Capacitive touch sensor

• US 8,376,313 B2
• Filed: 03/24/2008
• Issued: 02/19/2013
• Est. Priority Date: 03/28/2007
• Status: Active Grant

• Current Assignee: Delta Faucet Company (Masco Corporation)
• Original Assignee: Masco Corporation Of Indiana (Masco Corporation)
• Inventors: Pandini, Fabio, Burke, David M
• Primary Examiner(s): Fristoe, Jr., John
• Assistant Examiner(s): JELLETT, MATTHEW WILLIAM
• Application Number:
  US12/523,013
• Publication Number:
  US 20100044604A1
• Time in Patent Office: 1,793 Days
• Field of Search: 25112903-12906, 462/3, 327/517
• US Class Current: 251/129.04
• CPC Class Codes: E03C 1/057 touchless, i.e. using sensors
• CPC Class Codes: Y10T 137/9464 Faucets and spouts

Abstract

A fluid delivery apparatus comprises a spout, a fluid supply conduit supported by the spout, a valve assembly to supply fluid through the fluid supply conduit, and a capacitive touch sensor. The capacitive touch sensor is coupled to a controller. The controller is also coupled to the valve assembly. The controller is configured to detect a user touching the sensor and to control flow of fluid through the fluid supply conduit.

Claims

1. A fluid delivery apparatus comprising:

a spout;

a fluid supply conduit supported by the spout;

a valve assembly to supply fluid through the fluid supply conduit;

a capacitive touch sensor including an electrode, a pulse generator, a DC filter coupled to an output of the pulse generator and the electrode and configured to filter a DC component of the combined signals from the electrode and the pulse generator to provide an AC output signal, a rectifier having an input coupled to an output of the DC filter to provide a DC output signal; and

a controller coupled to an output of the rectifier, the controller also being coupled to the valve assembly, the controller being configured to detect a user touching the electrode based on the DC output signal from the rectifier and configured to control flow of fluid through the fluid supply conduit.

2. The apparatus of claim 1, wherein the pulse generator is one of a square wave generator, a sine wave generator, and a triangle wave generator.

3. The apparatus of claim 1, wherein the pulse generator generates an output signal having a frequency of about 100 kHz.

4. The apparatus of claim 1, wherein the pulse generator generates an output signal having a frequency greater than 100 kHz.

5. The apparatus of claim 1, wherein the DC filter includes a series of resistors and capacitors configured to filter a DC component of an output signal from the pulse generator.

6. The apparatus of claim 1, wherein the DC filter reacts to changes in capacitive due to the user touching the electrode and ignores an effect of resistance impedance due to water flowing through the fluid supply conduit.

7. The apparatus of claim 1, wherein the rectifier includes an operational amplifier specified to swing from rail-to-rail.

8. The apparatus of claim 1, further comprising means for coupling the capacitive touch sensor to earth ground.

9. The apparatus of claim 1, wherein the electrode is coupled to the spout.

10. The apparatus of claim 9, wherein the spout is formed from a conductive material.

11. The apparatus of claim 1, wherein the controller detects a change in a dielectric constant adjacent the electrode.

12. The apparatus of claim 1, wherein the controller controls the valve assembly to adjust fluid flow through the fluid supply conduit based on capacitance changes detected by the capacitive touch sensor.

13. The apparatus of claim 1, wherein the electrode is embedded in a non-conductive material forming the spout.

14. The apparatus of claim 1, wherein the controller is configured to actuate the valve assembly automatically and supply fluid through the fluid supply conduit in response to detecting a user touching the electrode.

15. The apparatus of claim 1, wherein the fluid supply conduit is separate from the spout.

16. The apparatus of claim 1, wherein the electrode is coupled to an outer surface of the spout.

17. The apparatus of claim 1, further comprising a proximity sensor located adjacent the spout, the proximity sensor being coupled to the controller to provide a hands free supply of fluid through the fluid supply conduit in response to detecting a user'"'"'s presence with the proximity sensor, and the controller switching back and forth between a manual mode and a hands free mode in response to the capacitive touch sensor detecting the user touching the electrode.

18. The apparatus of claim 1, wherein the electrode is coupled to a handle for controlling fluid flow.

19. The apparatus of claim 1, further comprising a handle for manually controlling the valve assembly to provide fluid flow through the fluid supply conduit, the controller switching between back and forth a manual mode and an automatic mode in response to the capacitive touch sensor detecting the user touching the electrode.

20. The apparatus of claim 1, further comprising a filter stage having an input coupled to the output of the rectifier and an output coupled to the controller.

21. The apparatus of claim 20, further comprising an analog-to-digital converter having an input coupled to the output of the filter stage and an output coupled to the controller.

22. The apparatus of claim 21, further comprising an amplifier coupled between the output of the filter stage and the input of the analog-to-digital converter.

23. The apparatus of claim 20, wherein the filter stage comprises a low pass filter which provides a DC voltage supply to the analog-to-digital converter.

24. The apparatus of claim 1, wherein the rectifier is a full wave rectifier.

25. A capacitive touch sensor comprising:

an electrode;

a pulse generator;

a DC filter coupled to an output of the pulse generator and to the electrode, the DC filter being configured to filter a DC component of a combined signal from the electrode and the pulse generator to provide an AC output signal;

a rectifier having an input coupled to an output of the DC filter to rectify the AC output signal and provide a DC output signal; and

a control circuit coupled to an output of the rectifier, the control circuit being configured to detect a user touching the electrode based on changes in the DC output signal.

26. The sensor of claim 25, wherein the control circuit detects a user touching the electrode based on changes in a DC voltage level of an output signal from the rectifier.

27. The sensor of claim 25, wherein the pulse generator is one of a square wave generator, a sine wave generator, and a triangle wave generator.

28. The sensor of claim 25, wherein the pulse generator generates an output signal having a frequency of about 100 kHz.

29. The sensor of claim 25, wherein the pulse generator generates an output signal having a frequency greater than 100 kHz.

30. The sensor of claim 25, wherein the DC filter includes a series of resistors and capacitors configured to filter the DC component of the combined signal from the pulse generator and the electrode.

31. The sensor of claim 25, wherein the DC filter reacts to changes in capacitive due to the user touching the electrode and ignores an effect of resistance impedance.

32. The sensor of claim 25, wherein the rectifier includes an operational amplifier specified to swing from rail-to-rail.

33. The sensor of claim 25, further comprising means for coupling the capacitive touch sensor to earth ground.

34. The sensor of claim 25, wherein the controller detects a change in a dielectric constant adjacent the electrode.

35. The sensor of claim 25, further comprising a filter stage having an input coupled to the output of the rectifier and an output coupled to the controller.

36. The sensor of claim 35, further comprising an analog-to-digital converter having an input coupled to the output of the filter stage and an output coupled to the controller.

37. The sensor of claim 36, further comprising an amplifier coupled between the output of the filter/sample stage and the input of the analog-to-digital converter.

38. The sensor of claim 35, wherein the filter stage comprises a low pass filter which provides a DC voltage supply to the analog-to-digital converter.

39. The sensor of claim 25, wherein the rectifier is a full wave rectifier.