Patent Publication Number: US-2021161754-A1

Title: Oral irrigator with reservoir valve

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of U.S. patent application Ser. No. 15/588,538, entitled “Oral Irrigator with Variable Output Fluid Characteristics,” filed on May 5, 2017, which is a continuation application of U.S. patent application Ser. No. 13/831,401, entitled “Oral Irrigator with Massage Mode,” filed on Mar. 14, 2013, now U.S. Pat. No. 9,642,677, which are hereby incorporated by reference herein in their entireties. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to health and personal hygiene equipment and methods of controlling such equipment. More particularly, the present disclosure relates to oral irrigators and methods of controlling such equipment. 
     BACKGROUND 
     Oral irrigators typically are used to clean a user&#39;s teeth and gums by discharging a pressurized fluid stream into a user&#39;s oral cavity. The fluid impacts the teeth and gums to remove debris. Often, some users may prefer one pressure level whereas others may prefer another pressure. However, typically, the pressure level may be determined by characteristics of the pump and motor and may not be variable between users. For example, certain flow characteristics, such as pressure, are determined by a mechanical valve, cavity or fluid passage size, or the like, which may not be altered based on particular user preferences and may be complicated to manufacture. 
     SUMMARY 
     One example may take the form of a handheld oral irrigator general includes an irrigating device, such as an oral irrigator or a nasal irrigator. The irrigating device includes a pump and a motor connected to the pump and configured to selectively drive the pump. Additionally, the irrigating device includes a massage module in communication with the motor. During a normal mode, the pump has a first pulse rate and during a massage mode, the massage module provides a massage control signal to the motor, causing the pump to have a second pulse rate. 
     Another example may take the form of a method for varying a pulse rate for an oral cleaning device. The method includes activating a motor connected to pump; determining by a processing element whether a massage mode should be activated; if the massage mode is activated, providing a massage signal to the motor, causing a massage pulse rate output by the pump; and if the massage mode is not activated, providing a normal signal to the motor, causing a normal pulse rate output by the pump. 
     Yet another example may take the form of an oral irrigator. The oral irrigator includes a reservoir defining a fluid cavity, a pump in fluid communication with the fluid cavity, and a motor connected to the pump and configured to selectively activate the pump. The oral irrigator may also include a handle in fluid communication with the pump and a signal generator in communication with the motor and configured to selectively vary a control signal provided to the motor to vary one or more output characteristics of the motor. 
     In another example, an oral irrigator including a reservoir, a tip in fluid communication with the reservoir, a pump in fluid communication with the tip and the reservoir, where the motor drives the pump is disclosed. The oral irrigator also includes a control module electrically coupled to the motor to vary an output of the motor. During a normal mode, the control module drives the motor to output a normal pulse rate, a normal flow rate, and a normal fluid pressure as the fluid exits the lip and during a massage mode, the control module drives the motor to output a massage pulse rate, a massage flow rate, and a massage fluid pressure as the fluid exits the tip. The massage pulse rate is lower than the normal pulse rate, the massage fluid pressure is lower than the normal fluid pressure, and the massage fluid pressure is lower than the normal fluid pressure. 
     In yet another example, an oral irrigation device includes a fluid reservoir; a reciprocating pump in fluid communication with the fluid reservoir; a tip in fluid communication with the pump; a motor operably connected to the pump, wherein the motor drives the pump to pump fluid from the fluid reservoir to the tip; a mechanically adjustable valve that varies one or more fluid path characteristics of a flow path between the reservoir and the tip to change an outlet fluid pressure of fluid exiting the tip; and a processing element in electrical communication with the motor. The processing element varies performs the following operations: responsive to receiving a first user input, the processing element varies a voltage applied to the motor to vary a fluid output pressure of the fluid exiting the tip; and responsive to receiving a second user input, the processing element varies a frequency applied to the motor to vary a fluid pulse rate of the fluid exiting the tip. 
     In another example, an oral irrigator includes a base, a reservoir supported by the base and including a bottom wall and a port defined in the bottom wall, and a valve received in the port. The valve is movable between a first position in which the port is open to allow fluid flow from the reservoir to the base and a second position in which the port is closed by the valve. The valve includes a body, a cap extending from a first end of the body, a flange extending from a second end of the body opposite the first end, a sealing member positioned around the body adjacent the cap, and a spring positioned around the body adjacent the flange. 
     While multiple examples are disclosed, still other examples of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative examples of the invention. As will be realized, the invention is capable of modifications in various aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a front perspective view of an oral irrigator including a massage module. 
         FIG. 1B  is a rear perspective view of the oral irrigator of  FIG. 1A . 
         FIG. 2  is a front perspective view of a second example of an oral irrigator including a massage mode. 
         FIG. 3A  is a cross-section view of the oral irrigator taken along line  3 A- 3 A in  FIG. 1B . 
         FIG. 3B  is a cross-section view of the oral irrigator taken along line  3 B- 3 B in  FIG. 1A . 
         FIG. 4A  is a front perspective view of the oral irrigator with select components hidden for clarity. 
         FIG. 4B  is a rear perspective view of the oral irrigator with select components hidden for clarity. 
         FIG. 5  is a simplified block diagram of the electrical components of the oral irrigator. 
         FIG. 6  is a simplified circuit diagram of the massage module. 
         FIG. 7A  is a first example of an illustrative circuit schematic for an implementation of the electrical components of the oral irrigator. 
         FIG. 7B  is a second example of an illustrative circuit schematic for an implementation of the electrical components of the oral irrigator. 
         FIG. 7C  is a third example of an illustrative circuit schematic for an implementation of the electrical components of the oral irrigator. 
         FIG. 7D  is an example of a switch control board for the oral irrigator. 
         FIG. 8A  is diagram of a first control signal produced by the massage module. 
         FIG. 8B  is a diagram of a second control signal produced by the massage module. 
         FIG. 8C  is a diagram of a third control signal produced by the massage module. 
         FIG. 9A  is a chart illustrating an example of pressure ranges for the oral irrigator during clean mode. 
         FIG. 9B  is a chart illustrating an example of pressure ranges for the oral irrigator during massage mode. 
         FIG. 10  is a flow chart illustrating a method for operating the oral irrigator including the massage module. 
         FIG. 11  is a flow chart illustrating a method for dynamically adjusting the pressure and pulse rate of the oral irrigator using the massage module. 
