Proximity detection
First Claim
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1. A proximity sensor comprising:
- a sensing element having a capacitance to ground that is variable as a function of a proximity of an object to the sensing element;
an oscillator connected to the sensing element, wherein the oscillator includes a capacitor; and
control circuitry connected to the oscillator, the control circuitry configured to;
supply an excitation to the oscillator and a charge to the sensing element;
measure a resonant frequency of the oscillator, wherein the capacitance of the sensing element is in parallel with the capacitor of the oscillator such that changes to the capacitance of the sensing element change a capacitance of the oscillator, changing the resonant frequency of the oscillator; and
provide a signal indicative of the proximity of the object to the sensing element.
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Abstract
In certain embodiments, a proximity sensor includes a sensing element, an oscillator connected to the sensing element, and control circuitry connected to the oscillator. The sensing element has a capacitance to ground that is variable as a function of the proximity of an object to the sensing element. The oscillator includes a capacitor. The control circuitry is configured to supply an excitation to the oscillator and a charge to the sensing element, and to measure the resonant frequency of the oscillator. The control circuitry provides a signal indicative of the proximity of the object to the sensing element.
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Citations
20 Claims
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1. A proximity sensor comprising:
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a sensing element having a capacitance to ground that is variable as a function of a proximity of an object to the sensing element; an oscillator connected to the sensing element, wherein the oscillator includes a capacitor; and control circuitry connected to the oscillator, the control circuitry configured to; supply an excitation to the oscillator and a charge to the sensing element; measure a resonant frequency of the oscillator, wherein the capacitance of the sensing element is in parallel with the capacitor of the oscillator such that changes to the capacitance of the sensing element change a capacitance of the oscillator, changing the resonant frequency of the oscillator; and provide a signal indicative of the proximity of the object to the sensing element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A proximity sensor controller, comprising:
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control circuitry adapted to be connected to an oscillator and a sensing element, the sensing element having a capacitance to ground that is variable as a function of proximity of an object to the sensing element, the control circuitry configured to execute instructions that cause the control circuitry to perform operations to measure a change in a resonant frequency of the oscillator, the operations comprising; supplying an excitation signal to the oscillator, the oscillator comprising a capacitor; supplying a charge to the sensing element; measuring the change in the resonant frequency of the oscillator, wherein the capacitance of the sensing element is in parallel with the capacitor of the oscillator such that changes to the capacitance of the sensing element change a capacitance of the oscillator, changing the resonant frequency of the oscillator; and providing a signal indicative of the proximity of the object to the sensing element. - View Dependent Claims (12, 13, 14, 15)
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16. An article of manufacture comprising:
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a non-transitory machine readable storage medium; and executable program instructions embodied in the non-transitory machine readable storage medium that when executed by a processor of a programmable computing device configures the programmable computing device to control a proximity sensor having control circuitry connected to an oscillator and a sensing element, wherein the sensing element has a capacitance to ground that is variable as a function of the proximity of a person or object to the sensing element, to perform operations to measure the change in the resonant frequency of the oscillator, including operations to; supply an excitation signal to the oscillator; supply a charge to the sensing element; measure the change in the resonant frequency of the oscillator, wherein the capacitance of the sensing element is in parallel with the capacitor of the oscillator such that changes to the capacitance of the sensing element change a capacitance of the oscillator, changing the resonant frequency of the oscillator; and provide a signal indicative of the proximity of the object to the sensing element. - View Dependent Claims (17, 18, 19, 20)
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Specification