Method for alerting physical approach
First Claim
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1. 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.
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Abstract
A method and apparatus is described to detect the physical approach. The method is useful for passively detecting the presence of people, pets, or robots in proximity to a sensor. It is portable, and functions while being carried or placed inside objects.
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Citations
17 Claims
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1. A device for detecting presence or motion of interest in an area, comprising:
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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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A device for detecting presence or motion of interest in an area, comprising:
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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 second E-field sensing antenna, a second high input impedance amplifier coupled to the second E-field sensing antenna and producing output signals related to the E-field sensed, a differential amplifier producing an output signal proportional to the difference of voltages between the output of the second E-field sensing antenna and the output of the E-field sensing antenna, and a detection circuit for detecting sensed AC signals of interest and sensed substantially DC signals of interest from the differential amplifier and providing an output signal indicative thereof, said output signal indicating presence or motion of interest in the area. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A device for detecting presence or motion of interest in an area, comprising:
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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 detection circuit for detecting sensed AC signals of interest and sensed substantially DC signals of interest and providing an output signal indicative thereof; means to provide control signals in response to the signals of interest; and a background source of AC voltage adapted for connection to a user so that the user'"'"'s body conducts the background AC voltage; whereby, as the user'"'"'s body moves, signals of interest are produced which produce control signals in response to the movement of the user'"'"'s body.
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16. A device for detecting presence or motion of interest in an area, comprising:
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an E-field sensing antenna for sensing AC 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 of the E-field sensed; 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; and a detection circuit for detecting sensed AC signals of interest and providing an output signal indicative thereof, said output signal indicating presence or motion of interest in the area.
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17. A device for detecting presence or motion of interest in an area, comprising:
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an E-field sensing antenna for sensing 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 substantially DC components of the E-field sensed; 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 substantially DC signals of interest and providing an output signal indicative thereof, said output signal indicating presence or motion of interest in the area.
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Specification