Patent Publication Number: US-8984679-B2

Title: Lavatory system

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     The present application is a continuation of, and claims the benefit of priority as available under 35 U.S.C. §121 to, co-pending U.S. patent application Ser. No. 11/858,800, having a filing date of Sep. 20, 2007, titled “LAVATORY SYSTEM,” which is a divisional of U.S. patent application Ser. No. 11/041,882, having a filing date of Jan. 21, 2005, titled “LAVATORY SYSTEM,” which claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/538,583, having a filing date of Jan. 23, 2004, titled “LAVATORY SYSTEM,” and which claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Application No. 60/602,585, having a filing date of Aug. 18, 2004, titled “LAVATORY SYSTEM,” the entire disclosures of which are hereby incorporated herein by reference. 
    
    
     FIELD 
     The present inventions relate generally to a lavatory system. The present inventions also relate to a lavatory system having a control system suitable for providing “hands-free” operation of one or more fixtures (e.g., sprayheads, faucets, showerheads, soap or lotion dispensers, hand dryers, flushers for toilets and/or urinals, emergency fixtures, etc.) within the lavatory system. The present inventions further relate to a lavatory system having a photovoltaic system for providing electrical energy one or more electronic fixtures within the lavatory system and/or for providing electrical energy to a control system coupled to the fixtures. 
     BACKGROUND 
     It is generally known to provide a lavatory system having at least one fixture that conventionally requires manual manipulation by a user in order to operate. It is further known to provide an electrical and/or electronic control system with such a fixture for providing “hands-free” operation of the fixture. Not requiring a user to physically contact or touch the fixture for its operation may be desirable for various sanitary and/or accessibility considerations. 
     A power source is necessary when using an electronic and/or electrical control system to control a fixture. When available and desirable, power is commonly provided by an AC power line. However, when not available or not desirable, alternative power sources are utilized. Known alternative power sources include energy storage elements such as batteries and capacitors. However, control systems that use such energy storage elements have disadvantages, including having a power source with a relatively finite operating life that often must be periodically changed, reenergized, or otherwise maintained. 
     It would be advantageous to provide a lavatory system for use in commercial, educational, or residential applications, having one or more fixtures and a control system for enabling “hands-free” operation of the fixtures wherein the control system is powered by means other than an AC power line (e.g., energy storage element, etc.). It would also be advantageous to provide a control system for use with a lavatory system that can prolong the operating life of an energy storage element by reducing or minimizing the required power consumption of the control system. It would further be advantageous to provide a control system that minimizes or reduces power consumption by increasing the speed at which the control system processes a signal representative of the environment near the fixture (a sensing region). It would further be advantageous to provide a lavatory system having a photovoltaic system that can provide electrical energy to a control system and/or a fixture of the lavatory system. It would further be advantageous to incorporate photovoltaic cells into the support structure of a lavatory system (such as a usable surface). It would further be advantageous to provide a power management system providing for the efficient use of electrical energy generated by a photovoltaic system. 
     Accordingly, it would be desirable to provide for a lavatory system having one or more of these or other advantageous features. 
     SUMMARY 
     An exemplary embodiment relates to a lavatory. The lavatory includes at least one wash station, at least one electrically operated fixture associated with the wash station, a control system configured to control a flow of a fluid through the at least one electrically operated fixture, a power source selectively coupled to the control system, and a power management system coupled to the power source to control the power provided to the control system. The power management system includes a detector configured to monitor the output voltage of the power source, and a switch configured to electrically disconnect the power source from the control system when the output voltage of the power source drops below a predetermined level. 
     Another exemplary embodiment relates to a control system for use with a lavatory system having at least one wash station and at least one electrically operated fixture. The control system includes a detection system, a fixture actuation system coupled to the detection system and configured to control a flow of a fluid through the fixture based upon a signal received from the detection system, a power source selectively coupled to the detection system, and a power management system coupled to the power source to control the power provided to the detection system. The power management system includes a detector configured to monitor the output voltage of the power source, and a switch configured to electrically disconnect the power source from the control system when the output voltage of the power source drops below a predetermined level. 
     Another exemplary embodiment relates to a power supply system for a lavatory system having a control system for operating a fixture. The power supply system includes a power source configured to be electrically coupled to the control system and to provide an output voltage. The power supply system also includes a power management system coupled to the power source. The power management system includes a detector configured to monitor the output voltage of the power source, and a switch configured to electrically disconnect the power source from the control system when the output voltage of the power source drops below a predetermined level. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a lavatory system according to an exemplary embodiment, shown as a washing station. 
         FIG. 2  is a perspective view of a lavatory system having a photovoltaic system according to an exemplary embodiment. 
         FIG. 3  is a top view of the lavatory system of  FIG. 2  showing photovoltaic cells coupled to an upper portion of the lavatory system. 
         FIG. 4  is a partially exploded perspective view of the photovoltaic system of  FIG. 2 . 
         FIG. 5  is a partial cross section view of the lavatory system shown in  FIG. 2  taken along the line  5 - 5 . 
         FIG. 6  is an exploded perspective view of an upper portion of a lavatory system showing a photovoltaic system according to another embodiment. 
         FIG. 7  is a partial cross section of the upper portion of the lavatory system shown in  FIG. 6  showing a photovoltaic cell unit coupled to the lavatory system. 
         FIG. 8  is a schematic block diagram a control system for use with the lavatory system shown in  FIG. 1  to provide for the operation of the fixtures. 
         FIG. 9  is a schematic block diagram of a power supply system of the control system shown schematically in  FIG. 8  according to an exemplary embodiment. 
         FIG. 10  is a schematic block diagram of a power supply system of the control system shown schematically in  FIG. 8  according to another exemplary embodiment. 
         FIG. 11  is a schematic block diagram of a detection system of the control system shown schematically in  FIG. 8  according to an exemplary embodiment. 
         FIG. 12  is a schematic block diagram of a transmitter of the control system shown schematically in  FIG. 11  according to an exemplary embodiment. 
         FIG. 13  is a schematic block diagram of a receiver of the control system shown schematically in  FIG. 11  according to an exemplary embodiment. 
         FIG. 14  is a schematic block diagram of a fixture actuation system of the control system shown schematically in  FIG. 8  according to an exemplary embodiment. 
         FIG. 15  is a detailed schematic block diagram of the control system of  FIG. 8  according to an exemplary embodiment. 
         FIG. 16  is a detailed schematic block diagram of the control system of  FIG. 8  according to another exemplary embodiment. 
         FIG. 17  is a detailed schematic block diagram of a power management system of the photovoltaic system of  FIG. 16  according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring generally to the FIGURES, a lavatory system  10  with components is shown according to exemplary embodiments.  FIG. 1  shows lavatory system  10  as a washing station suitable for providing a cleansing area for one or more users. Lavatory system  10  is shown as including a pair of fixtures  14  having outlets (e.g., nozzles, diffusers, etc.) directed towards a basin  18  which is supported by a base or a support structure  12 . Support structure  12  is provided an upper portion  16  by which fixtures  14 , and/or other components, may be placed upon or coupled thereto. Upper portion  16  is further shown as including a platform or shelf  20  which provides a relatively flat surface (e.g., ledge, countertop, etc.) that can be used by a user to conveniently hold various objects (e.g., toiletries, beverage containers, personal items, etc.). 
