Patent Publication Number: US-2005130097-A1

Title: System and method for remotely controlling devices

Description:
This application is a divisional application of U.S. patent application Ser. No. 10,730,678, filed Dec. 8, 2003. U.S. patent application Ser. No. 10,730,678 is a continuation-in-part of U.S. application Ser. No. 10/464,369, filed on Jun. 17, 2003 that claims priority to U.S. Provisional Ser. No. 60/389,229, filed on Jun. 17, 2002. 
    
    
     FIELD OF THE INVENTION  
      This invention relates to a system and method for the remotely controlling devices.  
     BACKGROUND OF THE INVENTION  
      Dental professionals generally utilize a plurality of dental devices when performing dental procedures on patients. Each device or implement is generally controlled using a foot pedal. Thus, a dental operatory room generally has a plurality of foot pedals located on the floor to allow the dentist to control the plurality of devices. The inventor herein has recognized that multiple foot pedals and their associated conduits and cords are a hindrance to the operator&#39;s mobility due to multitude of different foot pedals and their associated conduits and cords. Further, because the foot pedals are not standardized, each foot pedal often has a different level of control or “feel” such that the operator of the pedals fails to achieve a consistent level of control among the devices. Further, multiple foot pedals may cause confusion and increase the risk of an inadvertent activation of one of the foot pedals. Further, when a device associated with a foot pedal needs to be moved within an operatory room or between operatory rooms, an asepsis or contamination problem may occur. In particular, the operatory room floor and the foot pedal or cable associated with the foot pedal may not be sufficiently clean such that when the device is moved with the associated pedal, the pedal may undesirably contaminate the device.  
      Accordingly, the inventor herein has recognized that a need exists for an improved foot pedal control unit that reduces the number of foot pedals needed to control a plurality of dental or medical instruments.  
     SUMMARY OF THE INVENTION  
      The foregoing problems and limitations are reduced and/or eliminated by a system and a method for remotely controlling devices described herein.  
      A system for remotely controlling devices is provided. The system includes a foot pedal unit having a moveable member. The system further includes a transmitter operatively associated with the moveable member. The transmitter transmits a first signal in response to at least partial displacement of the moveable member when a first device is selected. The transmitter transmits a second signal in response to at least partial displacement of the moveable member when a second device is selected.  
      A method for remotely controlling devices is provided. The method includes transmitting a first signal in response to at least partial displacement of a moveable member on a foot pedal unit when a first device is selected. The method further includes transmitting a second signal in response to at least partial displacement of the moveable member on the foot pedal unit when a second device is selected. Finally, the method includes controlling the first device based on the first signal.  
      The system and method for remotely controlling devices provides a substantial advantage over other systems and methods. In particular, the system and method provide a foot pedal unit having one movable member that can be utilized to control multiple devices. Thus, an operator of the foot pedal unit can obtain a consistent control of multiple devices. Further, the single foot pedal unit can replace a plurality of other foot pedal providing for a less cluttered operatory floor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic of a system for remotely controlling devices including a handheld transmitter unit, a foot pedal control system, and a device actuation unit.  
       FIG. 2  is a detailed schematic of a handheld transmitter unit.  
       FIG. 3  is a detailed schematic of a first embodiment of a foot pedal control system.  
       FIG. 4  is a detailed schematic of a first embodiment of a device actuation unit.  
       FIG. 5  is a schematic of a foot pedal unit having a rotatable movable member.  
       FIG. 6  is a schematic of a foot pedal unit having a linearly displaceable movable member.  
       FIG. 7A  is a schematic of a “training mode message” transmitted from a handheld unit to a device actuation unit.  
       FIG. 7B  is a schematic of an “acknowledgment message” transmitted from a device actuation unit to a handheld unit after device actuation unit receives a “training mode message”.  
       FIG. 8A  is a schematic of a “device selection message” transmitted from a handheld unit to a foot pedal control system to select a device.  
       FIG. 8B  is a schematic of an “acknowledgment message” transmitted from a foot pedal control system to a handheld unit after the foot pedal control system receives a “device selection message.” 
       FIG. 9  is a schematic of a “device actuation message” transmitted from a foot pedal control system to a device actuation unit for “on-off” control of the device.  
       FIG. 10  is a schematic of a “device actuation message” transmitted from a foot pedal control system to a device actuation unit for the “variable” control of the device.  
       FIGS. 11A-11C  are flowcharts of a training method to transmit a Handheld ID from a handheld unit to a device actuation unit.  
       FIGS. 12A-12B  are flowcharts of a method to transmit a Device Actuation Unit ID from a handheld unit to a foot pedal control system.  
       FIGS. 13A-13B  are flowcharts of the method to transmit an “on-off” control message from a foot pedal control system to a device actuation unit.  
       FIG. 14  is a schematic of a second embodiment of a foot pedal control system.  
       FIG. 15  is a schematic of a foot pedal unit that can generate a signal indicative of a position of a moveable member in the foot pedal unit.  
       FIG. 16  is a schematic of a second embodiment of a device actuation unit.  
       FIG. 17  is a flowchart of the method to transmit a variable-control control message from the foot pedal control system of  FIG. 14  to the device actuation unit of  FIG. 16 .  
       FIG. 18  is a schematic of a device actuation unit operably coupled to a video image capture system.  
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION  
      Referring now to the Figures, like reference numerals are used to identify identical components in the various views. Referring to  FIG. 1 , a system  10  for remotely controlling devices is illustrated. System  10  may include a handheld unit  12 , a foot pedal control system  14 , and a device actuation unit  16 . System  10  may further include a device actuation unit  17 , a device actuation unit  18 , and devices  19 ,  20 ,  22 . Device actuation units  17 ,  18  may have a substantially similar hardware configuration as device actuation unit  16 . Although, system  10  will be described as utilizing RF signals to communicate with the various system components, it should be noted that in alternate embodiments of system  10 , infrared signals, near-infrared signals, or magnetic signals could be utilized for communicating with one or more of the various system components. It should be further noted that although only three device actuation units are illustrated in  FIG. 1 , a plurality of additional device actuation units (and devices attached thereto) could be controlled using foot pedal control system  14 .  
      Handheld unit  12  is provided to transmit RF signals each having a “training mode message” including a Handheld ID associated with handheld unit  12 . The “training mode messages” are transmitted to device actuation units  16 ,  17 ,  18  so that units  16 ,  17 ,  18  will respond to subsequent RF signals having messages containing the Handheld ID. Handheld unit  12  is also utilized to transmit an RF signal containing a “device selection message” to foot pedal control system  14  in order to select a specific device to be controlled by subsequent activation of foot pedal control system  14  by an operator. The foot pedal control system  14  is provided to transmit RF signals having a “device actuation message” including the Handheld ID to actuate a device connected to a predetermined device actuation unit. When the predetermined device actuation unit receives an RF signal having the “device actuation message” for the device actuation unit, the device actuation unit will actuate the device operably coupled to the device actuation unit.  
