Capacitive coupling arrangement for a faucet

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-1CAPACIT1VE COUPLING ARRANGEMENT FOR A FAUCET

BACKGROUND AND SUMMARY OF THE INVENTION

[0001] The present invention relates to improvements in capacitive sensors for activation of faucets. More particularly, the present invention relates to the placement of a capacitive touch sensors in or ad jacent to faucet spouts and faucet handles to sense touches by a user of the faucet and then control the faucet based on output signals from the capacitive sensor.

[0002] An ii lustrated embodiment, a faucet includes a touch sensor in a spout of the faucet, and another touch sensor in a manual valve handle. The touch sensor in the spout permits a user to turn water flow on and off merely by tapping the spout. In the illustrated embodiment, the faucet distinguishes between a tap on the spout to turn the water flow on or off, and a longer grasping or grab of the spout, for example, to swing it from one basin of a sink to another. The faucet therefore provides an easy and convenient way to turn the water off and on without having to adjust the water flow rate and temperature.

[0003] The touch sensor in the handle can also be used for a tap control, which distinguishes between grasping or grab of the handle to adjust the water flow rate or temperature, and merely tapping the handle to toggle water flow off or on. The touch sensor in the handle provides an additional source of input data for the faucet which permits the faucet to more accurately determine the intent of the user, thereby providing greater water savings while being intuitive and easy to use.

[0004] According to an illustrated embodiment of the present disclosure, a faucet comprises a spout, a passageway that conducts fluid flow through the spout, a electrically operable valve located within the passageway, a manual valve located within the passageway in series with the electrically operable valve, and a manual handle that controls the manual valve. The faucet also comprises a first touch sensor on the manual valve handle, a second touch sensor on the spout, a capacitive sensor directly coupled to one of the first and second touch sensors and capacitively coupled to the other of the first and second touch sensors, and a controller coupled to the capacitive sensor. The capacitive sensor provides an output signal. The controller is configured to monitor the output signal from the capacitive sensor and to distinguish between a user tapping one of the spout and the manual valve handle, a user grabbing the spout, and a user grabbing the manual valve handle. The controller is also coupled to the electrically operable valve to control the electrically operable valve is response to the output signal from the capacitive sensor.

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-2[0005] According to another illustrated embodiment of the present disclosure, a method is provided for controlling fluid flow in a faucet having a spout, a passageway that conducts fluid flow through the spout, a electrically operable valve located within the passageway, a manual valve located within the passageway in series with the electrically operable valve, and a manual handle that controls the manual valve. The method comprises providing a first touch sensor on the manual valve handle, providing a second touch sensor on the spout, providing a capacitive sensor, directly coupling one of the first and second touch sensors to the capacitive sensor, capacitively coupling the other of the first and second touch sensors to the same capacitive sensor, monitoring an output signal from the capacitive sensor to detect touches of both the first and second touch sensors by a user, and controlling the electrically operable valve is response to the monitoring step.

[0006] Additional features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the invention as presently perceived. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The detailed description of the drawings particularly refers to the accompanying figures in which:

[0008] Fig. I is a block diagram of a fluid delivery assembly including a capacitive sensor system;

[0009] Fig. 2 is an example of a dual-electrode, capacitively coupled sensing system with a single capacitive sensor:

[0010] Fig. 3 is a block diagram illustrating a spout of a fluid delivery assembly capacitively coupled to a faucet body hub by an insulator;

[0011] Fig. 4 illustrates a signal amplitude output in response to short taps and longer grabs on the first and second electrodes of Figs. 1 and 2;

[0012] Fig. 5 is a flow chart illustrating steps performed by a controller to distinguish between short taps and longer grabs on the first and second electrodes of a capacitive sensor system of Figs. 1 and 2; and

[0013] Fig. 6 is an operation state diagram illustrating control of fluid flow based on an output of the capacitive sensor.

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-3DETAILED DESCRIPTION OF THE DRAWINGS

[0014] For the purposes of promoting an understanding of the principles of the invention, reference will now be made to certain illustrated embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Such alterations and further modifications of the invention, and such further applications of the principles of the invention as described herein as would normally occur to one skilled in the art to which the invention pertains, are contemplated and desired to be protected.