     According to an exemplary embodiment, lavatory system  10  includes a control system  50  for controlling the operation of fixtures  14 . Preferably, fixtures  14  are “touchless” fixtures meaning that a user can operate the fixtures without physically contacting the fixtures and/or an interface coupled to the fixtures (i.e., “hands-free” operation). In this manner, lavatory system  10  can overcome sanitation and/or accessibility limitations often associated with conventionally used fixtures. Control system  50  monitors a defined sensing region (an area adequately proximate to fixtures  14  in which a user of the fixture is likely to be positioned) for the presence of an object (e.g., a user, etc.) and controls the operation of fixtures  14  accordingly.  FIG. 8  shows a block diagram representative of control system  50  according to an exemplary embodiment. Control system  50  includes a power supply system  100 , a detection system  200 , and a fixture actuation system  500 . Control system  50  is configured to reduce power consumption in an effort to prolong the useful operating life of a power source having an finite operating life (such as a battery). Power consumption is reduced by shortening the time interval (i.e., a sample period) for which detection system  200  is monitoring the sensing region and by increasing a speed at which detection system  200  processes a signal representative of status of the sensing region. Increased processing speed allows detection system  200  to take extended “sleep periods” which conserve power. “Sleep periods” include periods wherein detection system  200  is substantially not consuming any power, and/or periods wherein detection system  200  is consuming a reduced amount of power. 
     According to another exemplary embodiment, lavatory system  10  includes a photovoltaic system  600  capable of converting light energy to electrical energy. Photovoltaic system  600  can be used to power fixtures  14  and/or a control system providing for the “hands-free” operation of fixtures  14  (such as control system  50 ).  FIGS. 2 through 4  and  16  through  18  show photovoltaic system  600  and components thereof according to exemplary embodiments. Referring particularly to  FIG. 2 , photovoltaic system  600  is shown as including one or more photovoltaic cells  602  (such as an array of cells) coupled to support structure  12  of lavatory system  10 . Photovoltaic cells  602  may be supported by, mounted to, contained within, and/or integrally formed with a portion of support structure  12 . Preferably, photovoltaic cells  602  are provided at shelf  20  of upper portion  16  of support structure  12  in an effort to maximize the exposure of photovoltaic cells  102  to the ambient light. Preferably, the addition of photovoltaic cells  602  to shelf  20  does not significantly limit the functionality of shelf  20  as a usable surface for a user. 
     Photovoltaic cells  602  are electrically coupled to fixtures  14  and/or a control system providing for the operation of fixtures  14 . According to an exemplary embodiment, photovoltaic system  600  further includes a power management system  650  providing for an efficient use of the electrical energy generated by photovoltaic cells  602 .  FIGS. 17 and 18  show power management system  650  and components thereof according to exemplary embodiments. Power management system  650  generally includes an energy storage element  660  configured to receive and store electrical energy generated by photovoltaic cells  602 , a detector (shown as a voltage detector  670 ) for monitoring the level of ambient light surrounding lavatory system  10  (e.g., by monitoring the energy stored in energy storage element  660 , etc.) to recognize periods of time when it is unlikely that lavatory system  10  will be used (e.g., when the ambient light is turn off or otherwise reduced), a switch  680  capable of electrically disconnecting energy storage element  660  from control system  50  when voltage detector  670  sends an output signal indicating that given the level of ambient light surrounding lavatory system  10  it is unlikely that lavatory system  10  will be used, and a voltage regulator  690  for adjusting the voltage being sent to control system  50 . According to various alternative embodiments, power management system may be used without photovoltaic cells  602  to electrically disconnect an energy storage element (such as a battery) from control system  50 . 
     Referring back to  FIG. 1 , lavatory system  10 , is intended for commercial, educational, medical, and/or residential use and to be readily installed in a number of locations and environments including, but not limited to, restrooms, locker rooms, break rooms, surgical prep rooms, kitchens, or the like. For purpose of this disclosure, the phrase “lavatory system” is used generally to refer to any cleansing or other sanitary system or station, and is not intended to be limited to the washing station shown. For example, the various alternative embodiments of lavatory system  10  may include, but are not limited to, toilets, urinals, showers, wash fountains, emergency wash stations (e.g., drench showers, eye wash systems, etc.), or alternative washing stations. 
     Fixtures  14 , shown as a pair of sprayheads, are configured for directionally dispensing (e.g., spraying, discharging, spending, etc.) a fluid (e.g., water, etc.). According to various alternative embodiments, lavatory system  10  may include a variety of other fixtures instead of, or in combination with, fixtures  14  including, but not limited to, faucets, soap or lotion dispensers, hand dryers, showerheads, flushers for toilets and/or urinals, emergency fixtures, etc. Fixtures  14  are shown coupled to support structure  12 , but alternatively may be supported relative to lavatory system  10 . For example, according to an alternative embodiment, fixtures  14  may be coupled to a structure such as a wall or partition rather than support structure  12 . According to a preferred embodiment, fixtures  14  are coupled to upper portion  16  of support structure  12  with their outlets directed in an outwardly and downwardly manner towards basin  18 . 
     Fixtures  14  are adapted for being in fluid communication with a fluid supply via a conduit system (not shown) which is likely to include one or more sections of piping or tubing. Each fixture  14  may be independently coupled to a fluid supply, or alternatively, may be coupled to a common or shared fluid supply (e.g., through use of a manifold, etc.). Preferably lavatory system  10  is a multiple station lavatory system wherein fixtures  14  are sufficiently spaced apart in a lateral direction relative to support structure  12  for providing more than one cleansing area. According to various alternative embodiments, any number of fixtures  14  may be used for providing any number of cleansing areas. 
     Lavatory system  10  further includes a fluid collection receptacle (shown as wash basin  18 ) for collecting fluid that is discharged from fixtures  14 . Wash basin  18  is likely to include one or more fluid drains  19  (shown in  FIG. 3 ) which allow wash basin  18  to be emptied of fluid collected therein. Preferably, wash basin  18  is a substantially continuous receptacle for servicing both fixtures  14 , but alternatively, may be provided as a divided receptacle, or further still, as two separate or isolated receptacles (one for each fixture  14 ). Wash basin  18  is surrounded by a relatively flat surface (e.g., platform, ledge, countertop, tabletop, etc.), shown as a deck  17 . Deck  17  may be integrally formed with wash basin  18  (provided as a one-piece member), or alternatively, may be a separate component. According to various alternative embodiments, fixtures  14  may be coupled to deck  17 , which can also be used to support a variety of other fixtures. Wash basin  18  is shown as being supported by support structure  12 , but according to an alternative embodiment, may be supported by a partition or any other suitable wall structure. 
     Support structure  12  is shown as including upper portion  16  and a lower portion  22 . Upper portion  16  is positioned above wash basin  18  and is provided with shelf  20 . Lower portion  22  is configured to at least partially support deck  17  and/or wash basin  18 . Preferably, lower portion  22  is configured to conceal the conduit system fluidly coupling fixtures  14  to the fluid supply. Lower portion  22  may include one or more access panels (such as a cabinet door) for allowing access to the components of lavatory system  10  (e.g., conduit system, fixture control system, etc.). According to various alternative embodiments, lower portion  22  may be eliminated if deck  17  and/or wash basin  18  can be sufficiently supported by other means, such as by mounting deck  17  and/or wash basin  18  to a wall in a cantilever manner and/or by supporting deck  17  and/or wash basin  18  with a structure provided from above lavatory system  10 . 
