"motion detector"的定义和意义

What is a "motion detector"?

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.