- A device which senses movement, or a lack of movement, in a given area, enclosure, device, piece of equipment, or system. Such a device may detect movement through the use of sensors which utilize and/or monitor microwaves, infrared radiation, laser light, vibrations, temperature changes, magnetic fields, and so on. Used, for instance, for intrusion detection, to turn on lights in places where illumination is needed only when someone is present, or to ensure equipment is functioning. Also called motion sensor.
- synonymmotion sensor