       FIGS. 8 through 16  show control system  50  and components thereof according to exemplary embodiments. Control system  50  provides for the “hands-free” operation of fixtures  14 . Control system  50  is a relatively “low” power system that is configured to avoid false readings that limit the effectiveness of conventional control systems. Control system  50  generally includes power supply system  100 , detection system  200 , and fixture actuation system  500 . Power supply system  100  provides an operating voltage to the various elements/components of control system  50 , while detection system  200  monitors an area (i.e., sensing region, zone of detection, etc.) adjacent fixture  14  and provides an output signal to fixture actuation system  500  which in turn activates or deactivates a valve (e.g., a solenoid valve  502 ) for controlling the flow of a fluid through fixtures  14 . 
     Control system  50  can be mounted to lavatory system  10  in a variety of ways and at a variety of positions. Preferably, the majority of the circuitry of control system  50  is provided beneath wash basin  18  and is concealed from the view of a user by lower portion  22  of support structure  12 . According to various alternative embodiments, control system  50  may be provided at a position that is remote from lavatory system  10 . A sensory window  24  (shown in  FIG. 1 ) is provided on lavatory system  10  to house and/or protect a transmitter  220  and an receiver  230  of detection system  200 . Lavatory system  10  is shown as having a separate sensory window  24  for each fixture  14 . According to various alternative embodiments, a common sensory window  24  may be provided for housing and/or protecting components of detection system  200  used to control both fixtures  14 . Sensory window  24 , in combination with transmitter  220  and receiver  230  of detection system  200 , define the sensing region in which an object must enter in order for control system  50  to activate fixtures  14 . The size of the sensing region can be varied depending on the particular application. 
     Referring particularly to  FIGS. 9 ,  10 ,  15  and  16 , power supply system  100  generally includes a power source  102 , a voltage regulator  104 , a charging circuit  106 , an energy storage element  108 , and a voltage detector  110 . Power supply system  100  is configured to provide a first output, shown as a system supply voltage  114 , for providing electrical energy to components of detection system  200 , a second output, shown as a fixture supply voltage  116 , for providing electrical energy to fixture actuation system  500 , and a third output, shown as a status signal  118 , representative of power level of energy storage element  108 . According to various alternative embodiments, power supply system  100  may include any number of outputs depending upon the requirements of control system  50  and/or lavatory system  10 . 
     Control system  50  is advantageously configured for use in applications for which access to a conventional AC power line (requiring a hard-wired connection) is not readily available or is otherwise undesirable to use (e.g., not cost effective to access, etc.). While a conventional AC power line may be used alone or in combination as power source  102 , preferably power source  102  is an energy storage element having a relatively finite service or operating life such as a battery, a photovoltaic cell energizing a capacitor (shown in  FIG. 10 ), or the like. According to a one embodiment, power source  102  is a lithium battery having a voltage between approximately 4 volts and approximately 7 volts. According to various alternative embodiments, power source  102  may be provided by any suitable battery having a range of suitable voltages, and/or may further include a supplemental (e.g., secondary, etc.), a startup, and/or a backup power source. 
     According to a particularly preferred embodiment, power source  102  has an output voltage of approximately 7 volts. Voltage regulator  104  is configured to adjust the output voltage of power source  102  to a predetermined operating voltage that is compatible with the components of detection system  200  before the electrical energy is outputted as system supply voltage  114 . According to an exemplary embodiment, voltage regulator  104  provides a relatively stable operating voltage of approximately 3.3 volts that is subsequently distributed as system supply voltage  114  to various components of control system  50  requiring electrical energy (shown as system supply voltage inputs  120 ). According to various alternative embodiments, voltage regulator  104  may be eliminated if the voltage of power source  102  equals the voltage needed for system supply voltage  114 . 
     Fixture supply voltage  116  (the second output voltage of power supply system  100 ) provides an operating voltage for the activation and deactivation of a valve controlling the flow of a fluid from fixtures  14 . Fixture supply voltage  116  is outputted from energy storage element  108 , which is preferably provided by a storage capacitor. Energy storage element  108  stores electrical energy until needed to actuate the valve controlling the flow of the fluid from fixtures  14 . According to an exemplary embodiment, energy storage element  108  has a capacitance of between approximately 10 millifarads (mF) to approximately 10 F. According to a preferred embodiment, energy storage element  108  is provided by a single super capacitor having a capacitance of approximately 60 mF, but alternatively, may be provided by a plurality of capacitors (the combination of which provides the desired capacitance and voltage rating). According various alternative embodiments, energy storage element  108  may be configured to have a variety of capacitances depending upon the particular application. 
     To ensure that energy storage element  108  contains a sufficient amount of electrical energy to turn fixtures  14  on and/or off (i.e., enough electrical energy to actuate a solenoid valve  502 ), voltage detector  110  is provided for monitoring the power level of energy storage element  108 . Voltage detector  110  monitors energy storage element  108  to ensure that the voltage of energy storage element  108  does not drop below a preset threshold or baseline voltage. According to a preferred embodiment, the baseline voltage of energy storage element  108  is set at approximately 4.5 volts (meaning that if the voltage of energy storage element  108  drops below 4.5 volts, energy storage element will be charged sufficiently charged). 
     Voltage detector  110  sends status signal  118  (the third output of power supply system  110 ) to detection system  200 , preferably a computing device (shown as a central processing unit (CPU)  240 ) of detection system  200 , representative of power level of energy storage element  108 . If status signal  118  indicates that the power level of energy storage element  108  has dropped below the preset baseline voltage, CPU  240  sends an output signal  122  to charging circuit  106  which is in turn activated to charge energy storage element  108 . Power supply system  100  may optionally include an indicator  112  (shown in  FIGS. 12 and 13 ) to provide for a visual display (e.g., a continuous or flashing light, etc.) when energy storage element  108  is being charged by charging circuit  106 . 
     Referring generally to  FIGS. 11 through 13 ,  15 , and  16 , detection system  200  generally includes a computing device (shown as a central processing unit (CPU)  240 ) and a sample and hold circuit  210  to which a sensory device with a transmitter  220  and a receiver  230  is connected thereto. Detection system  200  further includes a pulse regulator circuit  260  for shortening the time interval of the sample period. Detection system  200  monitors the sensing region and provides output signal to fixture actuation system  500  indicating whether solenoid valve  502  should be opened or closed. 
     Referring particularly to  FIGS. 11 and 15 , CPU  240  is configured to support and execute a program to control the components of control system  50 . CPU  240  is powered by system supply voltage  114  and is shown as having a first output  242  for controlling transmitter  220 , a second output  244  for sending an operating voltage to receiver  230 , a third output  246  for providing a “valve closed” signal to fixture actuation system  500 , a fourth output  248  for providing a “valve open” signal to fixture actuation system  500 , a fifth output  250  for controlling charging circuit  106  of power supply system  100 , a sixth output  252  for activating indicator  112  when charging circuit  106  is charging energy storage element  108 , and a seventh output  254  for providing an operating voltage to components of detection system  200 . CPU  240  is further shown as having a first input  241  representative of the operating state of fixtures  14 , a second input  243  representative of the voltage level of energy storage element  108 , and a third input  245  representative of the level of infrared light within the sensing region. According to various alternative embodiments, CPU  240  may include any number of outputs and inputs to meet the requirements of the particular application. 
