Wireless swimming pool water level system
First Claim
1. A capacitive sensor for determining liquid level, comprising:
- a surface adjacent which the liquid is present, and on which the fluid defines a level;
a single reference electrode at a lower part of the surface;
a first sensor electrode arranged at least in part above the reference electrode at the surface; and
a second sensor electrode arranged at least in part above the first sensor electrode and at the surface;
wherein each of the first and second sensor electrode has a greater area at the surface than does the reference electrode; and
wherein the surface is defined by one or more passages through the sensor and the electrodes are each concentric to one of the passages.
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Accused Products
Abstract
A wireless (e.g., radio) system and method for automatic water level maintenance of, e.g., a swimming pool utilizing capacitive liquid level sensing. A reference electrode allows water level sensing independent of the water chemistry or temperature. Capacitive electrodes having areas larger than the reference electrode sense various liquid levels when the liquid covers an area of any sensing electrode equal to the area of the reference electrode. Averaging is incorporated to filter out effects of wind or other disturbances. Upon sensing a given condition, the transmitter transmits a sensed condition to a remote receiver for control of valves and pumps for changing the water level in the pool. The receiver includes safety timers for filling and emptying to protect against equipment failure or communications faults. User selectable identification allows identical such radio systems to operate within proximity to each other. Power saving features are used to extend battery life.
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Citations
24 Claims
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1. A capacitive sensor for determining liquid level, comprising:
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a surface adjacent which the liquid is present, and on which the fluid defines a level; a single reference electrode at a lower part of the surface; a first sensor electrode arranged at least in part above the reference electrode at the surface; and a second sensor electrode arranged at least in part above the first sensor electrode and at the surface; wherein each of the first and second sensor electrode has a greater area at the surface than does the reference electrode; and wherein the surface is defined by one or more passages through the sensor and the electrodes are each concentric to one of the passages. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A capacitive liquid level sensor comprising:
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a reference electrode defining a surface area and positioned over a surface; a first electrode defining a surface area and positioned over the surface, wherein the surface area of the first electrode is greater than the surface area of the reference electrode, and wherein a geometric center of the surface area of the first electrode is positioned above a geometric center of the surface area of the reference electrode; a second electrode defining a surface area and positioned over the surface, wherein the surface area of the second electrode is greater than the surface area of the reference electrode, and wherein a geometric center of the surface area of the second electrode is positioned above the geometric center of the surface area of the first electrode; and measuring logic to measure a representation of a capacitance at the first electrode relative to a capacitance at the reference electrode and to measure a representation of a capacitance at the second electrode relative to a capacitance at the reference electrode. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method of controlling a liquid level in a reservoir, the method comprising:
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measuring a representation of a capacitance at a first electrode relative to a capacitance at a reference electrode; measuring a representation of a capacitance at a second electrode relative to a capacitance at the reference electrode; determining the liquid level has decreases to a first predetermined level based on the representation of the capacitance at the first electrode; sending a signal to start filling the reservoir in response to determining the liquid level has decreases to the first predetermined level; determining the liquid level has increases from the first predetermined level to a second predetermined level based on the representation of the capacitance at the second electrode; and sending a signal to stop filling the reservoir in response to determining the liquid level has increases from the first predetermined level to the second predetermined level. - View Dependent Claims (22, 23, 24)
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Specification