Patent ID: 6774789
Filing Date: 2004-08-10
Classification: B60R,G07C

Abstract:
A human body detector comprising:a capacitance-type sensor that a human body contacts or approaches, the capacitance-type sensor including a sensor resonance circuit and a wave detector circuit; detection means for receiving an output of the capacitance-type sensor, and distinguishing between the human body from a raindrop and detecting only the human body based on a change in the output within a predetermined time, the detection means including a band-pass filter, the band-pass filter including a differentiator, a high-pass filter and a comparator; and wherein the sensor resonance circuit has a sensor electrode supplied with a constant frequency voltage and outputs a resonance voltage integrated the constant frequency voltage with respect to a capacitance of an object that contacts to the sensor electrode, the wave detector circuit outputs a wave detection voltage obtained through wave detection and conversion of the resonance voltage, and the differentiator differentiates the wave detection voltage with respect to time to acquire the changing rate.