motionsensing

Motion sensing refers to the detection and measurement of movement or changes in position, typically using sensors that respond to heat, sound, light, electricity, or camera imagery. Systems can be passive, detecting signals in the environment, or active, emitting energy and analyzing reflections. The field originated in the mid-20th century with infrared detectors and radar, and modern motion sensing often relies on sensor fusion and computer vision.

Common technologies include passive infrared (PIR) sensors that detect thermal differences; ultrasonic and microwave radar sensors that transmit energy and listen for echoes; capacitive and inductive sensors that sense changes in electrical fields or magnetic fields caused by nearby motion; and vision-based approaches using cameras and image processing to track movement, sometimes aided by depth sensors or LiDAR.

Applications span security systems and intrusion detection; automatic lighting and occupancy-driven HVAC in smart buildings; consumer devices such as smartphones, wearables, gaming controllers, and home assistants; automotive driver monitoring and gesture control; and robotics and augmented reality where precise motion tracking is required.

Challenges include false positives and negatives, sensitivity to environmental conditions, occlusion, and limited range. Video- or camera-based sensing raises privacy and security concerns and may require consent and safeguards. Systems often use data processing at the edge or in the cloud, with calibration and maintenance needed to sustain accuracy and reliability.