     
    
    
     DETAILED DESCRIPTION 
     Some examples of the present disclosure include an irrigating device, such as an oral irrigator, having a massage module. The massage module may be configured to vary one or more characteristics of a fluid stream to create a fluid flow that may massage a user&#39;s gums, as well as enhance user&#39;s comfort as the user cleans his or her teeth or gums. The oral irrigator may include a motor and a pump connected to and controlled by the motor. The pump is fluidly connected to a fluid supply and pumps fluid from the supply to an outlet (such as a tip). The massage module may also be in communication with the motor and may provide one or more control signals to the motor to vary one or more characteristics of the motor, such as speed, power, or torque. Because the motor is connected to the pump, as the massage module varies the speed or other characteristic of the motor, the output characteristics of the pump may be correspondingly varied. The output characteristics of the pump may be varied based on a fluid flow that may “massage” a user&#39;s gums, such as a pulsed output where the fluid pulses (the flow intermittently turns on an off). In another example, the massage module may vary the outlet fluid pressure of the oral irrigator during massage mode, e.g., may reduce the outlet pressure as compared to clean mode. In this example, the fluid pulse rate may remain substantially the same in both clean mode and massage mode or may also be varied along with the pressure. 
     In some examples, the oral irrigator may include a cleaning or normal mode and a massage mode. During the cleaning mode, the oral irrigator may include a relatively steady fluid flow or may include a fluid flow having a slight pulse (e.g., due to a mechanical characteristics of the pump). During the massage mode, the massage module may vary the fluid pulsing length and/or pressure. For example, the massage module may vary a control signal to selectively vary the power level provided the motor. In a specific implementation, the power may be selectively activated and deactivated, which may cause the motor to produce intermittent motion resulting in varying the output of the pump. The pump may be selectively activated to create a pulsating fluid flow through the oral irrigator outlet (e.g., the tip). 
     In one example, the pulses created by the massage module may be longer fluid pulse or breaks in the fluid stream as compared to the normal operation. The increase in pulse length causes the fluid stream to massage a user&#39;s gums, enhancing blood flow and providing an enjoyable experience to the user. This is because the pulses may be timed with recovery the gum tissues (e.g., timed to allow blood to flow back into the tissue between each fluid pulse), and provides therapeutic benefits to the gums. 
     The massage mode may vary one or more characteristics of the control signal based on user input. For example, the user may select the massage mode and may then vary the frequency, magnitude, or shape of the control signal, such as changing the shape of a voltage waveform or its frequency. In other examples, the massage mode may apply a predetermined signal to the motor. For example, a control signal may be determined for the massage mode and when the massage mode is activated by the user, the stored signal may be applied. In these examples, the oral irrigator may include a plurality of control signals that may correlate to different massage modes. In yet other examples, the oral irrigator may include stored signals that may be selected by a user for a predetermined pulsing effect, as well as may vary one or more signals to allow the user to dynamically variable the pulsing effect. 
     In addition to providing a massage mode, the massage module or another processing element of the oral irrigator may vary one or more output characteristics of the oral irrigator to provide feedback to a user. As a first example, the massage mode may be activated automatically one or more times during normal mode to indicate to a user to move to a different tooth or portion of the mount. As a second example, the massage mode may be activated after a predetermined time period in order to alert the user that a cleaning time (which may be set by the user or be preselected) has expired. As a third example, the massage mode may be activated automatically every time period, e.g., every 30 seconds the massage mode may be activated to provide a massaging feel interspersed with cleaning. 
     In other examples, the massage module may be used with other irrigating devices. For example, the massage mode may be implemented in a nasal irrigator and may vary the fluid flow rate and pressure to massage the user&#39;s nasal tissues. In these examples, the pulse rate and control signal may be varied as compared to the oral irrigator, but may still provide a massaging effect. 
     In yet other examples, the massage module may be used with other oral instruments to provide a massaging effect and/or to enhance cleaning. For example, the massage module may be incorporated into an electrically driven toothbrush. In this example, the massage module may vary the motor speed or power to vary vibrations or bristle movement. 
     With reference now to the figures, the oral irrigator will be discussed in more detail.  FIG. 1A  is a front perspective view of an oral irrigator including a massage mode.  FIG. 1B  is a  FIG. 2  is a rear perspective view of the oral irrigator of  FIG. 1A . With reference to  FIGS. 1A and 1B , the oral irrigator  100  may include a base  102 , a reservoir  104 , and a handle  108 . The base  102  may provide support for the reservoir  104  and the handle  108 , as well as house many of the drive and power assembly components of the oral irrigator  100 . For example, the base  102  may house a pump, control circuitry, and/or motor, which will be discussed in more detail below. 
     The base  102  may include a bottom support  128  and a cover  130 . The bottom support  128  may provide support for one or more of the internal components of the oral irrigator  100  and the cover  102  may cover those components to conceal them, as well as provide protection for those components. The base  102  may include a plurality of feet  132   a ,  132   b ,  132   c , and  132   d  to support the base  102  on a surface, such as a countertop or the like. 
     The base  102  may also include a clamp  134  or other structure to releasably support the handle  108 . In some examples, the clamp  134  may be a C-clamp; however, other attachment mechanisms are envisioned. The base  102  may also include a hose cavity  136  or hose box that may receive and support the hose  118  in a collapsed position. For example, the hose cavity  136  may include one or more arms on which the hose  118  may be wrapped. The hose cavity  136  may be recessed into the cover  130 , may be flush with the cover, or may extend outwards from the cover. 
     The oral irrigator  100  illustrated in  FIGS. 1A and 1B  is a countertop irrigator. However, in some examples, the oral irrigator  100  may be a handheld irrigator.  FIG. 2  is a front perspective view of a second example of an oral irrigator. With reference to  FIG. 2 , in examples where the oral irrigator  100  is a handheld unit, the reservoir  104  and handle  106  may be connected together. The reservoir  104  may include a removable cavity that may refilled by a user and then reattached to the handle  106 . Additionally, in these examples, the internal components of the irrigator  100 , such as the motor, pump, and control circuitry, may be included within the handle  106  rather than a base unit. The description of the oral irrigation described below is generally directed to the oral irrigator illustrated in  FIGS. 1A and 1B ; however, it should be noted that the description is equally applicable to the oral irrigator  100  shown in  FIG. 2 , with the exception that the internal components of the base are included in the handle  106 . 
       FIGS. 3A and 3B  are cross-section views of the oral irrigator taken along lines  3 A- 3 A and  3 B- 3 B, respectively, in  FIGS. 1A and 1B . With reference to  FIGS. 4A and 4B , the reservoir  104  defines a cavity  105  to hold liquid that may be expelled trough a tip  114  connected to the handle  108 . The reservoir  104  may include a lid  120  and may be removable from the base  102 . In some examples, the oral irrigator  102  may be a handheld or more compact and the reservoir  104  may be incorporated into the handle  108  (e.g., a container attachable to the handle  108 ). The reservoir  104  may be substantially any size or shape and may be modified as desired, for example, as shown in  FIG. 2 , the reservoir is included as a cavity attached to the handle. 