[0015] Fig. I is a block diagram illustrating one embodiment of a sensing faucet system 10 of the present invention. The system 10 includes a spout 12 for delivering fluid such as water into a sink basin, for example, and at least one manual valve handle 14 for controlling the flow of water through the spout 12 in a manual mode. A hot water source 16 and cold water source 18 are illustratively coupled to a manual valve body assembly 20. In one illustrated embodiment, separate manual valve handles 14 are provided for the hot and cold water sources 16, 18. In another illustrated embodiment, such as for a kitchen application, a single manual valve handle 14 is used for both hot and cold water delivery. In such kitchen embodiment, the manual valve handle 14 and spout 12 are typically coupled to the basin through a single hole mount. An output of valve body assembly 20 is coupled to an actuator driven valve 22 which is controlled electronically by input signals from a controller 24. Valves 20 and 22 are illustratively located in a passageway that conducts fluid flow through the spout 12. In an illustrative embodiment, actuator driven valve 22 may be a magnetically latching pilotcontrolled solenoid valve.

(0016] In an alternative embodiment, the hot water source 16 and cold water source 18 may be connected directly to actuator driven valve 22 to provide a fully automatic faucet without any manual controls, in yet another embodiment, the controller 24 controls an electronic proportioning valve (not shown) to supply water for the spout 12 from hot and cold water sources 16, 18.

[0017] Because the actuator driven valve 22 is controlled electronically by controller 24, flow of water can be controlled using outputs from a capacitive sensor 30 as discussed herein. As shown in Fig. 1, when the actuator driven valve 22 is open, the faucet system may be operated in a manual control mode through operation of the handle(s) 14 and the manual valve member of valve body assembly 20. Conversely, when the manually controlled valve body assembly 20 is set to select a water temperature and flow rate, the actuator driven valve 22 can

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-4be touch controlled when a user's hands touch a sensor to toggle water flow on and off as discussed below.

|0018| A first touch sensor electrode 26 is electrically coupled to the manual valve handle(s) 14. Spout 12 illustratively has a second touch sensor electrode 28 capacitively coupled to the first electrode 26. The spout 12 is illustratively made from a conductive material to form the second touch sensor electrode 28. Alternatively, a separate electrode 28 may be coupled to the spout 12.

|0019] First electrode 2.6 is directly coupled to the capacitive sensor 30 of controller 24. In the embodiment of Fig. 1, a wire is used to connect the first electrode 26 to the capacitive sensor 30. It is understood that any conventional capacitive sensor 30 may be used in accordance with the present invention. See, for example, U.S. Patent No. 6,962,168. Since the spout 12 is often movable, it is not desirable to have a wire connection to the electrode 28 of spout 12. Therefore, the electrode 28 of spout 12 is capacitively coupled to the electrode 26 as discussed in more detail below, It is understood that in another embodiment, the second electrode 28 on the spout 12 may be directly coupled to the capacitive sensor 30 and the first electrode 26 on the handle 14 may be capacitively coupled to the first electrode 28.

[0020) Fig. 2 is an example of a dual electrode, capacitively coupled sensing arrangement using a single capacitive sensor 30. Although the embodiment of Fig. 2 is spcciHcally disclosed herein for use with a fluid delivery apparatus such as a faucet, it is understood that the sensing and control techniques used herein may have other applications.

)0021) Fig. 3 illustrates additional details of a single hole mount faucet 31. A faucet body hub 32 is electricaly coupled to the manual valve handle 14, for example, by metal-tometal contact between the handle 14 and the hub 32. Manual valve handle 14 is movably coupled to the faucet body hub 32 in a conventional manner to control water flow and temperature through valve 20. Since the manual valve handle 14 and the faucet body hub 32 are electrically connected, the first electrode 26 may be coupled to either the manual valve handle 14 or the hub 32, as desired.

)0022) The spout 12 is coupled to faucet body hub 32 by an insulator 34. In one embodiment, such as for a kitchen faucet, the spout 12 is rotatable relative to the faucet body hub 32. In other embodiments, the spout 12 may be fixed relative to the faucet body hub 32. Spout 12 may include a pull-out or pull-down spray head which is electrically isolated from the spout 12.

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-5[0023] As discussed above, the manual valve handle 14 is electrically connected to the faucet body huh 32. The spout 12 is capacitively coupled to the body hub by insulator 34. When the manual valve handle 14 is touched by a user's hand, the capacitance to earth ground is directly coupled. The capacitive sensor 30 of controller 24 therefore detects a larger capacitance difference when the handle 14 is touched by a user compared to when the spout 12 is touched.