     CPU  240  is configured to operate at a relatively fast processing speed in comparison to CPUs used in known control systems which also rely upon a power source having a relatively finite operating life. By utilizing a CPU having a relatively fast processing speed, control system  50  is able to conserve power. Although a faster CPU requires more power than conventionally used CPUs (those having a clock rate of less than 32 kHz), the faster CPU is able to process third input  245  and compare that value with an established baseline value to determine what output (third output  246  or fourth output  248 ), if any, should be sent to fixture actuation system  500  faster than conventionally used CPUs. 
     According to an exemplary embodiment, CPU  240  has a clock rate greater than approximately 32 kilohertz (kHz). According to a preferred embodiment, CPU  240  has a clock rate within the range of approximately 32 kHz to approximately 20 megahertz (MHz). According to a particularly preferred embodiment, CPU  240  has a clock rate of approximately 4 MHz. Since a 4 MHz CPU can process and compare the signal faster than a 32 kHz CPU, the sleep period of the 4 MHz CPU will be longer than that of the 32 kHz CPU. A longer sleep period will prolong the operating life of energy storage element  108 . The sleep period may include periods wherein CPU  240  requires substantially no power and/or periods wherein CPU  240  requires a reduced amount of power. For example, CPU  240  may be configured to operate between varying frequencies rather than just between an “on” and “off” operational state. Accordingly, CPU  240  may have a clock rate of 4 MHz while a sample of the sensory region is being obtained, while having a clock rate of only 32 kHz between sampling periods to allow for reduced power consumption. In such a configuration, the period during which the 4 MHz CPU operated at 32 kHz may constitute the sleep period. 
     Referring generally to  FIGS. 11 through 13 ,  15 , and  16 , transmitter  220  is configured to emit a signal into the sensing region, while receiver  230  is configured to measure (e.g., capture, monitor, etc.) the signal in the sensing region. Preferably, transmitter  220  is configured to emit pulses of infrared light into the sensing region, while receiver  230  is configured to measure the level of infrared light in the sensing region. According to various alternative embodiments, transmitter  220  and receiver  230  may be configured as a radar sensor, a sonar sensor, or any other suitable sensory device. 
     Receiver  230  may be operated independently of transmitter  220  (to measure a background level of infrared light) and/or may be operated in conjunction with transmitter  220  (to measure the amount of reflected infrared light in the sensing region to detect the presence of an object (e.g., a user)). When a user enters the sensing region, at least a portion of the infrared light emitted from transmitter  220  will be reflected by the user and detected by receiver  230 . A signal representative of the level of infrared light in the sensing region is sent to CPU  240  which in turn uses the signal to determine whether fixture actuation system  500  should be actuated. If an object is detected, CPU  240  will send a signal from output  248  to fixture actuation system  500  to activate a valve (e.g., solenoid valve  502 ) allowing for the flow of a fluid from at least one of fixtures  14 . 
     Referring particularly to  FIG. 12 , transmitter  220  is shown as including a power storage circuit  222 , a current limiting switch  224 , and an light emitting diode (LED)  226 . Power storage circuit  222  receives and stores a sufficient amount of power for activating LED  226 . According to an exemplary embodiment, power storage circuit  222  includes a capacitor that is charged by system supply voltage  114  outputted by power supply system  100 . Current limiting switch  224  is provided for regulating the maximum current being provided to LED  226 . According to an exemplary embodiment, current limiting switch  224  limits the current going to LED  226  to between approximately 700 and 800 milliamps. 
     According to an exemplary embodiment, one transmitter  220  having one LED  226  is provided for each fixture  14 . According to various alternative embodiments, any number of transmitters  220  (having any number of LEDs  226 ) can be used to emit pulses of infrared light into the sensing region of the respective fixture  14 . According to an exemplary embodiment, LED  226  is supported at a position above fixtures  14  so that a fluid flow discharging from fixtures  14  does interfere with (e.g., reflect, etc.) the pulses of infrared light being emitted by LED  226 . Preferably, LED  226  is protected behind sensory window  24  (see  FIGS. 1 and 2 ) that is provided in upper portion  16  of support structure  12 . The placement of LED  226  and/or sensory window  24  and the method of supporting LED  226  and/or sensory window  24  relative to support structure  12  may change depending on the fixtures and configuration of lavatory system  10 . 
     Referring particularly to  FIG. 13 , receiver  230  is shown as including a photodiode  232  and a photodiode amplifier  234 . Photodiode  232  captures the level of infrared light in the sensing region (including levels of infrared light in the ambient light and/or levels of infrared light from transmitter  220 ). According to an exemplary embodiment, photodiode  232  is positioned adjacent to LED  226 . According to various alternative embodiments, receiver  230  may include any number of photodiode  232  for capturing the level of infrared light in the sensing region, and can be positioned near and/or at a distance from LED  226 . Photodiode  232  generates an output signal  236  representative of level of infrared light in the sensing region. Output signal  236  is fed into photodiode amplifier  234 , which is configured to amplify the current coming from photodiode  232  (output signal  236 ) into an analog voltage and to provide buffering for the resultant signal. The analog voltage representative of the level of infrared light in the sensing region is then sent to sample and hold circuit  210 . 
     Referring to  FIGS. 11 ,  15 , and  16 , sample and hold circuit  210  is configured to receive and store a first voltage representative of the level of infrared light in the sensing region when transmitter  220  is not activated and a second voltage representative of the level of infrared light in the sensing region when transmitter  220  is activated. Sample and hold circuit  210  is shown as including a first output  211  for outputting the first voltage to a first buffer  212  and subsequently a difference amplifier  213 . Sample and hold circuit  210  is further shown as including a second output  214  for outputting the second voltage to a second buffer  215  and subsequently difference amplifier  213 . Sample and hold circuit  210  includes one capacitor and one corresponding switch for each the first voltage (representative of the level of infrared light in the sensing region when transmitter  220  is not activated) and the second voltage (representative of the level of infrared light in the sensing region when transmitter  220  is activated). Preferably, the storage capacitors of sample and hold circuit  210  are relatively small so that the capacitors can charge quickly thereby allowing the input signals from photodiode amplifier  234  to be continually recognized. According to a particularly preferred embodiment, storage capacitors having a capacitance of approximately 1000 picofarads (pF) are used for the storage capacitors of sample and hold circuit  210 . According to various alternative embodiments, storage capacitors having other capacitances may be used. 
     Referring still to  FIGS. 11 ,  15 , and  16 , pulse regulator  260  establishes the time interval of a sample period for sample and hold circuit  210 . For purposes of this disclosure, the term “sample period” is used generally to refer to the period of time needed for sample and hold circuit  210  to capture and hold both the background level of infrared light and the background level of infrared light plus the reflected level of infrared light. Pulse regulator  260  provides for a shorten sample period (a sample period of approximately 1.5 microseconds (μs)) that advantageously allows lavatory system  10  to be used in environments wherein the ambient light and/or other signal transmitters at least periodically emit levels of infrared light. For example, it is generally known to use fluorescent lamps having a frequency range between 50 Hertz (Hz) and 110 kilohertz (kHz). If a measurement of the sensing region is taken over a relatively long period of time, the measurement may include a high peak value and a low peak value of the fluorescent light which may cause control system  50  to misinterpret the change in the level of infrared light in a sensing region. Shortening the sample period decreases the likelihood of a false reading caused by interfering infrared light. 