      Referring to  FIG. 2 , handheld unit  12  will now be described in further detail. As shown, unit  12  may include a central processing unit (CPU) or microprocessor  30 , read-only memory (ROM)  32 , random access memory (RAM)  34 , an input/output (I/O) interface  36 , a transceiver  38 , an antenna  39 , normally-open switches  40 ,  42 ,  44 ,  46 , light emitting diodes (LEDs)  48 ,  50 ,  52 ,  54 ,  56 , and a Handheld ID DIP switch  58 . CPU  30  of handheld unit  12  may be operably coupled to a battery (not shown) for supplying an operational voltage to CPU  30 . An advantage of handheld unit  12  is that device actuation units to be controlled by a foot pedal control system can be selected by an operator using handheld unit  12  from any location within an operatory room. Another advantage of handheld unit  12  is that all of the communication between handheld unit  12  and the other system  10  devices are “wireless” communications thus eliminating any need for a plurality of communication wires from unit  12  to a plurality of devices to be trained or controlled.  
      Transceiver  38  is provided to transmit and receive RF signals via antenna  39 . Thus, transceiver  38  operates as both an RF transmitter and an RF receiver. Transceiver  38  may receive and transmit RF signals in one or more frequency ranges (e.g., UHF, VHF, or microwave frequency). Further, transceiver  38  may modulate an RF signal containing a message using one or more modulation techniques (e.g., amplitude modulation (AM), frequency modulation (FM), frequency shift keying (FSK)) used by those skilled in the art. Further, transceiver  38  may transmit or pulse each RF signal for a predetermined time interval, such as 15 milliseconds for example. In an alternate embodiment, transceiver  38  could be replaced with an infrared transceiver (or infrared transmitter and/or infrared receiver) configured to transmit and receive infrared signals or near-infrared signals. In another alternate embodiment, transceiver  38  could be replaced with a magnetic transceiver (or magnetic transmitter and/or magnetic receiver) configured to transmit and receive magnetic signals. In the illustrated embodiment, transceiver  38  may receive an RF signal containing a predetermined message and transmit a sequence of binary numbers representing the message to CPU  30 . It should be noted that transceiver  38  could be replaced with a single RF transmitter if “handshaking” communication is not desired between (i) handheld unit  12  and the device actuation units, or (ii) handheld unit  12  and the foot pedal control system.  
      CPU  30  operates in a “training mode” when an operator closes training mode switch  46  and induces training mode LED  56  to emit light. Thereafter, when an operator closes one of selection switches  40 ,  42 ,  44  for selecting devices  19 ,  20 ,  22 , respectively, CPU  30  induces transceiver  38  to transmit an RF signal having a “training mode message.” Referring to  FIG. 7A , a “training mode message” includes the following attributes: (i) a Handheld ID, (ii) a Message Length, (iii) a Device Actuation Unit ID, (iv) a Training Mode Code, and (v) a Checksum. The Handheld ID may correspond to an 8-bit number determined from DIP switch  58 . In particular, CPU  30  reads the 8-bit number designated by the selector switch  58  to determine the Handheld ID and then stores the 8-bit number in ROM  32 . For example, in  FIG. 2 , CPU  30  can read the value “11111111” designated by DIP switch  58  and then store the value “11111111” in ROM  32 . The Handheld ID will be used as an identifier for subsequent communications between handheld unit  12 , foot pedal control system  14 , and device actuation units  16 ,  17 ,  18 . The Message Length value corresponds to an 8-bit number representing the number of bytes of data in the “training mode message.” The Training Mode Code corresponds to a unique number specifying that a transmitted message is a “training mode message.” The Checksum value corresponds to a calculated checksum based on the Device Actuation Unit ID and the Training Mode Code—for checking the accuracy of a transmitted “training mode message.” In particular, the Checksum value may be determined by adding together the Device Actuation Unit ID and the Training Mode Code.  
      Referring to  FIG. 2 , distinct addresses (i.e., Device Actuation Unit IDs) may be stored in ROM  32  for each of switches  40 ,  42 ,  44 . For example, switches  40 ,  42 ,  44  may have corresponding Device Actuation Unit ID&#39;s “00000001”, “00000010”, “00000011”, respectively, that are stored in ROM  32 . Thus, for example when CPU  30  is in a “training mode” operation and an operator closes switch  42 , the transmitted “training mode message” would have a device actuation unit ID of “00000010.” 
      CPU  30  operates in a “device selection mode” when training mode switch  46  is an open operational position. Thereafter, when an operator closes one of selection switches  40 ,  42 ,  44  for selecting devices  19 ,  20 ,  22 , respectively, CPU  30  induces transceiver  38  to transmit an RF signal having a “device selection message” which will be received by foot pedal control system  14 . Referring to  8 A, the “device selection message” includes the following attributes: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, and (v) Checksum. The Checksum value in the “device selection message” is identical to the Device Actuation Unit ID.  
      CPU  30  can induce LEDs  48 ,  50 ,  52  to emit light when selection switches  40 ,  42 ,  44 , respectively, are in a closed operational position. CPU  30  induces LED  54  to emit light when a valid RF signal is being received by transceiver  38 . CPU  30  induces LED  56  to emit light when the training mode switch  46  is in a closed operational position.  
      Referring to  FIG. 3 , foot pedal control system  14  will now be described in further detail. Foot pedal control system  14  is provided to transmit RF signals each having a “device actuation message,” including the Handheld ID, to actuate a device connected to a predetermined device actuation unit. As shown, foot pedal control system  14  includes a CPU  62 , ROM  64 , RAM  66 , (I/O) interface  68 , a transceiver  70 , an antenna  71 , light emitting diodes (LEDs)  72 ,  74 ,  76 ,  78 , a Handheld ID DIP switch  80 , an air pump  82 , a foot pedal unit  84 , a pneumatic switch or pressure sensor  94 , a pneumatically controlled dental implement  98 , a valve  96 , and conduits  86 ,  92 . CPU  62  of foot pedal control system  14  may be operably coupled to a battery (not shown) for supplying an operational voltage to CPU  62 . An advantage of foot pedal control system  14  is that all of the communication between foot pedal control system  14  and the other system  10  devices are “wireless” communications thus eliminating any need for a plurality of communication wires from foot pedal control system  14  to a plurality of devices to be controlled.  