This results in a larger amplitude output signal when the manual valve handle 14 is touched by a user's hand compared to when the spout 12 is touched. By comparing the amplitude of the output signal to predetermined threshold values, the controller 24 can detect where the faucet is touched and how long the faucet is touched to enable the controller 24 to make water activation decisions as discussed below.

[0024] The following is a description of algorithms used to process touch conditions of two electrodes 26. 28 which are capacitively coupled to one another using a single capacitive sensor 30 which detects changes in electrical capacitance. The interpretation of how and when the electrodes 26, 28 are touched is used to determine when to actuate an electronic valve 22.

[0025] It should be appreciated that the method and apparatus detailed herein may be used in connection with the faucet disclosed in PCT International Patent Application Publication No. WO 2008/088534 entitled MULTI-MODE HANDS FREE AUTOMATIC FAUCET, filed December 11, 2007, and U.S. Patent Application Serial No. 11/641,574, filed December 29, 2006, and published as U.S. Publication No. 2007/0157978.

[0026] A first embodiment of a detection algorithm for distinguishing between short taps and longer grabs of the spout 12 or handle 14. for example, will be described first. The following definitions are used in the first example of the detection algorithm. A tap is a touch of short duration designed to turn the water or fluid on or off. A grab has a longer duration such as when a user grasps the spout 12 to move the spout from one area of the sink basin to such as when a user grasps the spout 12 to move the spout from one area of the sink basin to another or when the user grasps the manual valve handle 14 to adjust the flow rate or temperature of the fluid. The following definitions apply to the first embodiment. Taps and grabs are determined differently in the second embodiment discussed below.

• Slew Rate: The maximum rate of change of an output signal, expressed in units/second. (Example: counts/second, volts/second, LSbs/second) • Direct Coupling: the connection of an electrode that is resistively coupled, or connected, to the input of a sensor.

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DFC-P0086-WO • Capacitive Coupling: an electrode’s connection to the input of a sensor which is capacitive in nature due to a physical separation by some material with a defined dielectric constant. There is no resistive element in the connection in this type of configuration.

• Tap: an event which occurs when a sensor’s output signal crosses above the absolute value of a pre-defined threshold for some period, t_R, and the following condition is met: Ttap min < U < Γτλρ μλχ· • Grab: Λ n event which occurs any time a sensor’s output signal crosses above the absolute value of a pre-defined threshold for at least Τγλρ_μαχ· • Touch: An event which is defined as any time a sensor’s output signal crosses above the absolute value of a pre-defined threshold for at least Ttap min- * Release: An event which is defined as any time a sensor's output signal crosses below the absolute value of a pre-defined threshold.

• Ttap wn- A defi ned, minimum, amount of time which a sensor’s output signal must cross above the absolute value of a pre-defined threshold to qualify as a tap condition.

• ΤτΛΡΜΑχ· A defined, maximum, amount of time which a sensor’s output signal must crosses above the absolute value of a pre-defined threshold to qualify as a tap condition. The signa! must have dropped below the threshold prior to this time to still qualify as a tap condition. If the signal is still above the threshold beyond this period of time, a grab condition has occurred.

[0027] Fig. 4 illustrates a typical output response signal of a dual electrode 26, 28, capacitively coupled sensing arrangement using a single capacitive sensor 30 as discussed above. The distinction between human touches on each electrode 26, 28 can be seen in Fig. 4. Possible algorithm threshold settings are shown on the graph of Fig. 4. For example, Fig. 4 illustrates a lower threshold amplitude at line 80, a middle threshold amplitude at line 82, and an upper threshold amplitude illustrated at line 84.

10028] Due to the slew rate of a chosen sensor connected to a particular electrode, it will take some minimum amount of time for the output signal to reach its maximum amplitude and achieve some steady state level This is shown in Fig. 4 in which the directly coupled first electrode 26 is tapped at location 90. and the maximum output level of the sensor is less than the maximum output level achievable if the first electrode 26 is grabbed for a minimum amount of

