Temperature compensated windshield moisture detector

A moisture detector system comprising:

• 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.

A method of moisture detection comprising:

• (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.

A moisture detection system comprising:

• 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.

A method of moisture detection comprising:

• 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.

A moisture detection system comprising:

• 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.

A method of moisture detection comprising:

• (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.