Temperature compensated windshield moisture detector
First Claim
1. A moisture detection system comprising:
- an electrical conductor disposed on a surface of a substrate and having a resonant frequency that varies as a function of an amount of moisture present adjacent the electrical conductor;
an oscillator which outputs an oscillator signal at a predetermined amplitude and a predetermined frequency;
a resonator circuit coupled to the electrical conductor and responsive to the oscillator signal for outputting a resonator signal having an amplitude related to the resonant frequency of the electrical conductor;
a filter circuit responsive to the resonator signal for outputting a rectified and filtered signal;
an analog-to-digital converter responsive to the rectified and filtered signal for outputting a digital signal related to the rectified and filtered signal;
a sensor having a property that varies as a function of a temperature at or adjacent the electrical conductor; and
a controller responsive to the digital signal and the property of the sensor for causing another system to operate as a function thereof.
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Accused Products
Abstract
A moisture detection system includes an electrical conductor disposed on a surface of a substrate, an oscillator for outputting an oscillator signal at a predetermined amplitude and a predetermined frequency, and a resonator circuit coupled to the electrical conductor and responsive to the oscillator signal for outputting a resonator signal having an amplitude related to a resonant frequency of the electrical conductor. A filter circuit responsive to the resonator signal can output a rectified and filtered signal, and an analog-to-digital converter responsive to the rectified and filtered signal can output a digital signal related to the rectified and filtered signal. A sensor can be provided having a property that varies as a function of a temperature at or adjacent the electrical conductor. A controller can be responsive to the digital signal and the property of the sensor for causing another system to operate as a function thereof.
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Citations
24 Claims
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1. A moisture detection system comprising:
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an electrical conductor disposed on a surface of a substrate and having a resonant frequency that varies as a function of an amount of moisture present adjacent the electrical conductor; an oscillator which outputs an oscillator signal at a predetermined amplitude and a predetermined frequency; a resonator circuit coupled to the electrical conductor and responsive to the oscillator signal for outputting a resonator signal having an amplitude related to the resonant frequency of the electrical conductor; a filter circuit responsive to the resonator signal for outputting a rectified and filtered signal; an analog-to-digital converter responsive to the rectified and filtered signal for outputting a digital signal related to the rectified and filtered signal; a sensor having a property that varies as a function of a temperature at or adjacent the electrical conductor; and a controller responsive to the digital signal and the property of the sensor for causing another system to operate as a function thereof. - View Dependent Claims (2, 3, 4)
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5. A moisture detector system comprising:
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means disposed on a substrate for conducting electrical current, the conducting means having a resonant frequency that changes as a function of moisture adjacent the conducting means; an oscillator for outputting to the conducting means an oscillator signal having a predetermined frequency and a first amplitude; means responsive to the oscillator signal for outputting a resonator signal having a second amplitude related to the resonant frequency of the conducting means, wherein the second amplitude is different than the first amplitude; means having a property whose value varies as a function of a temperature at or adjacent the conducting means; and means responsive to the resonator signal and the value of the property for outputting a control signal having a value related to the second amplitude of the resonator signal. - View Dependent Claims (6, 7, 8, 9)
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10. A method of moisture detection comprising:
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(a) providing a substrate having an electrical conductor disposed thereon; (b) stimulating the electrical conductor with an oscillator signal in the absence of moisture adjacent the electrical conductor; (c) detecting a value of a temperature dependent property acquired from a location at or adjacent the electrical conductor on or about the time step (b) is performed; (d) determining a first amplitude of the electrical conductor to the stimulation in step (b) as a function of the value of the temperature dependent property detected in step (c); (e) stimulating the electrical conductor with the oscillator signal when moisture is present adjacent the electrical conductor; (f) detecting the value of the temperature dependent property on or about the time step (e) is performed; (g) determining a second amplitude of the electrical conductor to the stimulation in step (e) as a function of the value of the temperature dependent property detected in step (f), wherein the second amplitude is different than the first amplitude due to a change in resonant frequency of the electrical conductor in response to the presence of moisture adjacent the electrical conductor; and (h) determining a difference between the first amplitude and the second amplitude, wherein the difference is related to the amount of moisture present adjacent the electrical conductor. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A moisture detection system comprising:
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a substrate; an electrical conductor disposed on the substrate; means for stimulating the electrical conductor with an oscillator signal; means for determining a temperature at or adjacent the electrical conductor; and means responsive to the oscillator signal, the electrical conductor and the determined temperature for determining temperature corrected changes in a resonant frequency of the electrical conductor in response to changes in an amount of moisture disposed adjacent the electrical conductor. - View Dependent Claims (18)
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19. A method of moisture detection comprising:
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correcting a value of a signal generated in response to the presence of moisture on a substrate as a function of a temperature determined at or adjacent the substrate; and controlling a system as a function of the corrected signal.
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20. A method of moisture detection comprising:
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generating a signal having a value related to an amount of moisture on a substrate; combining the signal with a correction factor related to a temperature determined at or adjacent the substrate; and controlling a system as a function of the combination.
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21. A moisture detection system comprising:
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a substrate; a resistive conductor disposed on the substrate; a source of DC power; means for generating an AC oscillator signal; means for applying the DC power and the AC oscillator signal one at a time to the resistive conductor; and means responsive to the application of the oscillator signal to the resistive conductor for determining changes in a resonant frequency of the resistive conductor in response to changes in an amount of moisture disposed adjacent the resistive conductor. - View Dependent Claims (22)
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23. A method of moisture detection comprising:
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(a) connecting a resistive conductor to a source of DC power; (b) disconnecting the resistive conductor from the source of DC power; (c) connecting the resistive conductor to an AC signal source; (d) in response to the application of the AC signal source, determining a change in a resonant frequency of the resistive conductor related to a change in an amount of moisture adjacent the resistive conductor; and (e) removing moisture from adjacent the resistive conductor as a function of the change in the resonant frequency thereof. - View Dependent Claims (24)
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Specification