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-7time to allow a steady state level to be reached as illustrated at location 92. The slew rate for a directly coupled electrode 26 and a capacitively coupled electrode 28 may differ. The maximum achievable amplitude of a capacitively coupled electrode 28 is less than the maximum achievable amplitude of a directly coupled electrode 26. For example, location 86 of Fig. 4 illustrates the amplitude of the signal when capacitively coupled electrode 28 is tapped and location 88 illustrates the maximum achievable amplitude of the capacitively coupled electrode 28 when the electrode 28 is grabbed to allow a steady state level to be reached. The maximum steady state level achievable by a given sensor in a given system may vary depending on the following conditions:

1. What, or who, is touching the sensor,

2. The particular type of capacitive sensing technology employed by the system,

3. The amount of caoacitance between the two electrodes and the associated dielectric constant of the material of separation,

4. Any conductive materials in the near vicinity of the electrodes which may add to the total capacitance being sensed.

[0029] In a system using two separate sensors for the two electrodes with isolation between the electrodes, distinguishing between taps, grabs, and releases of the two electrodes is a fairly straight forward task. However, due to the behavior of a system using capacitively coupled electrodes 26, 28 and a single capacitive sensor 30 as shown in Figs. 1 and 2, the manner in which detections are made differs. Tables 1 through 3 show the possible detection states that can be accurately determined using the different sensing configurations.

[0030] As shown in ^Ί able 1. a dual sensor, dual electrode configuration can accurately distinguish up to 16 different states. A drawback is that the control algorithms must also process and determine Avhat state is currently present. Table 2 shows what states are possible to determine using a single sensor, dual electrode configuration with capacitively coupled electrodes as shown in Figs. ! and 2. for example.

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<td> 9ΤΔΤΡ</td><td colspan="3"> J Electrode 1</td><td colspan="3"> Electrode 2</td>

<td colspan="2"> ^TOUCHED</td><td> TAPPED</td><td> GRABBED</td><td> TOUCHED</td><td> TAPPED</td><td> GRABBED</td>

<td>¹</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td>

<td> 2</td><td> 0</td><td> G</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td>

<td> 3</td><td>_r„0 ....</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td><td> 0</td>

<td> 4 !</td><td> ΐ ⁰</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td><td> 1</td>

<td>⁶ ί</td><td> ’ Ü</td><td> 1</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td>

<td> 6 i</td><td> i 0</td><td> 1</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td>

<td colspan="2"> 7 § 0</td><td> 1</td><td> 0</td><td> 1</td><td> 0</td><td> 0</td>

<td> „u</td><td> ..-0-.</td><td> 1</td><td> 0</td><td> 1</td><td> 0</td><td> 1</td>

<td> 9 1</td><td>¹</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td>

<td> 10</td><td> 1</td><td> 0</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td>

<td> 11</td><td> 1</td><td> c</td><td> 0</td><td> 1</td><td> 0</td><td> 0</td>

<td> 12</td><td> 1</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td><td> 1</td>

<td colspan="2"> ’ Ί3 ·. I</td><td> 0</td><td> 1</td><td> 0</td><td> 0</td><td> 0</td>

<td colspan="2"> '14 '1 ;</td><td> 0</td><td> __1_</td><td> , 0</td><td> 1</td><td>⁰</td>

<td> '___io___</td><td> Ί</td><td> 0 ί</td><td> ; 1</td><td> : 1 ,</td><td>_: 0</td><td> ο ί</td>

'._J5__'i 0 ; 1_____. 1 0 (Tab:.j£ d

Detectable states using a dual sensor, dual electrode sensing configuration

<td colspan="3"> £ie/ Irode 1 (Direct)</td><td colspan="3"> Electrode 2 (Capacitive)</td><td rowspan="2"> STATE</td>

<td> TOUCHED</td><td> TAPPED</td><td> GRABBED</td><td> TOUCHED</td><td> ΤΑΡΡΕΌ</td><td> GRABBED</td>

<td> __0 _</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 0</td><td> 1</td>

<td> o“ '</td><td> 0</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td><td> 2</td>

<td> 0</td><td> 0</td><td> 0</td><td> 1</td><td> 0</td><td> 0</td><td> 3</td>

<td> __o‘_</td><td>¹_____o___</td><td> Γι</td><td> 1</td><td> 0___</td><td> 1</td><td> 4</td>

<td></td><td> F i _</td><td></td><td> n</td><td> —° _</td><td> c</td><td> 5</td>

<td> I</td><td> o </td><td> ”‘o</td><td> 0</td><td> ___c_</td><td> c</td><td> 6</td>

<td> 1 B» WVÎÎTiWiaii M</td><td></td><td> 1</td><td> 0</td><td> ο</td><td> c</td><td> 7</td>

( k AkX.A' J;

Detectable slates if Lag a single sensor configuration with capacitively coupled electrodes

<img file="CA2708577C_D0001.tif" />

Shown is a further reduction of states in Table 2 by eliminating the need to detect a tap of electrode ! and electrode 2 separately.