      Transceiver  70  is provided to transmit and receive RF signals via antenna  71 . Thus, transceiver  70  operates as both an RF transmitter and an RF receiver. Transceiver  70  may receive and transmit RF signals in one or more frequency ranges (e.g., UHF, VHF, or microwave frequency). Further, transceiver  70  may modulate an RF signal containing a message using one or more modulation techniques (e.g., amplitude modulation (AM), frequency modulation (FM), frequency shift keying (FSK)) used by those skilled in the art. Further, transceiver  70  may transmit or pulse each RF signal for a predetermined time interval, such as 15 milliseconds for example. In an alternate embodiment, transceiver  70  could be replaced with an infrared transceiver (or infrared transmitter and/or infrared receiver) configured to transmit and receive infrared signals or near-infrared signals. In another alternate embodiment, transceiver  70  could be replaced with a magnetic transceiver (or magnetic transmitter and/or magnetic receiver) configured to transmit and receive magnetic signals. In the illustrated embodiment, transceiver  70  may receive an RF signal containing a predetermined message and transmit a sequence of binary numbers representing the message to CPU  62 . It should be noted that transceiver  70  could be replaced with a single RF transmitter if “handshaking” communication is not desired between foot pedal control system  14  and handheld unit  12 .  
      Distinct addresses (i.e., Device Actuation Unit IDs) may be stored in ROM  64  for each of LEDs  72 ,  74 ,  76 . For example, LEDs  72 ,  74 ,  76  may have associated Device Actuation Unit ID&#39;s “00000001”, “00000010”, “00000011”, respectively that are stored in ROM  64 . Thus, when CPU  62  receives a “device selection message” containing a Device Actuation Unit ID from handheld unit  12 , a corresponding LED will emit light. For example, when CPU  62  receives a “device selection message” containing a device actuation unit ID equal to “00000001”, CPU  62  can induce LED  72  to emit light. Further, CPU  62  can induce LED  78  to emit light when transceiver  70  is receiving an RF signal.  
      Referring to  FIGS. 8A, 8B , when CPU  62  receives a valid “device selection message” from handheld unit  12 , CPU  62  will generate an “acknowledgment message.” The “acknowledgment message” contains the following attributes: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, and (iv) Checksum. The Checksum value in the “acknowledgment message” is equal to the Device Actuation Unit ID value. For example, after receiving a valid “device selection message”  174 , CPU  62  can induce transceiver  70  to transmit an RF signal containing the “acknowledgment message”  176  to handheld unit  12 .  
      Referring to  FIG. 3 , Handheld ID DIP switch  80  is provided to select the Handheld ID that foot pedal control system  14  will respond to. For example, DIP switch  80  may be set to an 8-bit value of “11111111” corresponding to a Handheld ID. Thus, the Handheld ID specified by DIP switch  80  foot of pedal control system  14  should be equal to the Handheld ID specified by DIP switch  58  of handheld unit  12 .  
      The remaining components of foot pedal control system  14  will now be explained. Foot pedal unit  84  is provided to detect at least partial displacement of movable member  88  by an operator. Foot pedal control unit  84  may further include a housing  89 , a movable member  88 , and a pneumatic valve  90 . Foot pedal unit  84  is connected to an air pump  82  via a conduit  86 . Air pump  82  supplies pressurized air at a predetermined pressure through conduit  86  to pneumatic valve  90 . Foot pedal unit  84  is further operatively coupled to a conduit  92  that extends to a pneumatic valve  96  that is further coupled to a pneumatically controlled dental implement  98 . Further, a pneumatic switch  94  or a pressure sensor  94 ′ may be operatively coupled to conduit  92 . The switch  94  or pressure sensor  94 ′ may transmit a signal to I/O interface  68  that is measured or read by CPU  62 .  
      When a foot  87  of an operator displaces movable member  88 , pneumatic valve  90  may open to propagate pressurized air from air pump  82  to pneumatic valve  96  for driving dental implement  98 . Valve  96  only opens when an operator removes dental implement  98  from a holding fixture. The inventor herein has recognized that foot pedal control unit  84  may be further utilized to control a plurality of other devices. When at least partial displacement of movable member  88  opens or partially opens pneumatic valve  90 , pneumatic switch  94  may detect the opening and generate a signal. The signal induces CPU  62  to generate a “device actuation message.” Alternately, when a pressure sensor  94 ′ is utilized which generates a pressure signal indicative of the pressure in conduit  92 , CPU  62  may generate the “device actuation message” when the pressure is greater than or equal to a predetermined pressure. It should be noted that the pressure in conduit  92  will be greater than or equal to the predetermined pressure displacement of movable member  88  at least partially opens valve  90 . After generating the “device actuation message”, CPU  62  may induce transceiver  70  to transmit an RF signal containing the “device actuation message” to a device actuation unit.  
      An advantage of foot pedal control unit  84  is that a single movable member  88  (on a single foot pedal unit) can be utilized to selectively control a plurality of device actuation units and associated devices coupled to the device actuation units. Thus, other foot pedal units having a plurality of movable members or pedals for controlling a plurality of devices are no longer needed. Thus, with foot pedal control unit  84 , dental or medical professionals will not have to “search” for the correct pedal from a plurality of pedals with their feet to actuate a desired device, as done with other foot pedal units having a plurality of foot pedals. Further, a plurality of other foot pedal units each having a pedal for controlling a distinct device will no longer be needed. Thus, because foot pedal control unit  84  can replace a plurality of other foot pedal units, unit  84  will provide for a less cluttered operatory floor. Further, dental or medical professionals using foot pedal unit  84  can obtain a consistent “feel” or depression force for controlling multiple devices.  
      Referring to  FIG. 9 , the “device actuation message” transmitted in an RF signal from the foot pedal control system  16  may contain the following attributes: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) Actuation Code, and (v) Checksum. The Checksum value may be determined by adding the Device Actuation Unit ID and the Actuation Code. For example, foot pedal control system  14  may transmit device actuation message”  178  to device actuation unit  16  to control device  19 .  
      Referring to  FIG. 4 , device actuation unit  16  will now be described in further detail. Device actuation unit  16  is provided to actuate a device, such as a dental or medical device for example, operatively coupled to unit  16 . As shown, device actuation unit  16  may include a CPU  110 , ROM  112 , RAM  114 , I/O interface  116 , a transceiver  118 , an antenna  120 , a training mode switch  128 , Device Actuation ID DIP switch  130 , LEDs  122 ,  124 , a voltage driver  126 , and a relay  132 . CPU  110  of device actuation unit  16  may be operably coupled to a battery (not shown) for supplying an operational voltage to CPU  110 . An advantage of using device actuation unit  16  is that unit  16  can be moved with an operably coupled device to be controlled, from a first room to a second room, without the need for moving foot pedal control system  14 . Thereafter, device actuation unit  16  could be programmed to respond to another hand-held unit and another foot pedal control system  14  in the second room. Thus, device actuation unit  16  prevents contamination of other devices by allowing an operator to move device actuation  16  and an operably coupled device without having to move or touch a potentially contaminated foot pedal control system  16 . Another advantage of device actuation unit  16  is that device actuation unit  16  can be controlled using “wireless” communications thus eliminating any need for a plurality of communication wires to device actuation unit  16 .  
