Abstract:
An automated plumbing fixture includes a position sensing device. The position sensing device includes a control module including a controller and a digital input connection, a capacitive position sensor module isolated from said control module, wherein said capacitive position sensor module includes a digital output, and a digital communication cable connecting said digital output to said digital input.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present disclosure is related generally to position sensing devices, and more specifically to a position sensing device for an automatic plumbing fixture. 
         [0002]    Position sensing automated devices, such as automatic faucets or drinking fountains, utilize position sensors built into the structure of the faucet to determine the position of a user relative to the metal fixture of the faucet. When the user is closer than a certain distance, the faucet activates and begins dispensing water. Similar arrangements are also utilized in drinking fountains and other plumbing fixtures. 
         [0003]    A common type of position sensing device used in these arrangements is a capacitive based sensor. The capacitive based sensor detects a capacitance between the metal fixture of the faucet and the person approaching or leaving the fixture. The strength of the capacitance varies depending on the distance between the person and the fixture according to known principles. In this way, a capacitance probe contacting the fixture can sense the capacitance and a controller can determine the position of the person based on this capacitance. 
       SUMMARY OF THE INVENTION 
       [0004]    Disclosed is an automated plumbing fixture including a position sensing device. The position sensing device includes a control module including a controller and a digital input connection, a capacitive position sensor module isolated from said control module, wherein said capacitive position sensor module includes a digital output, and a digital communication cable connecting said digital output to said digital input. 
         [0005]    These and other features may be best understood from the following drawings and specification. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic illustration of an automated faucet arrangement. 
           [0007]      FIG. 2  is a schematic illustration of a sensor module for use with the automatic faucet arrangement of  FIG. 1 . 
           [0008]      FIG. 3  is a schematic illustration of a control fixture for use with the automated faucet arrangement of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0009]      FIG. 1  illustrates a highly schematic automatic faucet arrangement  10 . The faucet arrangement  10  includes a faucet  20  for distributing water into a sink  12 . The faucet  20  is connected to a faucet pipe  30  that is, in turn, connected to a water supply such as a water main. Also included in the faucet assembly  20  is a sensor module  40  having a probe  42  for detecting a capacitance of the faucet  20  and a digital output wire  44  for transmitting the sensed capacitance value to a controller  50 . The controller  50  is located remote from the sensor module  40  in an enclosure  70 . Also contained in the enclosure  70  is a control valve  60 . The control valve  60  is controlled using a control signal from the controller  50  on a control wire  52 . 
         [0010]    Existing position sensing devices use an analog sensor wire placed along the faucet pipe  30  to sense the capacitance between a user and the faucet pipe  30  and faucet  20  arrangement. The analogue sensor wire is connected directly to the controller and provides the capacitance input. Because the communication wire is also the sensor wire (alternately referred to as a sensor probe), care is taken to ensure that the sensor wire contacts only the faucet pipe  30  and does not contact other conductive objects that would skew the sensor reading. Furthermore, the sensor wire must maintain contact with the faucet pipe  30  along a length of the faucet pipe  30 , and thus the sensor wire is not shielded. If the sensor wire contacts conductive objects aside from the faucet pipe  30 , the measurements of the capacitance probe become inaccurate. As a result, the controller of existing position sensor devices cannot be located within certain conductive housing types, such as a metal housing, or utilize conductive conduits to route the sensor wire. 
         [0011]    In the example of  FIG. 1 , the sensor module  40  includes a capacitive sensor that measures a capacitance between the faucet pipe  30  and a person approaching the faucet pipe  20  using a capacitance probe  42 . As the faucet pipe  30  and the faucet  20  are connected and are electrically conductive, the probe  42  senses the overall capacitance between the faucet  20  and the faucet pipe  30  arrangement and a user when the probe is connected to the faucet pipe  30  and provides the sensed value to a sensor module probe input. 
         [0012]    The capacitance of the faucet  20  and the faucet pipe  30  arrangement depends on a distance between the faucet  20  and a person approaching the faucet  20 . In particular, the approaching person forms one-half of a capacitor and the faucet  20  and the faucet pipe  30  arrangement forms the other half of the capacitor. The distance between the person and the faucet  20  is the dielectric gap of the formed capacitor. The capacitance of the formed capacitor is related to the distance between the person and the faucet according to known principles. By determining the capacitance, the controller can use these principles to determine the distance of the dielectric gap, and therefore, the distance between the user and the faucet  20 . 
         [0013]    The sensor module  40  converts the measured capacitance value to a digital form using an on-board processor and outputs the digital value through the digital communication wire  44  to the controller  50 . In some examples, multiple capacitance sensors are included in each sensor module  40 . In such an example, the controller  50  receives multiple digital capacitance values and uses an algorithm within the controller  50  to determine the actual distance. 
