Methods and apparatus for a capacitive sensor
AssigneeSemiconductor Components Industries, LLC
InventorsTakayasu OTAGAKI, Kensuke GOTO
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Abstract
Various embodiments of the present technology may provide methods and apparatus for a capacitive sensor configured to detect rain. The capacitive sensor may provide a reception electrode in communication with a drive electrode to form an electric field and a ground electrode surrounding the reception and drive electrodes. The ground electrode may couple the rain to a ground potential resulting in a decrease in the capacitance of the capacitive sensor.
Claims20
A capacitive sensor capable of detecting a liquid, comprising:
- a first electrode;
- a second electrode arranged planar with the first electrode, wherein the first and second electrode form a sensing capacitor;
- and
- a third electrode connected to a ground potential, wherein the third electrode:
- is planar with the first and second electrodes;
- and
- adjacent to an outer edge of the second electrode.
A method for detecting rain using a capacitive sensor, comprising:
- forming the capacitive sensor comprising:
- a first electrode;
- a second electrode arranged planar with the first electrode, wherein the first and second electrodes form a sensing capacitor;
- and
- a third electrode planar with the first and second electrodes and connected to a ground potential;
- coupling the rain to the ground potential via the third electrode;
- measuring a capacitance of the sensing capacitor;
- converting the capacitance to a digital value;
- comparing the digital value to a predetermined threshold value;
- and
- generating a logic signal according to the comparison;
- wherein:
- the logic signal is a first value if the digital value is less than the threshold value and indicates an absence of rain;
- and
- the logic signal is a second value if the digital value is greater than or equal to the threshold value and indicates a presence of rain.
A system for detecting rain on a surface, comprising:
- a capacitive sensor affixed to the surface and comprising:
- a first electrode;
- a second electrode arranged planar with the first electrode, wherein the first and second electrodes form a sensing capacitor;
- and
- a third electrode connected to a ground potential, wherein the third electrode is planar with the first and second electrodes and surrounds an outer perimeter of the second electrode;
- a sensing circuit connected to the capacitive sensor and configured to:
- measure a capacitance of the sensing capacitor;
- convert the capacitance to a digital value;
- compare the digital value to a threshold value;
- generate a logic signal according to the comparison;
- wherein:
- the logic signal is a first value if the digital value is less than the threshold value and indicates an absence of rain;
- and
- the logic signal is a second value if the digital value is greater than or equal to the threshold value and indicates a presence of rain;
- and
- a control circuit connected to an output terminal of the sensing circuit and configured to:
- receive the logic signal;
- and
- generate a control signal according to the logic signal, wherein the control signal controls an operation to remove the rain from the surface.
Dependencies are inferred from the claim text.