CAPACITIVE SENSING FOR WASHROOM FIXTURE

• US 20080109956A1
• Filed: 10/23/2007
• Published: 05/15/2008
• Est. Priority Date: 10/24/2006
• Status: Active Grant

• Current Assignee: Bradley Fixtures Corporation (Bradley Corporation)
• Original Assignee: Bradley Fixtures Corporation (Bradley Corporation)
• Inventors: Reckamp, Steven R., Guzzardo, Nick B., Kogler, Nathaniel J., Kreitzer, Kenneth A., Bayley, Graeme S.
• Granted Patent: US 8,381,329 B2
• Time in Patent Office: Days
• US Class Current: 4/623
• CPC Class Codes: E03C 1/057 touchless, i.e. using sensors

Abstract

A capacitive sensing system and method for a hand washing lavatory system is disclosed. The lavatory system comprises a receptacle defining a hand washing area, a fixture configured to deliver water to the receptacle, and a capacitive sensing system configured to detect the presence of a user and actuate the fixture. The capacitive sensing system comprises a first sense electrode coupled to the receptacle and configured to measure a first capacitive value, a second sense electrode coupled to the receptacle spaced apart from the first sense electrode and configured to measure a second capacitive value, and a circuit configured to control operation of the fixture in response to a change in the first capacitive value relative to the second capacitive value.

Claims

1. A hand-washing lavatory system comprising:

a receptacle defining a hand washing area;

a fixture configured to deliver water to the hand washing area;

a first sense electrode coupled to the receptacle and configured to measure a first capacitive value;

a second sense electrode coupled to the receptacle spaced apart from the first sense electrode and configured to measure a second capacitive value; and

a circuit configured to control operation of the fixture in response to a change in the first capacitive value relative to the second capacitive value.

2. The hand-washing lavatory system of claim 1 wherein the circuit comprises a sensing control and detection circuit configured to control the sensing and detection operation and provide an output signal that actuates the fixture.

3. The hand-washing lavatory system of claim 2 further comprising a power management and valve actuation circuit configured to manage the power supply and to actuate a valve between an open position and a closed position.

4. The hand-washing lavatory system of claim 3 further comprising photovoltaic cells configured to provide at least a portion of the power used to operate the circuits and valve.

5. The hand-washing lavatory system of claim 1 wherein the first sensor electrode is located below the wash area.

6. The hand-washing lavatory system of claim 5 wherein the second sensor electrode is located below the wash area.

7. The hand-washing lavatory system of claim 1 wherein the first sensor electrode is U-shaped.

8. The hand-washing lavatory system of claim 1 wherein the first sensor electrode is L-shaped and the second sensor electrode is located at least partially within the L-shape.

9. The hand-washing lavatory system of claims 7 wherein the second sensor electrode is located at least partially within the U-shape.

10. The hand-washing lavatory system of claim 1 wherein the first sensor electrode is located above the wash area and the second electrode is located below the wash area.

11. The hand-washing lavatory system of claim 1 wherein the first sensor electrode and the second sensor electrode are both located above the wash area.

12. The hand-washing lavatory system of claim 1 wherein at least one of the first sensor electrode and the second sensor electrode are integrated with at least one of the fixture, a drain, or combinations thereof.

13. The hand-washing lavatory system of claim 1 wherein the first sensor electrode and the second sensor electrode are at least partially encapsulated with the receptacle.

14. The hand-washing lavatory system of claim 1 wherein the fixture is a sprayhead.

15. The hand-washing lavatory system of claim 1 wherein the fixture is a faucet assembly

16. A hand-washing lavatory station comprising:

a deck having one or more receptacles providing one or more hand washing stations, and a sink line defining the top of the one or more receptacles;

at least one fixture located at least partially above the sink line and configured to deliver water to one or more of the hand washing areas;

a first sense electrode integrated with the deck and located below the sink line, the first electrode configured to measure a first capacitive value in the one or more hand washing area;

a second sense electrode integrated with the deck and located adjacent to the first electrode and below the sink line, the second electrode configured to measure a second capacitive value in the one or more hand washing area;

a valve movable between an open position wherein water is permitted to flow through the fixture and a closed position wherein water is prevented from flowing through the fixture;

a circuit coupled to the first electrode, the second electrode, and the valve, and configured to move the valve between the open position and the closed position in response to a change in the first capacitive value relative to the second capacitive value.

17. The hand-washing lavatory system of claim 16 wherein the receptacle is made from a non-conductive material.

18. The hand-washing lavatory system of claim 17 wherein the first sense electrode at least partially surrounds the second sense electrode.

19. The hand-washing lavatory system of claim 18 wherein the first sense electrode and the second sense electrode are integrally formed as part of a circuit board containing the circuit.

20. The hand-washing lavatory system of claim 19 wherein the first sense electrode is a first conductive area on the circuit board and the second sense electrode is a second conductive area on the circuit board spaced apart from the conductive area of the first sense electrode.

21. In a hand washing lavatory station comprising a deck, a first sense electrode, and a second sense electrode, the deck includes one or more hand-washing receptacles and a sink line defining the top of the one or more receptacles, the first sense electrode is integrated with the deck and located below the sink line and is configured to measure a first capacitive value in the one or more hand washing area, the second sense electrode is integrated with the deck and located adjacent to the first electrode and below the sink line and is configured to measure a second capacitive value in the one or more hand washing area, a method of operating the hand washing lavatory station comprising:

operating within a non-activated loop wherein the fixture is waiting to be used;

detecting a first capacitive value with a first sense electrode and a second capacitive value with a second sense electrode;

calculating a difference between the first capacitive value and the second capacitive value over a predetermined time period;

returning to the non-activated loop if an activation event has not occurred;

operating within an activated loop and activating a fixture for a hand washing operation if an activation event has occurred;

detecting a third capacitive value with the first sense electrode and a fourth capacitive value with the second sense electrode;

calculating a difference between the third capacitive value and the fourth capacitive value over a predetermined time period;

resetting the run time if a reactivation activation event has occurred the system;

decrementing the run time if the reactivation event has not occurred;

deactivating the fixture after expiration of the run time and returning to the delay period to check for further activation of the system.

22. The method of claim 21 further comprising the step of checking to determine whether water level in any of the receptacles is beyond a threshold value, if the water level is too high the system returns to delay period, if the water level is below the threshold, the system moves to the activated loop.

23. The method of claim 22 further comprising the step of checking for stored calibration constants, if no calibration constants exist the system calibrates and stores values followed by a delay period, if any calibration constants do exist the system proceeds to delay period intended to minimize power consumption and allow the lavatory system to operate and/or react to inputs or outputs.