- The security system uses a motion detector to monitor any movement around the house.
- The motion detector alerted the homeowners when someone tried to enter their yard at night.
- The outdoor lights are connected to a motion detector, so they automatically turn on when someone approaches.
- The motion detector inside the store triggered the alarm when it sensed someone entering after hours.