[0031] For the examnie sticwn in ïab! : I. t/neshoios lor each sensor/electrode can be determined such that at any tune trie sensor’s signal crosses said threshold, the electrode is defined as having been tc ;.ck a F the signa; cross-.’s rhe threshold for a defined period of time, as defined in the Definitions section above, flairs can be set as to whether the electrode has been tapped or grabbed. The exact states that appear for one electrode in this example can appear for the second electrode at the st .me time, in this configuration, each sensor can have its own set of

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DFC-P0086-WO thresholds for determining when die sensor has been touched and released. The setting of those thresholds can be determincc using a “dynamic baseline” determined from the raw sensor signal. A dynamic baseline is a calculated level based on the raw output level of the sensor. In this way, the “baseline” will tend to track the raw signal in the manner defined by the calculation of the baseline. Having independent thresholds is not possible for the case of a single sensor application using capacitively coupled electrodes.

[0032] fable 2 describes the detectable states that can be determined in the application shown in Figs. 1 and 2. Fig. - illustrates that if electrode 28 is touched for a long enough time to reach steady state amplitude, fiat the maximum achievable level at location 88 is not as great as the maximum achievable amplitude of electrode 26 which is directly coupled to the capacitive sensor 30 as illustrated at location 92. If the Upper Threshold 84 shown in Fig. 4 is adjusted such that it is above the maximum amplitude of electrode 28, but below the maximum amplitude of electrode 26, a determination can be made between the two. However, due to the rise times associated with each electrod s’ew rate, a tap event on the first electrode 26 may never cross the Upper Threshold 84 as iliustra^ed at location 90 and cannot be reliably distinguished between a tap of electrode 28 end a. tap of electrode 26. For this reason, the algorithm may be designed using a reduced subset of states shown in Table 2 as reflected in Table 3.

[0033] An example for this type of sensing is in the control of the electronic valve 22 for a plumbing application, The algorithm in question will do the following:

1. If the first electrode 26 (directly coupled electrode) is touched and the Electronic Valve 22 (from here on referred to as the EV,) is closed, the request will be made to open the EV 22.

2. If either elec trode 26 28 is tapped while the EV 22 is open, a request will be made to close the EV 22.

3. If first electrode 26 is grabbed and the EV 22 is open, no action will be taken on the EV 22.

4. If second electrode 28 is grabbed and the EV 22 is open, no action will be taken on the EV 22.

5. If second electrode 28 is grabbed and the EV 22 is closed, no action will be taken on the EV 22.

6. If either electrode 26, 28 is tapped while the EV 22 is closed, a request will be made to open the EV 22.

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-10[0034] Instead of trying io determine the difference between two electrodes 26, 28, rather, we concentrate on determining whether the sensor’s signal has crossed one of three dynamic thresholds 80, 82, 84 as shov/n in Fig. 4. Therefore, one more step in the algorithm needed for detecting the states of Table 2 may be saved to go from 7 possible states to 6. The algorithm will then obey the following rules: (Sensor’s Signal = SIG, UT = Upper Threshold, MT = Middle Threshold and LT Lower Threshold.)

1. If |SIG| > I UT| tot a period 1r. and ir > Τγ_Αρ min. and the EV is closed, a request will be made to open the EV This is reflected by states 5 and 6 of Table 3.

2. If |SIG| > |MT| for a period tp, has been released, and Tt_Ap_min < îr< Ttap.max, a request will be m e'e to dose the EV if it was previously open, or open the EV if it was previously closed. This is reflected by state 2 of Table 3.

3. If |SIG| > LMT| for a period U, the EV is open, and îr > T_Tap max, no action is taken. This is reflected by states 4 and 5 of Table 3.

