Patent ID: 8009045

Claim:
A device for detecting presence or motion of interest in an area, comprising: an E-field sensing antenna for sensing AC and substantially DC components of an E-field within the area; a high input impedance amplifier having an input coupled to the E-field sensing antenna and producing output signals related to the sensed AC components and sensed substantially DC components of the E-field sensed; a low pass filter for separating the output signals related to the sensed substantially DC components of the E-field from the output signals related to the sensed AC components of the E-field; a high pass filter for separating the output signals related to the sensed AC components of the E-field from the output signals related to the sensed substantially DC components of the E-field; an automatic gain control circuit for controlling the amplification of the output signals related to the sensed AC components to compensate for changes in background AC signal amplitudes to emphasize sensed AC signals of interest; an automatic background DC offset correction circuit to compensate for changes in background substantially DC signal amplitudes to emphasize sensed substantially DC signals of interest; and a detection circuit for detecting sensed AC signals of interest and sensed substantially DC signals of interest and providing an output signal indicative thereof, said output signal indicating presence or motion of interest in the area.