     With reference again to  FIGS. 1A and 1B , the handle  108  is movable relative to the base  102  and may be fluidly connected to the reservoir  104 . For example, a hose  118  may fluidly connect the reservoir  104  to the handle  108  and tip  114 . In examples where the reservoir  104  may be incorporated into the handle  108 , the hose  118  may be internal to the handle  108  or may be omitted (e.g., a fluid pathway may be defined through a housing of the handle rather than a tube). In some examples, the handle  108  may include a plurality of internal components, such as a check valves, bypass valves, pause valves, or the like. In these examples, the handle  108  may be used to vary one or more characteristics of the fluid flow output by the tip, separate from or in addition with the features for controlling the fluid output within the base. As mentioned above, although a number of components, such as the pump, reservoir, etc., are discussed herein as being incorporated into the base, in certain examples these components may be included with the handle. For example, as shown in  FIG. 2 , a handheld oral irrigator may include a portable reservoir attached to the handle with a pump internal the handle. Accordingly, the discussion of any particular example for the handle and base is meant as illustrative only. 
     The tip  114  may be selectively removable from the handle  108 . For example, an eject  126  button can selectively release the tip  144  from the handle  108 . The tip  114  defines a fluid pathway that is fluidly connected to the hose  118 . The tip  114  includes an outlet  122  from which fluid from the reservoir  104  may be expelled from the oral irrigator  100 . The tip  114  may generally be configured to be inserted into a user&#39;s mouth and may expel fluid against a user&#39;s teeth, gums, tongue, etc. In some examples, the outlet  122  portion of the tip  144  may be shaped as a nozzle or may include a nozzle or other attachment connected thereto. 
     The oral irrigator  100  may include a plurality of control actuators  110 ,  112 ,  113 ,  124  to control one or more characteristics or parameters of the oral irrigator  100 . For example, the control actuators  110 ,  112 ,  124  may activate/deactivate the oral irrigator  100 , may vary a flow rate, a fluid pressure, a setting (e.g., slow, medium fast), and/or may activate a particular mode, e.g., massage mode. The number of control actuators  110 ,  112 ,  113 ,  124 , as well as their structure, size, or shape may be varied as desired. For example, as shown in  FIGS. 1A and 1B , the two control actuators  110 ,  112  on the base  102  are illustrated as rotatable knob or buttons; however, in other examples, the control actuators  110 ,  112 ,  113  may be switches, sliders, or the like. 
     A first control actuator  110  may be configured to vary a fluid pressure of fluid as it exits the tip  114 . For example, the control actuator  110  may be connected to a valve that may selectively change the diameter or other fluid pathway characteristics of a fluid outlet or pathway between the reservoir  104  and the tip  114 . As the diameter is varies, such as due to a user turning the control actuator  110 , the outlet fluid pressure as fluid is expelled from the tip  114  may be selectively modified. As another example, the first control actuator  110  may activate a massage module to activate a massage mode for the oral irrigator  100 . 
     A second control actuator  112  on the base may be configured to selectively power the oral irrigator  100 . In other words, the second control actuator  112  may be a power button or knob to turn on the oral irrigator  100 . Additionally, in some examples, the second control actuator  112  may activate one or more settings. As an example, the second control actuator  112  may activate and deactivate the oral irrigator  100 , as well as select one or more settings, such as a massage mode, low pressure, high pressure, or the like. 
     A third control actuator  113  on the base may be configured to selectively activate massage mode. In some examples the third control actuator  113  may be positioned adjacent to the second control actuator  112  and may be a compressible button, rather than a knob. However, in other examples, the control actuator  113  may be a knob and may be located on the handle or other portions of the base  102 . 
     In some examples, a fourth control actuator  124  may be disposed on the handle  108 . The fourth control actuator  124  may selectively activate one or more settings or may act to pause the oral irrigator  100 . By placing the control actuator  124  on the handle  108 , the user may more easily change settings or pause the oral irrigator  100  while he or she is using the oral irrigator  100 . 
     The various control actuators  110 ,  112 ,  113 ,  124  may be configured as desired and may change one or more settings or parameters of the oral irrigator  100 . For example, any of the buttons  110 ,  112 ,  113 ,  124  may be configured to activate a massage mode for the oral irrigator  100 . 
     The oral irrigator  100  may also include a plurality of lights  117   a ,  117   b , which may be used to provide feedback to a user. For example, the lights  117   a ,  117   b  may illuminate, change color, or may pulse to indicate a current mode of the oral irrigator, a pressure level of the oral irrigator, or the like. In a specific example, a first light  117   a  is illuminated during normal mode and a second light  117   b  is illuminated during massage mode. See, for example,  FIG. 7D . 
     With reference to  FIG. 1B , the oral irrigator  100  may include a power cable  116  or port to receive a power cable. The power cable  116  may be configured to be received into an outlet or power source and may transfer power from a power source to the oral irrigator  100 . It should be noted that the type of power cable  116  might be varied based on the power source for the oral irrigator  100 . Alternatively, such as the oral irrigator shown in  FIG. 2 , the oral irrigator  100  may include an integrated power supply; such as one or more batteries, and in these cases the power cord  116  may be omitted or may be used to recharge the integrated power supply (rather than directly provide power to the oral irrigator  100 ). As will be discussed in more detail below, the power cord  116  may function to act as a power supply for the oral irrigator. 
     An illustrative example of the internal components of the oral irrigator  100  will now be discussed in further detail.  FIGS. 4A and 4B  are various perspective views of the oral irrigator  100  with select elements hidden for clarity. With reference to  FIGS. 4A-4B  the oral irrigator  100  may include a motor  142 , a gear box  144 , a pump  146 , and a chassis  140  supporting the motor  142 , gear box  144  and pump  146 . A valve assembly  156  including a valve  158  may fluidly connect the reservoir  104  to the pump  146  and a valve fitting  152  may fluidly connect the pump  146  to the hose  118  (and thus the tip  114  and handle  108 ). Additionally, a check valve  167  may be positioned between the valve assembly  156  and the valve fitting  152 . The check valve  167  may regulate fluid pressure of the oral irrigator  100 . The oral irrigator  100  may also include a control circuitry  164  having a signal generator  166  in electrical communication with the motor  142 . 
     With reference to  FIGS. 3A and 4A , the motor  142  may be substantially any type of motor that may drive movement or create mechanical work sufficient to drive a pump. For example, the motor  142  may be a direct current motor, where the speed of the motor  142  may be controlled by a signal, such as a voltage signal. Control of the motor  142  will be discussed in more detail below. 
     With reference to  FIGS. 3A and 4A , the motor  142  may include a drive shaft  143  (see  FIG. 3A ) that is connected to a gear shaft  147  and a drive gear  149 . The drive gear  149  is connected to a piston  145  or other moveable element within the pump  146 . The gear box  144  may cover the gear shaft  147 , the drive gear  149 , and other mechanical gears or linkage elements that may be used to connect the drive shaft  143  of the motor  144  to the pump  146 . The linkage and gear elements may be varied as desired and may depend on the orientation of the motor and the pump relative to one another, the size or speed of the motor, and the like. 