      Transceiver  118  is provided to transmit and receive RF signals via antenna  120 . Thus, transceiver  118  operates as both an RF transmitter and an RF receiver. Transceiver  118  may receive and transmit RF signals in one or more frequency ranges (e.g., UHF, VHF, or microwave frequency). Further, transceiver  118  may modulate an RF signal containing a message using one or more modulation techniques (e.g., amplitude modulation (AM), frequency modulation (FM), frequency shift keying (FSK)) used by those skilled in the art. Further, transceiver  118  may transmit or pulse each RF signal for a predetermined time interval, such as 15 milliseconds for example. In an alternate embodiment, transceiver  118  could be replaced with an infrared transceiver (or infrared transmitter and/or infrared receiver) configured to transmit and receive infrared signals or near-infrared signals. In another alternate embodiment, transceiver  118  could be replaced with a magnetic transceiver (or magnetic transmitter and/or magnetic receiver) configured to transmit and receive magnetic signals. In the illustrated embodiment, transceiver  118  may receive an RF signal containing a predetermined message and transmit a sequence of binary numbers representing the message to CPU  110 . It should be noted that transceiver  118  could be replaced with a single RF transmitter if “handshaking” communication is not desired between device actuation unit  16  and handheld unit  12 .  
      Voltage driver  126  is provided to generate a voltage for actuating a relay  132  coupled to device  19 . In particular, voltage driver  126  is coupled to I/O interface  126  and is further coupled to a coil  134  of relay  132 . Voltage driver  126  may receive a signal from CPU  110  via I/O interface  116  that induces driver  126  to generate a voltage sufficient to energize coil  134 . In response, a contact  136  of relay  132  may move to a closed operating position to “turn on” or energize device  19 .  
      DIP switch  130  is used to specify a Device Actuation Unit ID for device actuation unit  16 . In particular, CPU  110  reads the 8-bit number designated by switch  130  to determine the Device Actuation Unit ID and then stores the 8-bit number in ROM  112 . For example, referring to  FIG. 4 , CPU  110  can read the value “00000001” designated by selector switch  130  and then store the value “00000001” in ROM  112 .  
      LED  124  may be provided to indicate when device actuation unit  16  is receiving an RF signal having a valid “device actuation message” from foot pedal control system  14 . In particular, CPU  110  induces LED  124  to emit light when transceiver  118  is receiving an RF signal having a valid “device actuation message” from foot pedal control system  14 .  
      LED  122  may be provided to indicate when device actuation unit  16  receives a valid “device selection message” from handheld unit  12 . In particular, CPU  110  induces LED  122  to emit light when transceiver  118  receives an RF signal having a valid “device selection” message from handheld unit  12 .  
      Training mode switch  128  is provided to place CPU  110  into a “training mode” operation. In particular, when an operator closes switch  128 , CPU  110  enters a “training mode” and awaits receipt of a “training mode message” from handheld unit  12 . Referring to  FIGS. 7A, 7B , when CPU  110  receives a valid “training mode message” (e.g. training mode message  170 ), the CPU  110  generates an acknowledgment message (e.g. acknowledgment message  172 ). The “acknowledgment message” contains the following attributes: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) Device Actuation Unit ID, and (v) Checksum. The Checksum value in the “acknowledgment message” is equal to twice the Device Actuation Unit ID value. Further, CPU  110  induces transceiver  118  to transmit an RF signal containing the “acknowledgment message” to handheld unit  12 . CPU  110  also stores the Handheld ID from the valid “training mode message” in ROM  112  for verifying whether subsequent received messages are valid “device selection messages.” 
      After device actuation unit  16  has been trained with a Handheld ID and the training mode switch  128  is moved to an open operating position, CPU  110  enters a “device actuation message receiving mode.” In particular, when an operator opens switch  128 , CPU  110  awaits an RF signal containing a “device actuation message” from foot pedal control system  14 . Referring to  FIG. 9 , when a valid “device actuation message” is received by CPU  110  indicating that foot pedal control system  14  is instructing device actuation unit  16  to actuate device  19 , CPU  110  induces voltage driver  126  to close contact  136  to “turn on” or energize device  19 . Thereafter, CPU  110  continues to energize device  19  so long as a valid “device actuation message” is received from system  14  within predetermined time intervals. It should be further noted that contact  126  could also be utilized to control energization and de-energization of a pneumatic valve (not shown) or a hydraulic valve (not shown) for opening or closing a pneumatic valve or hydraulic valve, respectively, for further controlling operation of any pneumatically controlled device or hydraulically controlled device, respectively.  
      Referring to  FIG. 1 , devices  19 ,  20 ,  22  may comprise any electrically, pneumatically, magnetically, or hydraulically actuated device. For example, devices  19 ,  20 ,  22  may comprise electrically, pneumatically, magnetically, or hydraulically actuated medical or dental devices. Further, devices  19 ,  20 ,  22  may comprise one or more of the following devices: a drill, a dental chair whose chair position can be adjusted automatically, an infrared photo-optic imaging camera, a dental irrigator, an intra-oral camera, a laser, an air-abrasion unit, an electro-surgery unit, an ultrasonic teeth cleaning unit, a piezo-ultrasonic unit, an air polishing prophylaxis device, a gum depth measurement probe, a surgical microscope, a microprocessor controlled anesthetic delivery system, and an endodontic heat source device.  
      For example, a drill useable with the inventive control system includes the torque control motor drill sold under the trademark Tecnika and is manufactured by Advanced Technology Research (ATR), located at Via del Pescino, 6, 51100 Pistoia, Italy, and sold in the United States by Dentsply Tulsa Dental at 5001 E. 68 th , Tulsa, Okla. 74136-3332. Further, it should be noted that the inventive control system could be used to control operation of any electrically controlled or pneumatically controlled drill.  
      For example, a dental chair usable with the inventive control system includes the dental chair sold under the trademark Priority® manufactured by A-DEC located at 2601 Crestview Drive, Newberg, Oreg., which provides elevational control of the chair, tilting of the back of the chair, and memory recall positions. Thus, the elevation position, tilting position, and other variable position adjustments could be controlled by the inventive control system. Further, it should be noted that the inventive control system could be used to control operation of any electrically controlled or hydraulically controlled dental chair or control unit associated with the dental chair.  
      For example, an infrared photo-optic imaging camera that may be utilized with the inventive control system includes a camera sold under the trademark CEREC® manufactured by Sirona Dental Systems located at Fabrikstrabe 31, 64625 Bensheim, Hessen, Germany, and sold in the United States by Patterson Dental Supply, Inc., located at 1031 Mendota Heights Rd., Saint Paul, Minn. 55120. Further, it should be noted that the inventive control system could be used to control any imaging camera that can be automatically or externally controlled to generate a digital image or a film image.  
      For example, a dental irrigator that may be utilized with the inventive control system includes a dental irrigator sold under the trademark Piezon® Master 600, manufactured by Electro Medical Systems located at 12092 Forestgate Drive, Dallas Tex., 75243. Further, it should be noted that the inventive control system could be used to control operation of any dental irrigator or dental irrigator control system that directs fluid under pressure therethrough.  