     Pulse regulator  260  is shown as generally including a first monostable  262  and a second monostable  264 . First monostable  262  includes an input  266  for receiving a signal from output  242  of CPU  240  for starting a timing period, a first output  268  for sending a signal to sample and hold circuit  210 , and a second output  270  for providing a signal to second monostable  264 . Second monostable  264  includes an input  272  for receiving a signal from second output  270  from first monostable  262  and an output  274  for providing a signal to sample and hold circuit  210  and transmitter  220 . Together, first monostable  262  and second monostable  264  provide a dual monostable multivibrator between an output pulse from CPU  240  and transmitter  220  for shortening the sample period. 
     Referring particularly to  FIGS. 14 through 16  fixture actuation system  500  receives an input signal from detection system  200  indicating whether to change the operating state of fixtures  14 . Fixture actuation system  500  is shown as generally including a valve, shown as a solenoid valve  502 , fluidly coupled to a fluid line between the fluid source and the outputs of fixtures  14 . Solenoid valve  502  switches between an first or open position, wherein fluid is able to discharge from fixtures  14 , and a second or closed position, wherein solenoid valve  502  is configured to block the fluid line to prevent fluid from discharging from fixtures  14 . 
     According to a preferred embodiment, solenoid valve  502  is a latching valve including a cylinder enclosing a piston having a plunger disposed around a first end and a magnet positioned at the top of the first end. In the closed position, the plunger is seated against a diaphragm to prevent fluid from exiting fixture  14 . In the open position, the plunger is unseated from the diaphragm and moved towards the top of the cylinder to allow for the flow of a fluid. The plunger is held in the open position by the magnet. 
     Fixture actuation system  500  is further shown as including a switching device, shown as an H-Bridge  504 , for controlling the positioning of solenoid valve  502  by reversing the polarity of the current sent to solenoid valve  502  from energy storage element  108 . H-Bridge  504  is shown as including a first input  506  for receiving the “valve close” signal from output  246  of CPU  240 , a second input  508  for receiving the “valve open” signal from output  248  of CPU  240 , and a third input  510  for fixture supply voltage  116  from energy storage element  108  of power supply system  100 . H-Bridge  504  is further shown as including a first output  512  for providing a signal to solenoid valve  502  and a second output  514  for providing a signal to CPU  240  representative to the operational state of solenoid valve  502 . Before reaching CPU  240 , the signal passes through an amplifier  516 . 
     According to various alternative embodiments, CPU  240  may be configured for providing “valve open” signal to H-Bridge  504  without providing a “valve closed” signal. In this manner, solenoid valve may be closed by utilizing a timer to control the duration that solenoid valve  502  in the open position. 
     Operation of control system  50  is described according to a particularly preferred embodiment with reference to lavatory system  10 . In operation, CPU  240  supports and executes a program to control the components of control system  50  by performing a series of statuses in a continuous loop. Upon startup, CPU  240  enters an initial status (e.g. power up, startup, etc.) wherein CPU  240  ensures that solenoid valve  502  is in the second or closed position so that fluid is not being discharged from fixtures  14 . CPU  240  ensures that solenoid valve  502  is in the closed position by providing the “closed valve” signal from output  246  to H-Bridge  504  of fixture actuation system  500 . During this initial status, CPU  240  further receives an input signal (status signal  118 ) from voltage detector  110  indicating whether energy storage element  108  is sufficiently charged to actuate solenoid valve  502  (e.g., has a voltage of at least 4.5 volts, etc.) or is in need of charging. If the energy level of energy storage  108  is below the preset baseline voltage stored within CPU  240 , CPU  240  provides a signal from output  250  to charging circuit  106  indicating that charging circuit  106  should be activated for charging energy storage element  108 . Energy storage element  108  should be charged an amount sufficient to provide for multiple actuations of solenoid valve  502 . While charging circuit  106  is charging energy storage element  108 , CPU  240  sends signal from output  252  to activate indicator  112  to provide for a visual display that energy storage element  108  is being charged. 
     Once energy storage element  108  is sufficiently charged (registers a voltage greater than approximately 4.5 volts), and solenoid valve  502  is placed in the closed position, detection system  200  establishes a baseline infrared light level for the sensing region that will stored in CPU  240  and which will be compared to later obtained signals to determine if an object is within the sensing region. The baseline infrared light level of the sensing region is established by taking a sensing sample (i.e., comparing the background level of infrared light in the sensing region with the reflected level of infrared light in the sensing region) or a number of sensing samples which is then stored in CPU  240 . According to a particularly preferred embodiment, CPU  240  is powered approximately every 0.25 seconds to check the charge on energy storage element  108  and the level of infrared light in the sensing region and adjust the baseline value accordingly. 
     CPU  240  then enters a status referred to as a sensing cycle. During the sensing cycle, CPU  240  checks the charge of energy storage element  108  and depending upon the charge turns charging circuit  106  on or off. CPU  240  also checks the duration of time it has been since that last activation of solenoid valve  502  to adjust the time interval between sample periods accordingly. According to a particularly preferred embodiment, if solenoid valve  502  has been activated within 30 minutes, a sample of the sensing region will be taken every 0.25 seconds. However, if solenoid valve  502  has not been activated for a period greater than 30 minutes, CPU  240  will take a sample of the sensing region approximately every second in an effort to reduce power consumption. According to various alternative embodiments, CPU  240  may be programmed in a variety of ways in order to minimize power consumption when fixtures  14  have not been in use for extended periods of time. 
     CPU  240  then detects whether the level of infrared light in the sensing region has changed relative to the baseline value that is stored in CPU  240 . Once the level of infrared light in the sensing region changes by a predetermined amount (i.e., an indication that an object is within the sensing region), CPU  240  sends the appropriate output signal (either a signal from output  248  to open solenoid valve  502  or a signal from output  246  to close solenoid valve  502 ). 
     During one sensing cycle, CPU  240  sends a signal from output  242  to first monostable  262 . Upon receiving a signal from output  242  of CPU  240 , first monostable  262  starts a timing period. According to an exemplary embodiment, the start of the timing period closes a first switch of sample and hold circuit  210  (a switch between photodiode amplifier  234  and a first capacitor of sample and hold circuit  210 ). Once the first switch is closed, photodiode amplifier  234  provides an output voltage representative of the background level of infrared light in the sensing region to the first capacitor of sample and hold circuit  210 . At this point, LED  226  of transmitter  220  is not emitting a pulse of infrared light and therefore the only infrared light being detected and captured by receiver  230  is from the ambient light or other sensing signals in the sensing region. 