     The pump  146  may be substantially any type of component that may pump fluid from one location to another. For example, the pump  146  may be a piston driven pump that may selectively push fluid from the reservoir  104  into the hose  118 . However, many other pump types are envisioned. Some illustrate pump types include a diaphragm pump or a centrifugal pump. The pump  146  may include a pump body  169  and an inlet pump  165  received within the pump body  169 . The first control actuator  110  may be connected to the pump  146  and may be attached to a bypass valve or other control valve (not shown). As discussed briefly above, the first control actuator  110  may selectively vary the pressure of fluid output from the pump  146  and may do so by varying the diameter of a fluid channel between the pump  146  and the tip  114 . 
     With continued reference to  FIGS. 3A-4B , the valve assembly  156  may be connected to the pump  146  and received into a bottom of the reservoir. The valve assembly  156  may include a valve  158  and one or more sealing members  160 ,  162 , such as O-rings or sealing cups. The valve  158  may regulate fluid flow from the reservoir  104  into the pump  146 . Accordingly, the valve  158  is in fluid communication with the reservoir  104  and provides fluid from the reservoir  104  into the pump  146 . 
     The valve fitting  152  includes a fluid outlet  154  and fluidly connects the pump  146  to hose  118 . The valve fitting  152  may be connected to the hose  118  and provide a fluid pathway from the reservoir  104  to the handle  108 . 
     The oral irrigator  100  may also include one or more isolators  168 . The isolators  168  may connect the chassis  140  to the bottom support  128  of the base  102 . In some examples, the isolators  168  may absorb vibrations from the motor  142  and the pump  146 , to reduce the vibrations that may be transmitted to the bottom support  128  and/or feet  132   a ,  132   b ,  132   c ,  132   d . For example, the isolators  168  may be an elastomeric material or other material configured to absorb vibrations. 
     Additionally, in some examples, the oral irrigator  100  may include one or more feedback components. For example, the lights  117   a ,  117   b , which may be light emitting diodes (LEDs) can be used to provide feedback to the user. Continuing with this example, the lights  117   a ,  117   b  may be illuminated to indicate the mode of the oral irrigator (e.g., massage mode or normal mode), or may be illuminated to indicate a cleaning or activation time, or the like. 
     The control circuit  164  may control the motor  142  and other elements of the oral irrigator  100 .  FIG. 5  is a simplified block diagram of the oral irrigator  100  illustrating the electrical communication between select components. With reference to  FIGS. 3A and 5 , a power source  115  (which may be an outlet in communication via the power cable  116  or one or more batteries) may be in communication with a massage module  172 , the motor  142 , and optionally, one or more of the input buttons  110 ,  112 ,  124 . For example, the second control actuator  112  may be in communication with a switch  148  module that may be in communication with control circuitry  164  and/or power source  115  to selectively activate the motor  142 . 
     In some examples, the control circuitry  164  may provide a substrate that supports one or more components, as well as provides communication between those components. For example, the control circuit  164  may be a printed circuit board including one or more traces or connective lines that transmit signals between the massage module  172 , the motor  142 , and/or the power source  115 . 
     The massage module  172  may selectively control the motor  142  to vary one or more parameters of oral irrigator  100 . The massage module  172  may include a signal generator  166  as well as one or more processing elements  170 . The processing element  170  may be one or more processors or control chips that may process and execute instructions. The signal generator  166  may be substantially any type of component that may create voltage signals to control one or more characteristics of the motor  142 . For example, the signal generator  166  may create one or more repeating or non-repeating electronic signals (e.g., voltage waveforms) that may be applied to the motor  142 . In a particular implementation, the signal generator  166  may be a function generator that may produce electrical waveforms over a range of frequencies. Exemplary waveforms include sinusoidal waves, square waves, sawtooth waves, triangular waves, and so on. Additionally, the signal generator may be configured to create modified waves that include characteristics of two or more waveforms. Illustrative waveforms that may be used will be discussed in more detail below with respect to  FIGS. 8A-8C . 
       FIG. 6  is a simplified circuit diagram of the massage module  172 . With reference to  FIGS. 5 and 6 , the signal generator  166  may be in communication with an amplifier  174  and a gate  176  or switch. The signal generator  166  may be in communication with the processor element  170 , which may determine the signals generated by the signal generator  166 . In some examples, the signal generator  166  may be incorporated into the processing element  170 , such that the processing element  170  may perform the functions of the signal generator  166  and may create and apply signals to the motor. 
     The signal generator  166  may be in communication with an amplifier  174 . The amplifier  174  may amplify a signal generated by the signal generator  166  prior to applying the signal to the motor. For example, the amplifier  174  may be an operational amplifier or a differential amplifier. The amplifier  174  may be in communication with the motor  142  as well as the signal generator  166 . In some examples, the amplifier  174  may be configured to receive feedback from its output, in order to provide a more consistent output signal. However, it should be noted that the configuration of the amplifier  174 , as well as the type of amplifier and inputs used may be varied based on the type of motor  142  and signal generator used  166 . Additionally, depending on the output voltage of the signal generator and/or other system characteristics, the amplifier  174  may be omitted. In these instances, the signal may be directly or indirectly applied to the motor without being amplified. 
     The amplifier  174  may be in communication with a gate  176  or switch. The gate  176  may selectively provide the output of the amplifier  174  (which may be a signal produced by the signal generator  166 ) to the motor  142 . For example, when the gate is not activated, the motor  142  may not receive a signal from the signal generator, but may receive a constant power signal. As another example, when the gate is not activated, the motor  142  may be separated from any signal or power source, preventing the motor from being activated. In this example, the gate  176  provides power to the motor and the signal produced by the signal generator varies the signal transmitted through the gate and during normal mode the motor receives a constant voltage signal and during massage mode the motor receives a variable signal. As yet another example, the activation voltage for the gate  176  may be varied to control the current transmission to the motor. In particular, the gate  176  may be turned slightly activated during one mode allowing a reduced amount of current to travel between its source and drain (when the gate is a transistor) and then may be fully activated to allow full current flow. The variation in current may be used to pulse the signal to the motor or may be used to slow the motor down. 
     The gate  176  may be a switch or other selectively activated component. In one example, the gate  176  may be a transistor, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), such as an N-channel MOSFET. However, other types of transistors or gates are also envisioned, as well as other components that may be used to selectively provide communication between two or more components. 
     The massage module and other control circuitry of the oral irrigator may be implemented in a number of different manners, which may vary as desired.  FIGS. 7A-7D  illustrate various circuit schematics that may be used to implement one or more functions of the oral irrigator, control circuitry, and/or massage module. However, it should be noted that the electrical components, such as resistors, capacitors, and/or gates illustrated may be otherwise configured, omitted, or varied based on a number of a different factors. As such, the schematics illustrated in  FIGS. 7A-7D  are meant as illustrative and not limiting. 