      For example, an intra-oral camera that may be utilized with the inventive control system includes an intra-oral camera sold under the trademark Prism™, manufactured by Professional Dental Technologies, Inc.; located at 2410 Harrison Street, Batesville, Ark. 72501, or the AcuCam® Concept IV manufactured by Gendex, a division of Dentsply International located at 901 W. Oakton St., Des Plains, Ill. 60018-1884. Further, it should be noted that the inventive control system could be used to control operation of any intra-oral camera (or video capture card or video capture computer associated with the camera) to generate, store, retrieve, display, or print a digital or analog video image.  
      For example, a laser unit that may be utilized with the inventive control system includes a laser sold under the trademark Odyssey™, manufactured by Ivoclar Vivadent Inc., located at 175 Pineview Drive, Amherst, N.Y. 14228. Alternately, the system could be utilized with a laser sold under the trademark Waterlase®, manufactured by Biolase Technology, Inc., located at 981 Calle Amanecer, San Clemente, Calif. 92673. Further, it should be noted that the inventive control system could be used to control operation of any other known laser.  
      For example, an air-abrasion unit that may be utilized with the inventive control system includes an air-abrasion unit sold under the trademark PrepStart™, manufactured by Danville Engineering, located at 2021 Omega Road, San Ramon Calif. 94583. Further, it should be noted that the inventive control system could be used to control operation of any other type of air-abrasion unit utilized in dental procedures, in medical procedures, or during processing or cleaning of manufactured goods.  
      For example, an electro-surgery unit that may be utilized with the inventive control system includes the electro-surgery unit sold under the trademark Hyfrecator® 2000, manufactured by ConMed™ Corporation, located at 310 Broad Street, Utica, N.Y. 13501. Further, it should be noted that the inventive control system could be used to control operation of any other electro-surgery unit that utilizes electrical energy for removing tissue or bone.  
      For example, an ultrasonic teeth cleaning unit that may be utilized with the inventive control system includes the teeth cleaning unit sold under the trademark Cavitron® 3000 manufactured by Dentsply International located at 901 W. Oakton Street, Des Plains, Ill. 60018-1884. Further, it should be noted that the inventive control system could be used to control operation of any other ultrasonic teeth cleaning unit.  
      For example, a piezo-ultrasonic unit that may be utilized with the inventive control system includes the piezo-ultrasonic unit sold under the trademark Spartan MTS™, manufactured by Obtura Spartan located at 1663 Fenton Business Park Court, Fenton, Mo. 63026. Further, it should be noted that the inventive control system could be used to control operation of any other piezo-ultrasonic unit that agitates or vibrates a tip for cleaning teeth or removing tooth structure. Piezo-ultrasonic units may have fluid cooled tips.  
      For example, an air polishing prophylaxis device that may be utilized with the inventive control system includes the air polishing prophylaxis device sold under the trademark Cavitron® Prophy-Jet®, manufactured by Dentsply International located at 901 W. Oakton Street, Des Plains, Ill. 60018-1884. Further, it should be noted that the inventive control system could be used to control operation of any other air polishing prophylaxis device that uses compressed air for delivering a fluid and/or an abrasive compound out of a nozzle for cleaning teeth and gums.  
      For example, the gum depth measurement probe that may be utilized with the inventive control system includes the gum depth measurement probe sold under the trademark Florida Probe®, manufactured by Florida Probe Corporation, located at 3700 NW 91 st  Street, Suite C-100, Gainesville, Fla. 32606. Further, it should be noted that the inventive control system could be used to control operation of any other gum depth measurement probe that can be automatically or externally controlled to take a gum depth measurement.  
      For example, a surgical microscope that may be utilized with the inventive control system includes the surgical microscope sold under the trademark OPMI® pico, manufactured by Carl Zeiss Surgical Inc., located at One Ziess Drive, Thornwood, N.Y. 10594. Alternately, the inventive control system could utilized with the surgical microscope sold under the trademark Protege™, manufactured by Global Surgical Corporation, located at 3610 Tree Court Industrial Blvd., St. Louis, Mo. 63122-6622. Further, it should be noted that the inventive control system could be used to control operation of any other surgical microscope that includes one or more of: automatically controllable height adjustment, automatically controllable focusing, automatically controllable field of view size, viewing lights, and a camera associated with the surgical microscope.  
      For example, a microprocessor-controlled anesthetic delivery system that may be utilized with the inventive control system includes the anesthetic delivery system sold under the trademark The Wand™ II, manufactured by the Dental Division of Milestone Scientific located at 151 S. Pfingsten Road, Deerfield, Ill. 60015. Further, it should be noted that the inventive control system could be used to control operation of any other microprocessor-controlled anesthetic delivery system that delivers predetermined amounts of an anesthetic to a medical or dental patient.  
      For example, an endodontic heat source device that may be utilized with the inventive control system includes the endodontic heat source device sold under the trademark System B HeatSource™ model 1005, manufactured by Analytic-Sybron Dental Specialties located at 1332 South Lone Hill Avenue, Glendora, Calif. 91740. Further, it should be noted that the inventive control system could be used to control operation of any other endodontic heat source device.  
      Referring to  FIG. 4 , although device  19  could comprise any one of the foregoing plurality of described devices, for purposes of discussion, device  19  will comprise an electrically actuated drill. Drill  19  may include a motor  140  electrically coupled to a low-voltage source  142  and electrical contact  136 . Upon closure of electrical contact  136 , voltage source  142  energizes motor  140  to rotate or reciprocate a drill bit (not shown) or a root canal file.  
      Referring to  FIG. 11A , a method  190  for transmitting a Handheld Unit ID from handheld unit  12  to device actuation unit  19  will now be described. At step  192 , an operator of handheld unit  12  closes training mode switch  46  on handheld unit  12  to induce unit  12  to enter “training mode.” 
      At step  194 , CPU  30  in handheld unit  12  energizes LED  56 .  
      At step  196 , the operator closes device selection switch  40  on handheld unit  12  having an associated Device Actuation Unit ID Number (e.g., “00000001”).  
      At step  198 , in response to the closure of switch  40 , CPU  30  induces RF transceiver  38  to transmit an RF signal having a “training mode message” including: (i) Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) Training Mode Code, and (v) Checksum.  
      At step  200 , RF transceiver  118  in device actuation unit  16  receives the RF signal having the “training mode message.” 
      At step  202 , CPU  110  in unit  16  determines whether the received “training mode message” is a valid message. If the value of step  202  equals “yes”, the method advances to step  204 . Otherwise, the method  190  is exited.  
      At step  204 , CPU  110  stores the received Handheld ID in ROM  112 .  