     First monostable  262  latches the background infrared level when first output  268  from first monostable  262  goes low. When first output  268  goes low, second output  270  from first monostable  262  goes high which triggers second monostable  264 . Upon activation, second monostable  264  provides a signal from output  274  which activates transmitter  220  and closes a second switch of sample and hold circuit  210  (a switch between photodiode amplifier  234  and a first capacitor of sample and hold circuit  210 ) to store the output voltage coming out of photodiode amplifier  234  (i.e. the output voltage represents the background level of infrared light). The second switch is held closed for a time interval sufficient to provide a control pulse to transmitter  220 . According to an exemplary embodiment, the second switch is held closed for a period of approximately 1.5 μs. At the same time, LED  226  of transmitter  220  emits pulses of infrared light into the sensing region. After approximately 1.5 μs, the second switch of sample and hold circuit  210  is opened and LED  226  is turned off. Advantageously, the sample period is therefore accomplished in a relatively short period (i.e. approximately 1.5 s). 
     There are two outputs from sample and hold circuit  210  (first output  211  and second output  214 ). First output  211  outputs the voltage stored in the first capacitor representative of the background level of infrared light (i.e., the level of infrared light in the sensory region when transmitter is not activated). Second output  214  outputs the voltage stored in the second capacitor representative of the background level of infrared light plus the level of infrared light while LED  226  was emitting pulses of infrared light. First output  211  and second output  214  are buffered through their respective buffers  212 ,  215  and subsequently fed into difference amplifier  213 . Out of difference amplifier  213 , a voltage representing only the reflected level of infrared light that was measured is provided. That value is fed into input  245  of CPU  240  for comparison with the baseline value stored therein. The value is held long enough by CPU  240  so that CPU  240  can measure the voltage (compare the reflected level of infrared light with the baseline value). According to an preferred embodiment, CPU  240  takes approximately 19 s to determine whether the reflected level of infrared light is higher than the established baseline value and whether a signal should be sent to fixture actuation system  500 . 
     In comparing the reflected level of infrared light with the baseline value, CPU  240  is programmed to recognize a slight increase in the infrared level as only a drift which can be used to adjust the baseline level. If a large increase in reflected infrared light is detected (e.g. when an object is within the sensing region), CPU  240  sends a signal from output  248  to fixture actuation system  500  to activate solenoid valve  502 . 
     The acquisition of the reflected level of infrared light takes about 1 millisecond (ms). After that period CPU  240  is turned off until the next cycle. According to a preferred embodiment, CPU  240  is turned off for approximately 0.25 seconds. As a result, CPU  240  is on for approximately 1 millisecond (ms) and is off for 250 ms. This is possible because of the shorten sample period for measuring the sensing region (e.g. 1.5 s). The remainder of the time is due to the power up time of the other components (e.g., photodiode amplifier takes about 100 μs to get a stable output value). Advantageously, control system  50  is conserving power during the 250 ms sleep period. If LED  226  remains on for a longer sample period (e.g., a sample period of 9 μs or greater), LED  226  will undesirably consume more power. 
     To activate solenoid valve  502 , CPU  240  sends a signal from output  248  to H-Bridge  504  indicating that solenoid should be moved to the open position. H-bridge  504  further receives fixture supply voltage  116  from energy storage element  108  of power supply system  100  for providing the necessary electrical energy to move solenoid valve  502 . H-bridge  504  flips the polarity of current coming from energy storage element  108  to open solenoid valve  502 . According to an exemplary embodiment, solenoid valve  502  will remain open until the “closed valve” signal is sent by CPU  240  (when the level of infrared light measured in the sensing region indicate that a user is no longer present). Control system  50  may optionally include a timer configured to send a signal to H-Bridge  504  indicating that solenoid valve  502  should be moved to the closed position after an established period of time, even if the “closed valve” signal is not sent by CPU  240 . 
       FIGS. 2 through 7 ,  10 , and  16  through  18  show photovoltaic system  600  and components thereof according to exemplary embodiments. Photovoltaic system  600  capable of converting ambient light energy into electrical energy that can be used to power a fixtures  14 , and/or a control system coupled to fixtures  14  (such as control system  50 ). Photovoltaic system  600  generally includes one or more photovoltaic cells  602  configured to convert ambient light energy into electrical energy and a power management system  650  providing for an efficient use of the electrical energy generated by photovoltaic cells  602 .  FIG. 16  shows photovoltaic system  600  is as power source  102  of power supply system  100  of control system  50 . 
     Referring particularly to  FIGS. 2 through 7 , photovoltaic system  600  includes one or more photovoltaic cells  602  (e.g., panels, elements, etc.), shown as an array of photovoltaic cells  602 , that are capable of converting energy from ambient light into electrical energy. Depending on the particular location of lavatory system  10 , ambient light may include artificial light (e.g., fluorescent, incandescent, halogen, etc.), natural light (sunlight), or a combination of artificial and ambient light. Preferably, photovoltaic cells  602  are capable of converting varying wavelengths of light into electrical energy (e.g., artificial light and natural light), but alternatively may be selected for being able to convert particular wavelengths of light into electrical energy. Photovoltaic system  600  represents an alternative power source to an AC power line. Unlike an energy storage element (e.g., a battery), photovoltaic system has a relatively infinite life so long as there is sufficient intensity of ambient light. 
     Photovoltaic cells  602  are coupled to lavatory system  10  at a position (e.g., location, orientation, etc.) that exposes photovoltaic cells  602  to ambient light, and preferably, at a position that maximizes their exposure to ambient light. Photovoltaic cells  602  may be supported by, mounted to, contained within, and/or integrally formed with a portion of lavatory system  10 . Photovoltaic cells  602  may be provided at a variety of positions including, but not limited to, support structure  12 , fixtures  14 , deck  17 , and/or basin  18 . According to various alternative embodiments, photovoltaic cells  602  may be positioned at a distance away from lavatory system  10 . For example, photovoltaic cells  602  may be provided on a wall, partition, a mirror, etc. and electrically coupled to fixtures  14  and/or control system  50  via a suitable wiring configuration. 
     According to a preferred embodiment, photovoltaic cells  602  are coupled to a relatively flat surface of lavatory system  10  (e.g., shelf  20 , etc.) that is likely to be laterally incident with the ambient light (i.e., perpendicular with the ambient light), but alternatively, may be positioned in any of a variety of positions, angles, and/or orientations depending on the application. According to a further alternative embodiment, photovoltaic cells  602  may be coupled to a curved surface such as a basin  18 , and/or a curved ledge or platform. 
     The configuration of lavatory system  10  (such as size and shape) will likely dictate the locations at which photovoltaic cells  602  will be positioned.  FIG. 2  shows photovoltaic cells  602  coupled to lavatory system  10  at a raised (e.g., elevated, heightened, offset, etc.) position relative to the other components of lavatory system  10 . Photovoltaic cells  602  are shown coupled to shelf  20  of support structure  12  which is positioned above fixtures  14 . Shelf  20  is an elevated surface that is not likely to have a relatively permanent obstruction (e.g., fixture, support structure, etc.) positioned between its top surface and the ambient light source which may limit the exposure of photovoltaic cell  602  to the ambient light source. 