       FIG. 7A  is an illustrative circuit schematic of the control circuitry for one example of the oral irrigator. With reference to  FIG. 7A , the circuitry  164  may include a number of electrical components, such as traces, resistors, switches or transistors, and amplifier. The schematic illustrated in  FIG. 7A  is one example only and the exact components and structures for implementing the massage module may be varied as desired and based on the constraints and parameters of the particular oral irrigator or other device incorporating the massage module. 
       FIG. 7B  illustrates a second example of a schematic for the oral irrigator. In the example shown in  FIG. 7B , the voltage source may be 12V and the processing element  170  and the switch  148  may control operation of the oral irrigator  100 . The schematic may also include a second control element  171  that may control a clock signal, data, a reset function, and the like for the oral irrigator. The second control element  171  may be in electrical communication with the processing element  170 . 
       FIG. 7C  illustrates a third example of a schematic for the oral irrigator. In the example shown in  FIG. 7C , the voltage source may be higher than the example shown in  FIG. 7B  and may include a fuse  181  to help regulate spikes in current and/or voltage. As shown in  FIG. 7B , the second control element  171  may also be used to provide clock signals and resets for the oral irrigator  100  and the switch  148  may provide communication between one or more of the control actuators  110 ,  112 ,  113 ,  124  with the processing element  170 . 
       FIG. 7D  illustrates a diagram of the switch  148  and light module. With reference to  FIGS. 7B, 7C, and 7D , the switch  148  module may be in communication with the processing element  170 , the lights  117   a ,  117   b , the second control actuator  112 , and the third control actuator  113 . With reference to  FIG. 7D , when the second control actuator  112  is activated by the user, the switch  148  may provide a signal to the processing element  170 , which may activate the oral irrigator  100 . Additionally, the switch  148  may activate the first light  117   a  to indicate that the oral irrigator  100  has been activated and is in the normal mode. For example, the normal or clean mode may be a default mode that may be activated when the oral irrigator  100  is initially activated. 
     With continued reference to  FIGS. 7B, 7C and 7D , when the second control actuator  113  is activated by the user, the switch  148  may provide a signal to the processing element  170  indicating that the user has activate the massage mode or second mode. Additionally, the switch  148  may illuminate the second light  117   b  to indicate to the user that the massage mode has been activated. In the example shown in  FIG. 7D , both lights  117   a ,  117   b  may be light emitting diodes. However, in other embodiments, other light sources are envisioned. 
     With reference again to  FIGS. 1A-6 , in operation, the user may rotate, push, or otherwise provide an input to the second control actuator  112 . The second control actuator  112  may activate the oral irrigator  100 , causing the power supply  115  to provide power to the control circuitry  164  and the motor  142 . During normal operation, control circuitry  164  will provide a normal control signal to the motor  142 . For example, the voltage or power source  115  may be placed into communication with the motor  142  and may provide a substantially constant control signal to the motor  142 . As the motor  142  receives the constant control signal, the motor  142  may begin turning the drive shaft  143 , moving the piston  145 . As the piston moves, fluid from the reservoir  104  may be pulled through the valve  158  into the pump  146  and be pushed through the outlet  154  of the valve fitting  152  into the hose  118 . The fluid may then travel through the hose  118  to the handle  108  and exit out of the tip  114 . 
     During normal operation, the control signal to the motor  142  may be substantially constant, causing the motor  142  to rotate the drive shaft in a constant manner (e.g., having a constant velocity). In examples where a piston pump or other reciprocating pump is used, the fluid may be slightly pulsed as it is expelled from the tip  114 . This is due to the reciprocating nature of the pump, e.g., the alternating pulling and pushing to alternately pull fluid from the reservoir  104  and push fluid from the pump out to the tip  114 . Depending on the type, size, or the like, the pulses during normal operation may have a somewhat short duration and fast frequency. In one example, the pulses due to the reciprocating nature of the pump  146  may be about 26 pulses per second. However, in other examples, during normal mode, the fluid outlet may not be pulsed, but may be substantially constant. For example, in examples where a non-reciprocating pump is used, the output during normal mode may be substantially constant. 
     During use, if the user hits the pause actuator  124 , a valve within the handle  106  may reduce or substantially prevent fluid from exiting the tip  114 . Alternatively or additionally, the fourth control actuator  124  may transmit a signal to the processing element  170  that may temporarily stop movement of the motor  142 , to prevent or reduce fluid transmitted from the reservoir  104  to the tip  114 . Also, if the first control actuator  110  is activated, the user may selectively adjust the pressure of fluid expelled from the tip  114 . 
     If massage mode is activated, such as by a user providing an input to the oral irrigator  100  through one of the control actuators  110 ,  112 ,  113 ,  124 , the fluid output characteristics may be modified. For example, the third control actuator  113  may be used to activate a massage mode for the oral irrigator  100 . During massage mode, the processing element  170  may selectively activate the gate  176 , to vary the signal provided to the motor  142 . In one example, the signal generator  166  may apply a varying signal to the motor  142 , which may cause the motor  142  to selectively vary one or more movement characteristics. For example, the signal generator  166  may apply a signal that has a variable voltage across a predetermined time duration. The signal may vary not only in voltage magnitude, but also in time between a high voltage and a low voltage (e.g., frequency). 
     With reference to  FIG. 6 , the amplifier  174  may increase the signal generated by the signal generator  166  and provide the increased control signal to the motor  174 . The control signal may selectively interrupt or vary the power supplied to the motor  142 , causing the motor to intermittently stop or slow down, reducing, stopping, or changing the movement of the drive shaft  143 . As the drive shaft  143  varies, the piston  145  may also vary, which may increase the length of pulses produced by the pump  146 , as well as the pressure output by the pump  146 . As an example, when the control signal is low or otherwise prevents power from being transmitted to the motor, the motor  142  may stop rotating the drive shaft  143 , which may in turn, stop movement of the piston  145 , reducing or stopping fluid from flowing from the reservoir  104  to the tip  114 . 
     Specifically, one control signal may be configured create 0.5 second pulses. In other words, the pump  146  may produce 2 pulses per second, with may have a substantially slower pulse rate than the pulse rate due to the reciprocating nature of the pump, and each pulse may have a substantially longer duration as compared to the normal mode. However, it should be noted that other pulse rates are envisioned and will be discussed in more detail below with respect to  FIGS. 8A-8C . 
     In some implementations, the flow rate of the oral irrigator during massage mode may be reduced as compared to the flow rate during normal mode. As a specific example, the massage mode flow rate may be between 40 to 70 percent and often 50 to 60 percent of the flow rate during normal mode. In some implementations, the oral irrigator  100  may have a flow rate during clean mode ranging between 300-400 mL per minute and often may be about 370 mL per minute and during massage mode the flow rate may range between 150-200 mL per minute or lower and often may be 222 mL per minute. 