      At step  206 , CPU  110  induces RF transceiver  118  to transmit an RF signal having an “acknowledgment message” including: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) Device Actuation Unit ID, and (v) Checksum.  
      At step  208 , RF transceiver  38  in handheld unit  12  receives the RF signal having the “acknowledgment message” from device actuation unit  16 .  
      At step  210 , CPU  30  in handheld unit  12  makes a determination as to whether the received “acknowledgment message” was a valid acknowledgment message. If the value of step  210  equals “yes”, the method advances to step  212 . Otherwise, the method returns to step  202 .  
      At step  212 , CPU  30  in handheld unit  12  energizes LED  48  indicating that (i) the Device Actuation Unit ID associated with switch  40  (and stored in ROM  32 ) matches the Device Actuation Unit ID selected by DIP switch  130  of device actuation unit  16 , and (ii) unit  16  stored the Handheld ID contained in the received “training mode message.” After step  212 , the method  190  is exited.  
      Referring to  FIG. 1B , the method  213  for implementing step  202  for determining whether a valid “training mode message” was received by device actuation unit  16  will now be explained. In particular, step  202  may be implemented using the steps  214 - 224 . At step  214 , CPU  110  makes a determination as to whether a Device Actuation Unit ID stored in ROM  112  equals the Device Actuation Unit ID contained in the received “training mode message”. If the value of step  214  equals “yes”, the method advances to step  216 . Otherwise, the method advances to step  224  that indicates an invalid “training mode message” was received.  
      At step  216 , CPU  110  makes a determination as to whether a Training Mode Code stored in ROM  112  equals the Training Mode Code contained in the received “training mode message.” If the value of step  216  equals “yes”, the method advances to step  218 . Otherwise, the method advances to step  224   
      At step  218 , CPU  110  makes a determination as to whether the number of bytes of the transmitted message equals the Message Length value contained in the received “training mode message.” 
      If the value of step  216  equals “yes”, the method advances to step  220 . Otherwise, the method advances to step  224 .  
      At step  220 , CPU  110  makes a determination as to whether the checksum calculated from the received “training mode message” equals the Checksum value contained in the received “training mode message.” If the value of step  220  equals “yes”, CPU  110  indicates that a valid “training mode message was received. In particular, CPU  110  may set a internal memory flag equal to a logical “1” value. Otherwise, the method advances to step  224  where CPU  110  indicates that an invalid “training mode message” was received.  
      Referring to  FIG. 11C , the method  225  for implementing step  210  for determining whether a valid “acknowledgment message” was received by handheld unit  12  from device actuation unit  16  will now be explained. At step  226 , CPU  30  in handheld unit  12  makes a determination as to whether a Handheld ID stored in ROM  32  equals the Handheld ID contained in the received “acknowledgment message.” If the value of step  226  equals “yes”, the method advances to step  228 . Otherwise, the method advances to step  236  that indicates an invalid “acknowledgment message” was received by handheld unit  12 .  
      At step  228 , CPU  30  makes a determination as to whether a Device Actuation Unit ID stored in ROM  32  equals the Device Actuation Unit ID contained in the received “acknowledgment message”. If the value of step  228  equals “yes”, the method advances to step  230 . Otherwise, the method advances to step  236 .  
      At step  230 , CPU  30  makes a determination as to whether the number of bytes of the transmitted in the “acknowledgment message” equals the Message Length value contained in the received “acknowledgment message.” If the value of step  230  equals “yes”, the method advances to step  232 . Otherwise, the method advances to step  236 .  
      At step  232 , CPU  30  makes a determination as to whether the checksum calculated by CPU  30  based on the received “acknowledgment message” equals the Checksum value contained in the “acknowledgment message.” If the value of step  232  equals “yes”, CPU  30  indicates that a valid “acknowledgment message” was received. In particular, CPU  30  may set a internal memory flag equal to a logical “1” value. Otherwise, the method advances to step  236  where CPU  30  indicates that an invalid “acknowledgment message” was received.  
      Referring to  FIG. 12A , a method for transmitting a Device Actuation Unit ID from handheld unit  12  to foot pedal control system  14  will now be explained. In other words, the method for selecting a device to be controlled by foot pedal control system  14  will be explained. At step  248 , an operator opens “training mode” switch  46  on handheld unit  12  to induce CPU  30  to enter into a “device selection mode” operation.  
      At step  250 , CPU  30  de-energizes LED&#39;s  48 ,  50 ,  52 ,  54 ,  56 .  
      At step  252 , an operator closes device selection switch  40  on handheld unit  12  having associated Device Actuation Unit ID number (e.g., “00000001”). At step  254 , in response to the closure of switch  40 , CPU  30  induces RF transceiver  38  to transmit an RF signal having a “device selection message” including: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, and (v) Checksum. The Checksum value in the “device selection message” is identical to the Device Actuation Unit ID. For example, transceiver  38  could transmit an RF signal having device selection message  174 .  
      At step  256 , RF transceiver  70  in foot pedal control system  14  receives the RF signal having the “device selection message” from handheld unit  12 .  
      At step  258 , CPU  62  in foot pedal control system  14  makes a determination as to whether the “device selection message” was a valid message. If the value of step  258  equals “yes”, the method advances to step  260 . Otherwise, the method  246  is exited.  
      At step  260 , CPU  62  stores the received Device Actuation Unit ID from the “device selection message” in ROM  64 .  
      At step  262 , CPU  62  induces RF transceiver  70  to transmit an RF signal having an “acknowledgment message” including: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) Device Actuation Unit ID, and (v) Checksum. For example, transceiver  70  could transmit an RF signal having “acknowledgement message”  176 .  
      At step  264 , RF transceiver  38  in handheld unit  12  receives the RF signal having the “acknowledgment message” from unit  14 .  
      At step  265 , CPU  30  in handheld unit  12  makes determination as to whether a valid “acknowledgment message” was received. It should be noted that step  265  may be implemented using the method  225  of  FIG. 11C . If the value of step  265  equals “yes”, the method advances to step  266 . Otherwise, the method  246  is exited.  
      At step  266 , CPU  30  in handheld unit  12  energizes LED  48  indicating that foot pedal controls system  14  has “learned” the Device Actuation Unit ID associated with switch  40  of handheld unit  12 . After step  266 , the method  246  is exited.  
      Referring to  FIG. 12B , the method  267  for implementing step  258  for determining whether a valid “device selection message” was received by foot pedal control system  14  from handheld unit  12  will now be explained. At step  268 , CPU  62  in foot pedal control system  14  makes a determination as to whether a Handheld ID stored in ROM  64  equals the Handheld ID contained in the “device selection message.” If the value of step  268  equals “yes”, the method advances to step  270 . Otherwise, the method advances to step  276  that indicates an invalid “device selection message” was received by foot pedal control system  14 .  
      At step  270 , CPU  62  makes a determination as to whether the number of bytes of the transmitted “device selection message” equals the Message Length value contained in the “device selection message.” If the value of step  270  equals “yes”, the method advances to step  272 . Otherwise, the method advances to step  276 .  