         [0014]    Once the controller  50  receives the capacitance values from the sensor modules  40 , and determines the distance between the person and the faucet  20 , the controller  50  outputs a valve control signal along a control signal wire  52  connecting the controller  50  to the valve  60 . The controller  50  is a programmable controller including a processor and a rewriteable memory and controls multiple different functions of the automatic faucet arrangement  10  based on the received capacitance values from the sensor module  40 . While the example of  FIG. 1  includes a single valve  60 , it is understood that more complicated flow control systems can be utilized and controlled in a similar manner using the above described scheme. 
         [0015]      FIG. 2  schematically illustrates a sensor module  140  that can be used in the embodiment of  FIG. 1  in greater detail. The sensor module  140  includes a processor  150  and a memory  158 . A capacitance probe input  152  of the processor  150  is connected to a capacitance probe  156 . The capacitance probe  156  is connected to a faucet shank  130  at a single point, thereby minimizing the chances of inadvertent electric contact altering the measured capacitance and skewing the position sensing. 
         [0016]    The capacitance probe  156  and the capacitance sensor  157  determine an analogue capacitance value of the capacitor formed between the user and the faucet  20 , and pass the analogue capacitance value to the processor  150 . The processor  150  converts the analogue capacitance value to a digital capacitance value and transmits the digital capacitance value to the controller  50  (see  FIG. 1 ). The memory  158  of the sensor module  140  can store simple instructions for the processor  150 , thereby enabling the processor  150  to perform conversions and other functions on the determined capacitance value prior to transmitting the value to the controller  50 . Alternatively, the memory  158  can be used to store/buffer multiple capacitance values to be sent to the controller  50  in packets. 
         [0017]    In an alternate example, the processor  150  within the sensor module  140  can perform all the tasks associated with measuring and processing the detected capacitance values from the position sensor resulting in a digital distance value determined at the sensor module  140 . Once the processor  150  has processed the values, the sensor module  140  outputs the digital distance value across the digital output line  154  to the remote controller. The remote controller then controls the flow of the faucet depending upon the determined distance value, rather than a measured capacitance value. 
         [0018]    By utilizing a sensor module  140  including a processor  150 , the sensor module  140  can be isolated from the controller  50  and perform simple processing on the measured values. The processor  150  further allows the sensor module  140  to be compactly located at the faucet  20  preventing inadvertent contact between the sensor probe and other conductive elements as a result of running a sensor wire to the controller  50 . Utilization of a digital communication wire  154  connecting the sensor module  140  and the controller  50 , instead of the analog sensor wire of existing position sensing devices, allows the controller  50  to be placed within a fixture using shielded walls, such as metal plumbing fixtures or similar enclosures, without impacting performance of the position sensing device. 
         [0019]      FIG. 3  schematically illustrates an example control fixture  200 . The control fixture  200  includes a conductive metal housing  210  containing a controller  220 . The controller  220  includes a digital input  222  that receives a digital signal from the remote position sensor module  140  illustrated in  FIG. 2 . The controller  220  includes a memory, a processor, and a user input mechanism that allows a controller  220  to be programmed by an installer. The digital input  222  can be a bundle of digital input signals  292  as shown, or a single digital input. The digital input  222  is a shielded digital communication line and is routed to the controller in a conduit. In some examples the conduit is constructed of metal or another conductive substance. 
         [0020]    The controller  220  also includes an output bundle  224  that contains multiple output signals  224 A/ 224 C each of which has a dedicated output wire within the bundle  224 . Each output wire  224 A/ 224 C controls a separate component within the fixture  200 . Control wire  224 A provides a control signal that controls a flow control valve  230 , and control wire  224 C provides a solenoid control signal to a solenoid  240 . Similarly, the controller  220  can control any known flow control devices within a fixture  200  using known flow control techniques. Bundled with the control wires  224 A/ 224 C is a power supply wire  224 B that connects a power supply  298  to the controller  220 . 
         [0021]    As described above, the controller  220  receives a digital value representing the distance between the user and the faucet, and determines an action to perform in response. In the illustrated example, the controller  220  operates the solenoid  240  and opens the flow control valve  230  when the user is within a set distance threshold, thereby turning on the faucet. When the user exits the threshold distance, the controller  220  turns off the faucet by reversing the control commands. The controller  220  can be programmed with any desired response to a distance measurement, and the programming is stored in the controller&#39;s re-writable memory. 
         [0022]    While the above description relates to an automatic faucet arrangement, it is understood that similar arrangements using a remote sensor module and a controller within a plumbing fixture can be utilized in any plumbing arrangement and still fall within this disclosure. 
         [0023]    Although an embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.