     In addition to changing the pulse rate, the control signal may also vary the magnitude of power provided to the motor  142 , which may increase or decrease the outlet pressure of the pump  142 . In a specific implementation, the outlet pressure of the oral irrigator during cleaning mode may range between 70 to 95 psi, and often average between 90-93 psi and during massage mode may range between 60 to 90 psi, and often average between 80-87 psi.  FIGS. 9A and 9B  illustrate example pressure ranges for the oral irrigator during normal mode and during massage mode. For example, by applying an increased voltage to the motor  142 , the current supplied to the motor  142  may also increase, increasing the torque of the motor  142 . The increased torque may exert an increased force on the piston  145 , to increase the output pressure of the oral irrigator  100 . Accordingly, in some examples, the control signal may vary not only the durations for which a voltage is applied to the motor, but also the magnitude of the voltage in order to vary not only the fluid pulses but also the fluid pressure output by the oral irrigator  100 . 
     As the fluid exits the tip  114 , the user may direct the flow on his or her teeth, gums, tongue, cheeks, or the like. The varying control signals may vary the fluid output by the tip  114 . In some examples, the variation in fluid may create a massage effect on a user&#39;s gums. For example, during each pulse fluid may not exit from the tip  114 , allowing blood to return to the user&#39;s gums before the next fluid stream hits the gums. This may provide a massaging effect, as well as may stimulate blood flow to the gums and enhance the cleaning experience with the oral irrigator. 
     The signal generator  166  may vary a frequency and magnitude of the control signal based on a desired output pulse rate and fluid pressure.  FIGS. 8A-8C  illustrate control signals that may be created by the signal generator to be applied to the motor  142 . The control signals may include one or more voltage peaks and voltage minimums. As some illustrative examples, the voltage peaks may be 170V, 12V, 6V, or other values and the voltage minimums may be a subset of the voltage peaks and often may be substantially or about 0V. However, it should be noted that many other voltage values are envisioned and the voltage of the control signal may depend on the motor, the processing element, and other system parameters and as such may be modified as desired. 
     With reference to  FIG. 8A , a control signal  200  may be a square wave having a voltage peak  202  or amplitude and a voltage minimum  204 . In some examples, the voltage peak  202  (i.e., maximum voltage) may be applied for a duration T 1  and the voltage minimum  204  may be applied for a duration T 2 . In this example, the durations T 1  and T 2  may be approximately equal. In a particular implementation, the peak voltage  202  may be approximately 12 V and the minimum voltage  204  may be 0 V, additionally both durations T 1  and T 2  may have a length of approximately 100 ms. 
     When the control signal  202  of  FIG. 8A  is applied to the motor  142 , during the duration T 2  of the minimum voltage  204 , the motor  142  may not receive power. In other words, because the minimum voltage  204  is set to 0 V, the motor  142  may not be powered. As the motor  142  does not receive power during the duration of the minimum voltage  204 , the drive shaft  143  may slow down and stop moving, stopping movement of the piston  145  within the pump  146 . Thus, during the duration T 2 , the pump  146  may not pump fluid, creating a pause in fluid flow. Then, when the peak voltage  202  is applied, the motor  142  may begin rotating the drive shaft  143 , causing the piston  145  to push fluid from the pump  146 , creating fluid flow. In this example, the minimum voltages  204  may define the “pulse” length, or the intermission between fluid output. 
     With continued reference to  FIG. 8A , in another example, the maximum voltage  202  may be selected to be approximately 12V and the minimum voltage  204  may be selected to be approximately 6 V or half of the maximum voltage. However, in other embodiments, the minimum voltage may be 0V in this example as well. Additionally, the two time durations may be selected to be 160 ms. In this example, during second duration T 2  when the minimum voltage  204  is applied to the motor  142 , the motor  142  may receive some power, but the power may be reduced as compared to the maximum voltage  202 . In this example, the motor  142  may still rotate the drive shaft  143 , but may do so at a reduced torque and speed, which may also cause a reduced flow rate and pressure output by the pump  146 . In this example, during each pulse, fluid may be output from the tip  114 , but at a slower flow rate and pressure. 
     In yet another implementation, the time durations T 1  and T 2  may be selected to be 250 ms. In these examples, the frequency of the pulses may be reduced, such that there may be fewer pulses per second as compared to examples where the time durations may be shorter. 
     In  FIG. 8A , because the time durations T 1  and T 2  may be substantially equal, the time of fluid output and fluid pause may be substantially the same. However, in other examples, the time durations for the maximum voltage and the minimum voltage may be varied. With reference to  FIG. 8B , a control signal  212  may include a voltage maximum  212  having a duration T 3  and a voltage minimum  214  having a duration T 4 . In this example, the peak time duration T 3  may be shorter than the minimum time duration T 4 , which may result in longer “pauses” in fluid flow or pulses. The time duration T 4  may be twice, three times, or more, the length of the peak time duration T 3 . 
     As one example, the minimum voltage time duration T 4  may be three times as long as the maximum voltage time duration T 3 . Thus, the pause in fluid flow may last three times as long as the fluid flow segments or pulses. In a specific implementation, the maximum voltage  212  may be 12V and may have time duration T 3  of 100 ms, the minimum voltage  214  may be 0V and may have a duration of 300 ms. However, the above values are illustrative only and many other implementations are envisioned. Furthermore, although the control signal  210  in  FIG. 8B  is illustrated as having a longer low voltage duration T 4  than maximum voltage duration T 3 , in some examples, the maximum voltage time duration T 3  may be longer than the minimum voltage time duration T 4 . In these examples, the pauses or breaks between fluid flow may be reduced as compared to the fluid stream time durations. 
     In the control signals  200 ,  210  illustrated in  FIGS. 8A and 8B , there may be a rapid transition between the maximum or peak voltage  202 ,  212  and the minimum voltage  204 ,  214 . For example, both control signals  200 ,  210  may be square waves that substantially instantaneously transition between minimum and maximum values. However, in other examples, the control signal may gradually transition between a maximum and minimum voltage. 
     With reference to  FIG. 8C , a control signal  220  having a sinusoidal shape is illustrated. The control signal  220  may have a peak voltage  220  and a minimum voltage  224 , with the peak voltage  220  having a time duration T 5  and the minimum voltage having a time duration T 6 . However, because the control signal  220  may gradually change between the maximum and minimum levels, the durations T 5  and T 6  may represent the time between inflection points  226 ,  228 . The inflection points  226 ,  228  generally may represent half of a cycle or period for the control signal  220 . In other words, the sum of the durations T 5  and T 6  may represent the period for the control signal  220 . 
