+A **motion sensor** is an electronic device that detects physical [Movement](/wiki/movement) or presence within a specific range. Utilizing technologies like [Infrared](/wiki/infrared) or ultrasonic waves, it perceives changes in its environment, often triggering an alarm, light, or other automated response. These sensors are fundamental to security systems and energy efficiency.
+## See also
+- [Sensor](/wiki/sensor)
+- [Alarm](/wiki/alarm)
+- [Automation](/wiki/automation)
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