      At step  272 , CPU  62  makes a determination as to whether the checksum calculated from the received “device selection message” equals the Checksum value contained in the “device selection message.” If the value of step  272  equals “yes”, CPU  62  indicates that a valid “device selection message” was received. In particular, CPU  62  may set a internal memory flag equal to a logical “1” value. Otherwise, the method advances to step  276  where CPU  62  indicates that an invalid “device selection message” was received.  
      Referring to  FIG. 13A , a method  286  for transmitting a “device actuation message” from foot pedal control system  14  to device actuation unit  16  will now be explained.  
      At step  288 , an operator&#39;s foot  87  at least partially displaces a movable member on foot pedal unit  84 .  
      At step  290 , CPU  62  detects the displacement of the movable member. It should be noted that several methods may be utilized to detect displacement of a movable member on a foot pedal unit. For example, referring to  FIG. 3 , CPU  62  may detect closure of a pneumatic switch (e.g. pneumatic switch  94 ) operably coupled to conduit  92  downstream of foot pedal unit  84 . Closure of the pneumatic switch  94  would indicate that movable member  88  has been at least partially displaced by an operator.  
      Alternately, CPU  62  may received a signal (P) from a pressure sensor  94 ′ operably coupled to conduit  92 . When CPU  62  determines that the pressure signal indicates a pressure in conduit  92  greater than a predetermined pressure level, CPU  62  can determine that a movable member  88  has been at least partially displaced by an operator.  
      Alternately, referring to  FIGS. 5 and 6 , foot pedal unit  84  may be replaced with either a foot pedal unit  144  or a foot pedal unit  158 . As shown, foot pedal unit  144  includes a housing  144 , a movable member  150 , and an electrical switch  146  operably coupled to movable member  150 . Partial rotational displacement of movable member  150  closes electrical contact  146  which may be detected by CPU  62 . Similarly, foot pedal unit  152  includes a housing  154 , a movable member  156 , and an electrical switch  158  operably coupled to movable member  156 . Partial linear displacement of movable member  156  closes electrical switch  158  which may be detected by CPU  62 .  
      Referring to again to  FIG. 13A , at step  292 , in response to displacement of the movable member, CPU  62  induces transceiver  70  to transmit an RF signal having a “device actuation message” including: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) Actuation Code, and (v) Checksum. The Checksum value may be determined by adding together the Device Actuation Unit ID and the Actuation Code. For example, transceiver  70  may transmit a “device selection message”  178 .  
      At step  294 , RF transceiver  118  in device actuation unit  16  receives the RF signal having the “device actuation message” from foot pedal control system  14 .  
      At step  296 , CPU  110  in device actuation unit  16  makes a determination as to whether the “device actuation message” is a valid message. If the value of step  296  equals “yes”, the method advances to step  298 . Otherwise, the method advances to step  302 .  
      At step  298 , CPU  110  in device actuation unit  16  actuates (e.g., turns on) or continues to actuate device  19  operably coupled to device actuation unit  16 . In particular, CPU  110  can induce voltage driver  126  to close relay  132  to “turn on” or energize motor  140  of device  19 .  
      At step  300 , CPU  110  starts a timer T 1  or continues a timer T 1 .  
      At step  302 , CPU determines whether the timer value associated with timer T 1  is greater than a threshold time T Threshold . If the value of step  302  equals “yes”, the method advances to step  304 . Otherwise, the method returns to step  290 .  
      At step  304 , CPU  110  induces voltage driver  126  to de-actuate device  19 . In particular, CPU  110  can induce voltage driver  126  to open relay  132  to “turn off” or de-energize motor  140  of device  19 . After step  306 , method  286  is exited.  
      Referring to  FIG. 13B , a method  307  for implementing step  296  for determining whether a valid “device actuation message” was received by device actuation unit  16  from foot pedal control system  14  will now be explained. At step  308 , CPU  110  in device actuation unit  16  makes a determination as to whether a Handheld ID stored in ROM  112  equals the Handheld ID contained in the “device actuation message.” If the value of step  308  equals “yes”, the method advances to step  310 . Otherwise, the method advances to step  320  that indicates an invalid “device selection message” was received by device actuation unit  16 .  
      At step  310 , CPU  110  makes a determination as to whether a Device Actuation Unit ID stored in ROM  112  equals the Device Actuation Unit ID contained in the “device actuation message”. If the value of step  310  equals “yes”, the method advances to step  312 . Otherwise, the method advances to step  320 .  
      At step  312 , CPU  110  makes a determination as to whether the number of bytes of the transmitted “device actuation message” equals the Message Length value contained in the “device actuation message.” If the value of step  312  equals “yes”, the method advances to step  314 . Otherwise, the method advances to step  320 .  
      At step  314 , CPU  110  makes a determination as to whether a checksum calculated from the received “device actuation message” equals the Checksum value contained in the “device actuation message.” If the value of step  314  equals “yes”, the method advances to step  316 . Otherwise, the method advances to step  320 .  
      At step  316 , CPU  110  takes determination as to whether an actuation code stored in ROM  112  equals the Actuation Code contained in the “device actuation message.” If the value of step equals “yes”, CPU  110  indicates a valid “device actuation message” was received. In particular, CPU  110  may set an internal memory flag equal to a logical “1” value. Otherwise, the method advances to step  320  where CPU  110  indicates that an invalid “device actuation message” was received.  
      Referring to  FIG. 14 , a second exemplary embodiment of a foot pedal control system (e.g., foot pedal control system  14 ′) is illustrated. The primary difference between foot pedal control systems  14  and  14 ′, is that system  14  generates a “device actuation message” for “turning-on” or actuating a device, where system  14 ′ generates a variable “device actuation message” for varying either (i) a speed of a device, such as a drill speed for example, (ii) a position of a member of the device, or (iii) an operational intensity of the device, such as an operational intensity of a laser for example.  
      Foot pedal control system  14 ′ may include CPU  62 ′, ROM  64 , RAM  66 , I/O interface  68 , transceiver  70 , antenna  71 , LEDs  72 ,  74 ,  76 ,  78 , a Handheld ID DIP switch  80 , and a foot pedal unit  340 .  
      Foot pedal unit  340  includes a housing  342 , a movable member  344 , and a position sensor  346  operably coupled to movable member  344 . Position sensor  346  generates a signal (POS 1 ) indicative of an angular position of movable member  344 . CPU  62 ′ may receive signal (POS 1 ) and generate a variable “device actuation message” responsive thereto. In an alternate embodiment of foot pedal control system  14 ′, foot pedal unit  340  could be replaced by foot pedal unit  348  (shown in  FIG. 15 ) that includes a housing  350 , a movable member  352 , a position sensor  356 , and a magnet  354 . When depressed, movable member  352  can move linearly within housing  350 . Movable member  352  may have a magnet  354  coupled thereto. Position sensor  356  may comprise a Hall Effect Sensor that detects the linear displacement (d) of magnet  354  and of movable member  352 , and generates a signal (POS 2 ) responsive thereto. CPU  62 ′ may receive signal (POS 2 ) and generate a variable “device actuation message” responsive thereto.  