     Using the control signal  220  of  FIG. 8C , the motor  142  may more subtly transition between the high and low states of fluid flow. That is, the transition between the “pulses” may be tapered so that there may not be a sudden reduction in fluid flow, but a more gradual reduction. In some examples, the peak voltage  222  may be three times as large as the minimum voltage  224 . As one example, the peak voltage  222  may be selected at 15V and the minimum voltage  224  may be selected at 3V. In this example, the period of the control signal  220  may be 1800 ms with the high duration T 5  being 900 ms and the low duration T 6  being 900 ms. Although the control signal  222  shown in  FIG. 8C  is a sine wave, other waveforms are envisioned, such as combination waveforms (e.g., having characteristics of multiple wave types), elliptical waveforms, and the like. Accordingly, the discussion of any particular waveform is meant as illustrative only. 
     The massage module  172  may not only vary the pulse rate fluid flow of the oral irrigator, but may also vary an outlet fluid pressure for the oral irrigator.  FIG. 9A  is a chart illustrating an example outlet pressure of the oral irrigator during clean mode.  FIG. 9B  is a chart illustrating an example outlet pressure of the oral irrigator during massage mode. With reference first to  FIG. 9A , the oral irrigator  100  may pulse rapidly (which may be due to the reciprocating nature of the pump) and the outlet pressure  240  may vary between peaks  242  and valleys  244 . As can be seen from the graph in  FIG. 9A , each pressure peak  242  may be generally close together with a pressure pulse rate of just over 21 peaks per second. Additionally, the average pressure for the peaks  242  may be 91.8 psi and generally the pressure at the peaks  242  ranges between 91 and 92 psi. The example outlet pressures discussed herein are meant as illustrative only and may be higher or lower based as desired. 
     With continued reference to  FIG. 9A , the output pressure  240  may also drop to the valleys  244 , which may hover around 0 psi before the pressure ramps back up extend towards a pressure peak  242 . Each of the valleys  244  may occur while the piston  145  in the pump  146  is drawing fluid into the pump chamber before it expels the fluid and are therefore due to the reciprocating nature of the pump  146 . Accordingly, in examples where a non-reciprocating pump may be used, the outlet pressure during normal mode may be substantially constant. 
     With reference now to  FIG. 9B , during massage mode, the outlet pressure  250  of the oral irrigator  100  may be lower than during clean mode (shown in  FIG. 9A ) and may also have non-pulsating periods during which the outlet pressure may be close to or at 0 psi. For example, the outlet pressure  250  may include a high pressure period T high  and a low pressure period T low . During the high pressure period T high , the outlet pressure  250  may include a plurality of pressure peaks  252 , as well as ramp peaks  256  that are the pressure peak while the oral irrigator  100  is transitioning between the high pressure period and the low pressure period. Additionally, the outlet pressure  250  may include valleys  254 ,  258 . The first valley  254  may be during the high pressure T high  period and may be due to the reciprocating nature of the piston  145 , as discussed above with respect to  FIG. 9A . The second valley  258  represents the low pressure period between pulses of high pressure. During the low pressure period T low , the oral irrigator  100  may output little to no pressure. 
     As shown in  FIG. 9B , in some examples, the oral irrigator  100  may have an average outlet pressure of 85.9 psi during massage mode. As with the clean mode, many other outlet pressures are envisioned and the above examples are meant as illustrative only and not limiting. 
     A method for operating the oral irrigator  100  including the massage module  172  will now be discussed in more detail.  FIG. 10  is a method  300  for activating the massage mode. The method  300  may begin with operation  302  and the irrigator  100  may be activated. For example, the second control actuator  112  may be selected by a user to turn on the oral irrigator  100 . Once the oral irrigator  100  is activated, the method  300  may proceed to operation  304 . In operation  304 , the processing element  170  may determine whether massage mode has been activated. For example, the processing element  170  may determine whether a user has provided an input to one of the control actuators  110 ,  112 ,  124  to select the massage mode. In a specific implementation, the switch  148  may provide an input to the processing element  170  when the second control actuator is activated. As another example, the massage mode may be activated automatically after a select time period of activation of the irrigator  100 , e.g., after 30 seconds of operation, the massage mode may be automatically activated. 
     If the massage mode is not activated, the method may proceed to operation  314 , which will be discussed in more detail below. However, if in operation  304  the massage mode is activated, the method  300  may proceed to operation  306 . In operation  306 , the signal generator  166  may generate a control signal  200 ,  210 ,  220 . The control signal generated  200 ,  210 ,  220  may be selected from a predetermined signal, or as will be discussed in more detail below with respect to  FIG. 10 , may be generated based on one or more user inputs. 
     Once the signal generator  166  has generated the control signal  200 ,  210 ,  220 , the method  300  may proceed to operation  308 . In operation  308  the control signal may be applied to the motor. For example, the gate  176  may be activated to provide the control signal from the signal generator  166  to the motor  142 . As the control signal is applied to the motor  142 , the motor  142  may drive the drive shaft  143  based on the signal. For example, the motor  142  may selectively slow down or stop rotation of the drive shaft and/or may decrease or reduce the torque produced by the drive shaft. The variations in the drive shaft movement may create related changes in the piston  145 , thus varying the output of the pump  146 , changing the output characteristics of the fluid flow from the tip  114 . 
     After operation  308 , the method  300  may proceed to operation  312 . In operation  312 , the processing element  170  may determine whether to end massage mode. For example, the user may provide a second input to the oral irrigator  100 , e.g., by selecting one of the control actuators  110 ,  112 ,  124 , to indicate that he or she wishes to resume normal mode. As another example, the oral irrigator  100  may have a predetermined time period for massage mode (e.g., 1 minute, or the like), and the processing element  172  may determine to end massage mode once the allotted time has passed. 
     In operation  312 , if massage mode is not terminated, the method  300  may proceed to operation  310 . In operation  310 , the method  300  may determine whether the same control signal  200 ,  210 ,  220  should be applied to the motor or whether a different signal should be applied. If the control signal is to remain the same, the method  300  may return to operation  308  and the signal may continue to be applied to the motor  142 . However, in operation  310  if a new signal is desired, the method  300  may return to operation  306  and the signal generator  166  may generate a new control signal. For example, in some examples, a user may wish to vary pressure, pulse rate, or the transition between pulses during massage mode. In these instances, the processing element  170  may receive a user input to vary the control signal and may instruct the signal generator  166  to create a new control signal or vary the current control signal. 
     With continued reference to  FIG. 10 , if in operation  312  massage mode is terminated, the method  300  may proceed to operation  314 . In operation  314  the processing element  170  may provide a constant signal to the motor  142 . In other words, the normal mode signal may be applied to the motor, and in some instances, the normal mode signal may be substantially constant. As the motor  142  receives the normal mode signal, movement of the drive shaft  143  may be constant, and any pulses in the fluid output may be due to the reciprocating nature of the pump  146 , rather than variable movement in the motor. 
     After operation  314 , the method  300  may proceed to operation  316 . In operation  316 , the processing element  170  may determine whether more cleaning is desired. For example, the processing element  170  may determine whether the user has deactivated the power control actuator  112 . As another example, the oral irrigator may be configured to have an activation time corresponding to a predetermined “cleaning” length and once the time length has expired, the oral irrigator  100  may automatically shut off. 