4. If |S1G: &lt; V1T|, no action is taken, regardless of the state of the EV.

State Tables

Timer State

Timer

Enabled tp &lt; Gin

G:N tp &lt;

tMAX tp

<img file="CA2708577C_D0002.tif" />

(TABLE 4)

EV

ClosedI :_____________________________________________________Ϊi j Openj (TABLE 5)

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ISIGI State

<img file="CA2708577C_D0003.tif" />

f 0 |U I ' &lt; iSiG . ' (TABLE 6)

EV State

ISIGI State

<img file="CA2708577C_D0004.tif" />

; 0

<img file="CA2708577C_D0005.tif" />

: o

2-— : 3 t , ^{3 4}

NA j 7 j Q ^{NA 0} να ^ύ (TABLET)

NA i 0

NA , Ü

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<td> Action</td><td> Description</td>

<td> 0</td><td> No Action</td>

<td> 1</td><td> OPEN EV, Disable Tinter, îr = 3</td>

<td> 2</td><td> Disable Timer, r = 0</td>

<td> ; 3</td><td> Signal = inactive. Disable Timer, U = □</td>

<td> 4</td><td> Enable Tinier</td>

<td> 5</td><td> OPEN EV, Disable limer, Ir = β. Signai = Inactive</td>

<td> 6</td><td> CLOSE EV, Disable Tirnei, t_l: = I)</td>

<td> 7</td><td> Signal « Active</td>

(TABLE 8)

[0035] PROCESS FLOW

1. The states in ^r?.ble 4 are defined based on the current value of îr and whether or not the timer is enabled.

2. The EV State, as shov - in Table 5 is defined when a change of the EV state is made.

3. The |S1G| So O in Table 6 is adjusted based on the current value of the sensor signal in relation to the defined threshold levels, MT and UT. States 0 through 2 are for when the signal is defined as being “active,” and states 3 through 5 are for when the signal is defined as being “inactive.”

4. Table 8 is a listing of possible actions to be taken based on the conditions shown in Tabic 7.

5. Table ⁷ shows the various actions to be taken depending on the states of the EV, |SIG| State, and Timer State

[0036] bi another illustrated embodiment of the present invention, an algorithm is provided which detects a tap by a user on either the first or second electrodes 26, 28 based upon a change in a slope detected at a leading edge of the output signal from the capacitive sensor 30. Fig. 5 is a flow chart illustrating the steps performed by controller 24 to monitor the output of the capacitive sensor 30 and determine when the electrodes 26, 28 are tapped or grabbed for controlling the fluid flow.

[0037] Ίhe orocess starts at block 40. Initially no tabs or grabs are detected as illustrated at block 42. Controller 24 inputs sensor data from ’he capacitive sensor 30 as illustrated at block 44. Controller 24 then determines whether a positive slope of the output signal is detected at block 46. Leading edges of each of the touches at locations 86, 88, 90 and 92 in Fig. 4, for example, are detected as a positive slope occurrences. The detected slope must be large enough

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-1 βίο distinguish it from a gradual amplitude increase, such as when a user's hands approach the faucet, as illustrated at location 94 in Fig. 4, for example. In an illustrated embodiment, the slope must increase for about 10 counts in order for a positive slope to be detected at block 46. [0038] If a positive slope is not detected at block 46. controller 24 returns to block 44 to input additional sensor data. I fa positive slope is detected at block 46, controller 24 determines whether or not the positive slope is caused by an electromagnetic interference (EMI) event at block 48. For example, electromagnetic interference may occur if someone starts a dishwasher or other appliance near the faucet. Controller 24 may test for an EMI event by confirming that the positive slope sti JI exists at e later time interval such as, for example, 10 ms after the positive slope is initially defected. If the signal is still has a positive slope after 10 ms, controller 24 determines that the positive slope is caused by a touch of electrodes 26 or 28 and not by an EMI event.

[0039] If an EMI event is detected at block 48, controller 24 returns to block 44 to input additional sensor data. If an EMI event is not detected at block 48, controller 24 inputs additional sensor data at block 50. Controller 24 then determines whether a negative slope of the output signal is detected at block 52. Negative slopes of the output signal are illustrated, for example, at the trailing edges of portions 86. 88. 90 and 92 of the output signal of Fig. 4. If a negative slope is detected at block 52. controller 24 determines that a ’’tap” has been detected as illustrated at block 54. Controller 24 will then control the electronic valve 22 as discussed below in response to the tap Controller 24 then returns back to the start block 40 to monitor for the next touch of electrodes 26_; 28.

