Contactless capacitive obstacle detection system for automotive applications

A contactless obstacle detection system has been developed for automatic windows and doors to avoid painfully squeezing or injuries. The system takes advantage of the rubber profile of the opening. High reliability is achieved by complex analogue and digital signal processing. Moving average filters account for slow changing influences like temperature drift or material aging. Capacitance measurement at multiple frequencies allows the detection and distinction of rain and splash water to a real obstacle. The contactless obstacle detection system can be used in many applications. Further work is dedicated to implement additional versions of the measurement circuit for higher resolution down to a few Atofarads.