      Referring to  FIGS. 10 and 14 , CPU  62 ′ may generate a variable “device actuation message” having the following attributes: (i) Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) a Variable Actuation Code, (v) a Command Code, (vi) Checksum. The Variable Actuation Code may be a unique number for instructing device actuation unit  16 ′ that variable control of device  351  is desired. The Command Code corresponds to a computed variable value that can be utilized by device actuation unit  16 ′ for varying the operational speed, operational position, or operational intensity of a device. In particular, the value of the Command Code may be increased as the angular displacement of movable member  344  (or the linear displacement of the member  352 ) from a non-depressed position increases. Similarly, the value of the Command Code may be decreased as the angular displacement of movable member  344  (or the linear displacement of the member  352 ) from a non-depressed position decreases. The Checksum value may be determined by adding together the Device Actuation Unit ID, the Variable Actuation Code, and the Command Code.  
      Referring to  FIG. 16 , a second exemplary embodiment of a device actuation unit (e.g., device actuation unit  16 ′) is illustrated. The primary difference between device actuation units  16  and  16 ′ is that unit  16  “turns on” a device whereas unit  16  can variably control the operation of a device. For example, unit  16 ′ can control the operational speed, operational position, or operational intensity of a device operably coupled to unit  16 ′.  
      As shown, device actuation unit  16 ′ may include a pulse width modulation (PWM) driver  352  operably coupled to I/O interface  116 . CPU  110 ′ can induce PWM driver  352  to generate a PWM signal that can control the speed of a motor  356  of device  351  based upon a value of the Command Code in a received variable “device actuation message.” It should be noted that device actuation unit  16 ′ could be utilized to control any device which can be variably controlled. For example, device actuation unit  16 ′ could be utilized to variably control: (i) a laser, (ii) a pneumatically or electrically actuated drill, (iii) a surgical microscope that can be automatically controlled, as discussed above, (iv) a microprocessor controlled anesthetic delivery system, as discussed above. It should be noted that PWM driver  352  could be replaced with any other type of known variable current driver or voltage driver for variably controlling a device. It should be further noted that PWM driver  352  (or an alternate variable current drive or voltage driver) could also be utilized to control a pneumatic valve (not shown) or a hydraulic valve (not shown) for further controlling operation of any pneumatically controlled device or hydraulically controlled device.  
      Referring to  FIG. 17 , a method  358  for transmitting a variable “device actuation message” from foot pedal control system  14 ′ to device actuation unit  16 ′ will now be described.  
      At step  360 , an operator of foot pedal control system  14 ′ at least partially displaces the movable member  344  on foot pedal unit  340 .  
      At step  362 , CPU  62 ′ determines an amount displacement of the movable member  344 . As discussed above, CPU  62 ′ may determine an amount of angular displacement of movable member  344 , or alternately determine an amount of linear displacement of movable member  352 .  
      At step  364 , in response to displacement of movable member  344 , CPU  62 ′ induces transceiver  70  to transmit an RF signal having a variable “device actuation message” including: (i) a Handheld ID, (ii) Message Length, (iii) Device Actuation Unit ID, (iv) Variable Actuation Code, (v) Command Code, and (vi) Checksum. For example, transceiver  70  could transmit an RF signal having “device actuation message”  180 .  
      At step  366 , RF transceiver  118  in device actuation unit  16 ′ receives the RF signal having the variable “device actuation message.” 
      At step  368 , CPU  110 ′ in device actuation unit  16 ′ makes a determination as to whether the variable “device actuation message” is a valid message. If the value of step  368  equals “yes”, the method advances to step  370 . Otherwise, the method advances to step  374 .  
      At step  370 , CPU  110 ′ induces PWM driver  352  to generate PWM control signals to control operation of a device (e.g., device  20 ) coupled to unit  16 ′ based on the Command Code in the variable “device actuation message.” In particular, the PWM control signals can be utilized to control an operational speed, an operational position, or an operational intensity of a device.  
      At step  372 , CPU  110 ′ starts a timer T 2  or continues a timer T 2 .  
      At step  374 , CPU  110 ′ determines whether the timer value associated with timer T 2  is greater than a threshold time T Threshold . If the value of step  374  equals “yes”, the method advances to step  376 . Otherwise, the method returns to step  362 .  
      At step  376 , CPU  110 ′ induces PWM driver  352  to de-actuate or de-energize device  20 .  
      At step  378 , CPU  110 ′ resets the timer T 2 . After step  378 , the method  358  is exited.  
      Referring to  FIG. 18 , a video image capture system  400  is illustrated that may be controlled by device actuation unit  16 . Video image capture system  400  includes a CPU  402 , a ROM  404 , a RAM  406 , an I/O interface  408 , a video capture card/circuit  410 , and an intra-oral camera  416 .  
      Video capture card  410  is provided to generate, store, retrieve, display, or print a digital or analog video image from a (VIDEO-IN) signal received from an intra-oral camera  416 . For example, video capture card  410  may comprise a video capture card sold under the trademark ADVC-50 A/D Converter, manufactured by Canopus Corporation of 711 Charcot Avenue, San Jose, Calif. 95131. Alternately, for example, video capture card  410  may comprise a video capture card sold under the trademark DVRaptor, manufactured by Canopus Corporation. Alternately, for example, video&#39;capture card  410  may comprise a video capture card sold under the trademark DVRaptor, manufactured by Canopus Corporation. Video capture card  410  may be induced to store a video image to a memory (not shown) when first and second electrical terminals (not shown) on card  410  coupled to electrical lines  412 ,  414 , respectively, are electrically coupled together. Thereafter, video capture card  410  may transfer the digital or analog video image through I/O interface  408  to CPU  402  that may store the digital or analog video image in ROM  404  or RAM  406 . CPU  402  may further display the digital or analog video image on a computer monitor (not shown) operably coupled to CPU  402 .  
      Thus, when device actuation unit  16  receives a valid “device actuation message” from foot pedal control system  14 , unit  16  can close contact  136 . In response, video capture card  410  can store the image to an internal memory and also transfer the digital image to CPU  402 . As discussed, CPU  402  can store the digital image in ROM  404  or RAM  406  and can display the image on a computer monitor.  
      The inventive system the method for remotely controlling devices provides a substantial advantage over other systems and methods. In particular, the system and method provide a foot pedal unit having one movable member that can be utilized to control multiple devices. Thus, an operator of the foot pedal unit can obtain a consistent control of multiple devices. Further, the single foot pedal unit can replace a plurality of other foot pedal units providing for a substantially less cluttered operatory floor.