[0040] If a negative slope is not detected at block 52, controller 24 determines whether an elapsed time since rhe positive slope was detected at block 46 is less than a maximum elapsed time permitted for a tap event as illustrated at block 56. Illustratively, the maximum elapsed time for a tap e vent is about 300 ms. If the elapsed time is less than the maximum time for a tap event, controller 24 returns to block 50 to input additional sensor data. If the elapsed time at block 56 exceeds the maximum time permitted for a tap event at block 56, controller 24 detects a ’’grab” as illustrated at block 58. Next, controller 24 determines a type of grab that has occurred as illustrated at blocx 60. In the illustrated example, controller 24 distinguishes between a strong grab at b'oek 62 ami a weak grab at block 64. A strong grab at block 62 occurs when the user grabs the manual valve handle 14 used to adjust the flow or temperature of the fluid. A weak grab at block 64 occurs when the user grabs the spout 12. Controller 24 will then control the electronic valve 22 as discussed below in response to the detected strong or weak grab.

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DFC-PG086-WO

-14[0041] Once a determination is made between a strong grab and a weak grab, controller 24 sets a timer for grab release window values as illustrated at block 66. Controller 24 then inputs additional sensor data as illustrated at block 68. Next, controller 24 determines whether a grab release is detected within the release window at block 70. If not, controller 24 continues to input sensor data at block 68 If the grab release is detected at block 70, controller 24 returns back to start block 40 to monitor for the next touch of electrodes 26, 28. A grab release is detected by a negative slope of the output signal indicating that the user has released the electrode 26, 28.

[0042] In the embodiment of Fig. 5, the output from the capacitive sensor 30 does not have to reach a lower threshold level such as level 80 in Fig. 4 in order to be considered a tap event. Therefore, the embodiment of Fig. 5 provides improved detection of taps of the electrodes 26. 28. When the electrodes 26, 28 are grabbed for a longer period of time, the steady state amplitudes are reached at, for example, locations 88 and 92 of Fig. 4. These steady state levels are more easily predicted than the shorter duration taps as discussed above. In the embodiment of Fig. 5, the upper threshold level 84 is set to distinguished between strong grabs of the first electrode 26 on the handle 14 and weak grabs of the second electrode 28 on the spout 12. Once a grab is detected, if the amplitude of the steady state signal at location 88 is detected, it is determined that a grab of the spout 12 has occurred since the amplitude is below the upper threshold 84. If the output signal is above the upper threshold 84 during a grab as indicated at location 92, a strong grab of the handle 14 is detected.

[0043] The maximum amplitudes of the steady state signals when the first and second electrodes 26, 28 are grabbed at locations 92 and 88, respectively, of Fig. 4 may be adjusted. For example, the hub 32 may include a metallic portion which extends into the insulator 34. The metallic portion of the hub 32 overlaps a portion of the metal spout 12. The amount of overlap of metal between the hub 32 and the soout 12 effects the signal amplitude of the output signal of capacitively coupled electrode 26. Therefore, by reducing the metallic overlap between the hub 32 and the spout 12, the signal amplitude 88 in response to touches of the second electrode 28 coupled to the spout 12 may be reduced. Increasing the signal amplitude difference between the maximum signal output of the first and second electrodes 26, 28, facilitates distinguishing between strong grabs of the manual valve handle 14 and weak grabs of the spout 12.

[0044] Fig. 6 i s an operation state diagram for the second embodiment of the present invention. If the water is off, a tap of either the handle lever 14 or spout 12 will cause the water to turn on. A strong grab indicating that the handle 14 is grabbed will also turn the water on.

CA 02708577 2010-06-09

115-4055-U

DFC-P0086-WO

-15However, when the water is off, a weak grab of the spout 12 will not turn on the water. When the water is on. a tap of the lever handle 14 or spout 12 will turn the water off. However, when the water is on, strong and weak grabs of the handle 14 and spout 12 respectively, will not cause the water to turn off. Therefore, when the water is on, the user can adjust the location of the spout or grab the handle 14 and adjust the temperature or flow rate of the water without shutting the water off.

(0045] While the invention has been illustrated and described in detail in the drawings and foregoing description, the description is to be considered as illustrative and not restrictive in character. Only illustrated embodiments, and such alternative embodiments deemed helpful in 10 further illuminating the illustrated embodiments, have been shown and described. It will be appreciated that changes and modifications to the forgoing can be made without departing from the scope of the folio wing claims.