A Novel Seat Occupancy Detection System based on Capacitive Sensing

This paper presents a simple and efficient seat occupancy detection scheme based on a capacitive sensing principle. Parameters such as presence, position and type of seat occupant are essential for successful air bag control in vehicles. In the absence of such information, on an accident, the air bag may be inflated to a vacant seat leading to its wastage and hence the associated repair and reinstallation. Also, if deployed, it can cause fatal injuries to infants in rear-facing infant seats. The proposed capacitive sensor system detects presence of an occupant and provides information about the occupant position. The developed system takes 200 mu s to complete a full set of measurements hence promises dynamic operation of the air bag system. The presented method employs a carrier frequency method and lock-in-amplifier technique to measure the capacitances. Thus, the influence of external electromagnetic fields on the final result is minimal.