       FIG. 3  is a top view of lavatory system  10  showing photovoltaic cells  602  coupled to shelf  20 . Photovoltaic cells  602  are shown as being divided into three groups or segments of photovoltaic cells, but alternatively, may be provided as one continuous segment of photovoltaic cells or as individual photovoltaic cells. The number of photovoltaic cells  602  coupled to lavatory system  10  may vary depending on a number of factors including, but not limited, the available surface area of lavatory system  10  capable of accepting photovoltaic cells  602 , the power requirements of the control system and/or fixtures  14 , the output and efficiency of photovoltaic cells  602 , and/or aesthetic considerations. 
     According to an exemplary embodiment, it is desirable to maximize the number of photovoltaic cells  602  used with lavatory system  10  as is reasonably practical. For example, still referring to  FIG. 3 , photovoltaic cells  602  cover a substantial portion of the surface area of shelf  20 . According to various alternative embodiments, the number of photovoltaic cells  602  used may be limited rather than maximized. The use of commercially available photovoltaic cells  602  (e.g., photovoltaic cells have an established size) may constrain the number of photovoltaic cells coupled to lavatory system  10 . 
       FIGS. 4 and 5  show a method of coupling photovoltaic cells  602  to lavatory system  10  according to an exemplary embodiment. Referring particularly to  FIG. 4 , shelf  20  is shown having an aperture (e.g., cavity, opening, channel, depression, etc.), shown as a recess  142 , configured to receive photovoltaic cells  602 . Shelf  20  may be formed (e.g., molded, cast, manipulated, etc.) with recess  142 , or alternatively, material may be removed (e.g., milled, cut, drilled, shaved, etc.) from shelf  20  to provided recess  142 . Preferably, recess  142  has a depth sufficient so that when photovoltaic cells  602  are positioned therein, the tops of photovoltaic cells  602  do not outwardly extend above the top surface of shelf  20 . Such a configuration may allow for a relatively continuous surface once photovoltaic cells  602  a covered by a suitable coating. 
     Photovoltaic cells  602  are shown to include wires  605  used to electrically couple photovoltaic cells  602  to fixtures  14  and/or a control system for controlling fixtures  14  or some other component of lavatory system  10 . Preferably recess  142  includes an opening for allowing wires  605  to be routed to the desired location while concealing wires  605  from the view of a user. 
       FIG. 5  shows photovoltaic cells  602  as being coupled to shelf  20  via a relatively clear (e.g., transparent, translucent, etc.) sealer or coating, shown as a resin  603 . The coating may include, but is not limited to, an epoxy, a polyester resin, or any other suitable material that can be added to recess  142  for coupling photovoltaic cells  602  and will allow for sufficient levels of ambient light to pass through to photovoltaic cells  602 . In such a configuration, photovoltaic cells  602  are substantially integrally formed with shelf  20 . Shelf  20  may in turn be permanently coupled to upper portion  16  of support structure  12 , or alternatively, may be detachably coupled so that shelf  20  can be readily removed in the in event that photovoltaic cells  602  need to be replaced and/or repaired. 
     According to an exemplary embodiment, resin  603  is added to recess  142  to couple photovoltaic cells to shelf  20 . Preferably, resin  603  is disposed on the tops of photovoltaic cells  602  to provide protection. According to a particularly preferred embodiment, a first layer of resin  603  is disposed between photovoltaic cells  602  and shelf  20  and a second layer of resin  603  is disposed on top of photovoltaic cells. Such a configuration may help maintain the position and/or the integrity of photovoltaic cells  602  as resin  603  is added (e.g., poured, etc.) over the tops of photovoltaic cells  602 . After resin  603  is allowed to harden, resin  603  is preferably finished so that resin  603  is substantially even in height with the top surface of shelf  20 . According to various alternative embodiments, resin  603  may only be applied over the tops of, along the sides of, and/or beneath photovoltaic cells  602 . 
     According to an alternative embodiment, photovoltaic cells  602  may be mounted to shelf  20 . Photovoltaic cells  602  may be directly mounted to shelf  20 , or alternatively, may be indirectly mounted to shelf  20 . Photovoltaic cells  602  may be mounted to shelf  20  using any of a variety of suitable methods including, but not limited to, mechanical fasteners (e.g., clips, screws, staples, brackets, collars, cover plates, etc.), adhesives, and/or any suitable welding process. The mounting of photovoltaic cells  602  may be intended to be relatively permanent, or alternatively, may be intended to be removable so that photovoltaic cells  602  readily removed and replaced (or repaired) if damaged. 
     To protect photovoltaic cells  602  from contaminants and/or manipulation (e.g., vandalism), a relatively clear member may be disposed over photovoltaic cells  602 . For example, a relatively clear (e.g., transparent, translucent, etc.) glass member or plastic member (e.g., acrylic, etc.) may be disposed over photovoltaic cells  602 . Such a member may also be configured to at least partially secure photovoltaic cells  602  to shelf  20 . The member may be a relatively rigid member, or alternatively may be a relatively flexible member such as a flexible film, or some other suitable material. 
       FIGS. 6 and 7  show a method of coupling photovoltaic cells  602  to lavatory system  10  according to another exemplary embodiment. Lavatory system  10  is shown as being configured to support one or more photovoltaic cell packages or units comprising a receptacle (shown as a relatively shallow pan or tray  604 ). Tray  604  is sized and dimensioned to receive one or more photovoltaic cells  602 . Photovoltaic cells  602  are coupled to tray  604 , which is in turn coupled to lavatory system  10 . 
     Trays  604  may be permanently coupled to lavatory system  10  or detachably coupled to lavatory system  10 . The use of photovoltaic cell units may provide for modularity in lavatory system  10 , and allow photovoltaic cells  602  to be readily installed, removed, and/or interchanged. Such a configuration may allow photovoltaic cells  602  to be efficiently removed in the event that photovoltaic cells  602  are to be repaired or replaced. Preferably, the photovoltaic cell units are coupled to lavatory system  10  from an area generally not accessible to a user (e.g., from the bottom of shelf  20 ) in an attempt to protect from (or minimize the effect of) tampering and/or vandalism and/or other known harm to photovoltaic cells  602 . 
     Tray  604  is shown as being coupled to shelf  20  of support structure  12  and received within recess  142 . Referring to  FIG. 7 , photovoltaic cells  602  are coupled to tray  604  using resin  603 . According to a preferred embodiment, photovoltaic cells  602  are inserted in tray  604  and resin  603  is disposed over the tops of photovoltaic cells  602  and allowed to harden. The resultant photovoltaic cell units may then be coupled to shelf  20 . 
       FIGS. 10 and 16  show a block diagram of control system  50  incorporating photovoltaic system  600  as power source  102 . It should be noted that photovoltaic system  600  not limited in application to control system  50  or other control systems designed to provide for “hands free” operation of a fixture. According to various alternative embodiments, photovoltaic system  600  may be used in combination with other forms of control systems and/or fixtures requiring or using electric energy in order to operate (or assist in operation). For example, photovoltaic system  600  may be configured to provide electrical energy to a control system coupled to a fixture having a user interface that is electrically actuated (e.g., an electric push-button, a touch sensor, etc.). 
       FIG. 17  shows a detailed block diagram of power management system  650  and components thereof according to an exemplary embodiment. Power management system  650  advantageously provides for an efficient use of the electrical energy generated by photovoltaic cells  602 . Power management system  650  is shown as generally including an energy storage element  660  configured to receive and store electrical energy generated by photovoltaic cells  602 , a detector  670  configured to measure the level (intensity) of ambient light, a switch  680  configured to disconnect energy storage element  660  from control system  50  if the level of ambient light drops below a predetermined value, and a voltage regulator  690  for adjusting the voltage being outputted to control system  50 . 