     If more cleaning is desired, the method  300  may return to operation  304 . However, if no additional cleaning is desired, the method  300  may proceed to operation  318 . In operation  318 , the processing element  170  may deactivate the motor. As one example, the processing element  170  may switch off a connection between the power supply  115  and the motor  142 . After operation  318 , the method  300  may proceed to an end state  320 . 
     In some examples, the pressure and pulse rate of the massage mode may be statically set. However, in other examples, the pressure and pulse rate of the pulses during massage mode may be dynamically modifiable or may be initially set by a user (e.g., calibrated to a particular user&#39;s preferences).  FIG. 11  is a flow chart illustrating a method for dynamically modifying one or more characteristics of the fluid flow during massage mode. With reference to  FIG. 11 , the method  400  may begin with operation  402 . In operation  402 , massage mode for the oral irrigator  100  may be activated. For example, the user may select one of the control actuators  110 ,  112 ,  124  to indicate his or her desire to enter massage mode. Once in massage mode, as described in operations  306  and  308  in  FIG. 9 , the signal generator  166  may generate a signal and apply the signal to the motor  142 . 
     Once massage mode has been activated, the method  400  may proceed to operation  404 . In operation  404 , the processing element  170  may determine whether the outlet pressure should be varied. For example, on the control actuators  110 ,  112 ,  124  may be used to allow the user to provide an input indicating whether he or she wishes for the pressure to be increased or decreased. In a particular example, rotating one of the control actuators  110 ,  112 ,  124  in a first direction may correspond to an increase in pressure and rotating in a second direction may correspond to a decrease in pressure. 
     If the pressure is to be varied from the current control signal output, the method  400  may proceed to operation  406 . In operation  406  the processing element  170  may determine whether the pressure should be increased. In other words, the processing element  170  may determine whether the user input to vary the pressure corresponds to an increase in pressure or a decrease. It should be noted that in many implementations, operations  404  and  406  may be performed substantially simultaneously. For example, the processing element  170  may receive a single input that indicates both a change a pressure, as well as whether the pressure is to be increased or decreased. 
     In operation  406 , if the pressure is going to be decreased, the method  400  may proceed to operation  408 . In operation  408 , the control signal  200 ,  210 ,  220  may be modified by the processing element  170  to reduce the maximum voltage  202 ,  212 ,  222 , or reduce the amplitude of the control signal. As discussed above with respect to  FIGS. 8A-8C , by decreasing the maximum voltage of the control signal, the output pressure by the pump  146  may be reduced due to a reduction in output torque by the motor. However, it should be noted that in other examples, the pressure may be decreased manually, such as by a user closing or opening a valve, such a by-pass valve or the like. In these examples, the control signal may not be modified, but the mechanical properties of the fluid path between the reservoir  104  and the tip  114  may be changed. 
     If in operation  406  the pressure is going to be increased the method  400  may proceed to operation  410 . In operation  410 , the peak voltage  202 ,  212 ,  222  or amplitude of the control signal  200 ,  210 ,  220  may be increased. As a specific example, the peak voltage may increase from 10 V to 12V. As discussed above, the outlet pressure may be related to the voltage applied to the motor  142  by the control signal, such that a change in the voltage may correspond to a change in pressure. 
     After either operation  408  or  410 , the method  400  may proceed to operation  412 . In operation  412 , the processing element  170  may determine whether the pulse length and/or pulse rate should be varied. For example, the user may be provide input to the oral irrigator  100  through one or more of the control actuators  110 ,  112 ,  124  indicating his or her desire to increase the pulse rate or length. 
     If the pulse rate is going to be varied, the method  400  may proceed to operation  414 . In operation  414 , the processing element  170  may determine whether the pulse rate is going to be increased. For example, the user input to vary the pulse rate may also include an indication of whether the pulse rate should be increased or decreased. Additionally, as discussed above with respect to pressure, in some examples, the user input indicating that the pulse rate should be varied may also include data indicating whether the pulse rate should be increased or decreased. 
     In operation  414 , if the pulse rate is going to decrease, the method  400  may proceed to operation  416 . In operation  416 , the signal generator  166  may decrease the frequency of the control signal  200 ,  210 ,  220 . As an example, the duration T 1 , T 2 , T 3 , T 4 , T 5  may be increased, such that the cycles per unit of time of the control signal may be increased, reducing the number of pulses per second. 
     In operation  414  if the pulse rate is going to be increased, the method  400  may proceed to operation  418 . In operation  418 , the signal generator  166  may increase the frequency of the control signal. For example, the duration T 1 , T 2 , T 3 , T 4 , T 5  for the control signal may shorten, increasing the number of cycles of the control signal per minute. By shortening the length of the maximum and minimum voltages applied to the motor  142 , the length of each pulse may be shortened, increasing the number of pulses per time frame. 
     After operations  416  or  418  or if in operation  412  the pulse rate is not going to be changed, the method  400  may proceed to an end state  420  and may terminate. It should be noted that the method  400  is an illustrative method for varying one or more characteristics of the fluid flow through the tip  114  during massage mode. However, many other methods are envisioned. As one example, the transition between high and low or fluid flow and a pulse may be varied by changing the transition between the maximum and the minimum voltage levels in the control signal. As another example, the length of fluid flow as compared to pulses or breaks in fluid flow may be varied by changing the duration T 1 , T 2 , T 3 , T 4 , T 5  that either the maximum voltage or the minimum voltage is applied to the motor  142 . 
     Other Examples 
     As generally discussed above, the processing element  170  may vary a control signal to the motor to change either or both the fluid pulse rate and/or the fluid outlet pressure. In other examples, the processing element  170  may activate a switch or valve to vary the pulse rate and/or pressure. As a first example, the processing element  170  may be in communication with an electrical valve such as a solenoid valve and when the massage mode is activated, the processing element  170  may vary the outlet of the valve to change the pressure and/or may selectively open and close the valve to change the flow rate of the oral irrigator  100 . As a second example, the oral irrigator  100  may include a gear driven turbine or a water driven turbine that may be mechanically actuated or actuated by the processing element  170  to vary the flow rate of the oral irrigator  100 . 
     CONCLUSION 
     The foregoing description has broad application. For example, while examples disclosed herein may focus on a massage mode for oral irrigators, it should be appreciated that the concepts disclosed herein may equally apply to other motor driven devices where a variation in motion may be desired. Similarly, although the massage module is discussed with respect to reducing a pulse rate to create a massage feeling, the devices and techniques disclosed herein are equally applicable to modifying the pulse rate or pressure of an outlet fluid for other applications (e.g., creating a faster pulse rate for quicker or more effective cleaning). Accordingly, the discussion of any example is meant only to be exemplary and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these examples. 
     Although the present invention has been described with reference to preferred examples, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. The invention is limited only by the scope of the following claims.