A Transmitter—Receiver System for Long-Range Capacitive Sensing Applications

Abstract

Abstract-Human-occupancy detection and localization are important in a variety of smart-building applications including building security, assisted-living monitors, and energy-efficient HVAC and lighting. Current implementation of such systems are limited by motion-sensor technologies, e.g. passive infrared (PIR) and ultrasonic sensors, which substitute as occupancy detectors but ultimately suffer from an inability to detect stationary objects. Capacitive sensing can detect stationary objects, but the technology has almost exclusively been developed for shortrange human detection and localization, e.g. touch-screen human interfacing of smart-devices. This paper presents a transmitterreceiver platform for research and development of capacitive sensing for long-range human-occupancy detection and localization. During testing, the system revealed a detection range of 3.5 meters, a typical room dimension in homes. Further, tests of a multi-transmitter, single-receiver system in a 3.2 m x 3.2 m space showed the system's potential for occupant-localization. Ultimately, this system represents an alternative to PIR and ultrasonic motion sensors, and has the potential to increase smart-building system implementation.

CapLoc: Capacitive Sensing Floor for Device-Free Localization and Fall Detection

“…The detected change in the signal amplitude caused by a person between the electrode and the floor tile helps infer the location. Capacitive sensing is also utilized in research [36,37] where instead of using the floorbased solution, electrodes are set up on the walls.…”