     According to an exemplary embodiment, energy storage element  660  includes one or more capacitors suitable for receiving a electric charge from photovoltaic cells  602  and supplying an output voltage to control system  50 . According to a preferred embodiment, energy storage element  660  includes a plurality of capacitors arranged in series to provide the desired capacitance of approximately 3.3 farads (F). According to a particularly preferred embodiment, energy storage element  660  includes a first capacitor, a second capacitor, and a third capacitor. First capacitor, a second capacitor, and a third capacitor are super capacitors having a capacitance of approximately 10 F each or a combined capacitance of approximately 3.3 F. According to an alternative embodiment, other numbers and/or types of capacitors may be used and such capacitors may be arranged in series and/or in parallel. 
     Energy storage element  660  may be fully charged or partially charged by photovoltaic cells  602 . The rate at which energy storage element  660  is charged depends at least partially on the intensity of the ambient light and the effectiveness (e.g., number, size, efficiency, etc.) of photovoltaic cells  602 . During an initial setup (e.g., anytime energy storage element  660  is fully discharged), the time required to charge energy storage element  660  to a level sufficient to operate the components of control system  50  may be relatively long. The charging time during the initial setup can be reduced by adding a supplemental power source (e.g., a battery, etc.) to charge energy storage element  660 . The supplemental power source provides a “jump-start” for energy storage element  660 , and may significantly reduce the charging time. Preferably, any supplemental power source is removed once energy storage element  660  is sufficiently charged, but alternatively, may remain coupled to the system but electrically disconnected from energy storage element  660 . 
     A fully charged energy storage element  660  is capable of providing a sufficient amount of electrical energy to power control system  50  for the selective operation of fixtures  14 . According to an exemplary embodiment, energy storage element  660  is capable of providing a sufficient amount electrical energy to allow for more than one activation of fixtures  14  before energy storage element  660  needs to be recharged. According to a preferred embodiment, energy storage element  660  can retain or hold a sufficient amount of electrical energy to provide approximately 70 activations of fixtures  14  before needing to be recharged. As can be appreciated, in a typical application (e.g., an application wherein photovoltaic cells  602  are exposed to ambient light while lavatory system  10  is being used), photovoltaic cells  602  will continue to charge energy storage element  660  as electrical energy is provided for the activation of fixtures  14 . 
     Control system  50  constitutes a load on energy storage element  660  that when electrically coupled thereto diminishes the electrical energy stored in energy storage element  660 . Disconnecting energy storage element  660  from such a load will help maintain the charge of energy storage element  660 . To determine whether power should be conserved by disconnecting control system  50  from energy storage element  660 , power management system  650  further includes voltage detector  670 . Voltage detector  670  includes an input  672  electrically coupled to an output from photovoltaic cells  602 . Voltage detector  670  also includes an output  674  electrically coupled to switch  680 . 
     An output voltage is provided by photovoltaic cells  602 . The magnitude of the output voltage may be based upon the intensity of the ambient light and the efficiency of photovoltaic cells  602 . Voltage detector  670  detects whether photovoltaic cells  602  are being exposed to a level of ambient light sufficient to meet the power demands of control system  50 . According to an exemplary embodiment, a reference voltage value (a baseline value) representative of the sufficient level of ambient light is maintained by voltage detector  670 . Such a reference value may be changed depending on the power requirements of control system  50 . 
     According to an exemplary embodiment, if photovoltaic cells  602  are not being exposed to a sufficient level of ambient light, the assumption is that lavatory system  10  is not in use (e.g., the lights have been turned down and/or off) and that control system  50  does not need to be powered. In such a situation, control system  50  is disconnected from power management system  650  in an effort to conserve electrical energy. According to a preferred embodiment, voltage detector  670  measures the output voltage of photovoltaic cells  602  (received at input  672 ) and compares the output voltage with the reference voltage value. If the output voltage level is below the reference voltage level, voltage detector  670  will send an output signal (at output  674 ) to switch  680  indicating that control system  50  should be electrically disconnected from power management system  650 . According to various alternative embodiments, voltage detector  670  may be replaced with any detector suitable for detecting the intensity of the ambient light at photovoltaic cells  602  including, but not limited to, a photodetector configured to monitor the ambient light and send a corresponding signal to switch  680 . 
     Preferably, energy storage element  660  is capable of holding a charge with minimal leakage when disconnected from the load (control system  50 ). Providing energy storage element  660  that is capable of maintaining a charge with minimal leakage, may allow energy storage element  660  to meet the electrical power requirements of control system  50  after photovoltaic cells  602  have not been exposed to ambient light for an extended period of time (e.g., a weekend, etc.). This will eliminate the need to recharge energy storage element  660  (e.g., by a supplemental power source and/or by photovoltaic cells  602 , etc.), or at least reduce the time required to recharge energy storage element  602 , when the ambient light returns and a user seeks to use fixtures  14  of lavatory system  10 . When voltage detector  670  measures a voltage at or above the predetermined baseline voltage, switch  680  reconnects power management system  650  to control system  50 . 
     Power management system  650  is further shown as including voltage regulator  690  adapted for receiving a first voltage from photovoltaic cells  602  and providing a second voltage to control system  50 . According to an exemplary embodiment, voltage regulator  690  is capable of providing a relatively stable operating voltage to control system  50 . According to an exemplary embodiment, voltage regulator  690  is shown schematically as a dc-to-dc converter. According to a preferred embodiment, the voltage entering the dc-to-dc converter may range between approximately 1.5 volts and 7.5 volts, while the voltage exiting the dc-to-dc converter is approximately 5 volts. As can be appreciated, the input and output voltages may vary in alternative embodiments. 
     It is important to note that the construction and arrangement of the elements of the lavatory system, including the fixtures, the control system, and/or the photovoltaic system, as shown in the preferred and other exemplary embodiments are illustrative only. Although only a few embodiments of the present inventions have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, and proportions of the various elements, values of parameters, mounting arrangements, etc.) without materially departing from the novel teachings and advantages of the subject matter recited herein. For example. For example, the circuit diagrams provided are schematic only, and the values for the individual components (e.g., the ratings for the resistors, capacitors, etc.) may vary according to alternative embodiments. Further, while the description herein may suggest that a pulse generator is used to control pulsing of the transmitter, such control may be accomplished by other means (e.g., software, programming, computations, algorithms, etc.). Even further, while the inventions described herein are described with reference to use washing stations, the inventions may be used with any of a variety of different applications wherein a control system of the type disclosed herein would be beneficial. Further, the position of elements may be reversed or otherwise varied (e.g., the circuit diagram may be modified or may be incorporated in other circuits), and the nature or number of discrete elements or positions may be altered or varied. It should further be noted that the scope of the inventions include all software conventionally known or suitable for use with proximity sensors. For example, the control system may be programmed with failure modes for closing the valve if left open for an extended period. Further, the control system may be programmed to provided extended sleep periods when the fixture has not been used for a set time. The control system may also be programmed to require two positive reads before the valve is opened. 
     The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the inventions as expressed in the appended claims.