Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This invention is related to U.S. patent application Ser. No. (Attorney Docket No. 2030.68), entitled “Transmitter Adaptable for Left-Handed or Right-Handed Use” (Inventors: Joel Carter, Bill Yeung, and Chan Yeung) and U.S. patent application Ser. No. (Attorney Docket No. 2030.69), entitled “Radio Frequency Toy Controller Design” (Inventor: Chan Yeung), both of which were filed on the same day as the present application. 
     
    
     BACKGROUND  
       [0002]     This disclosure relates generally to radio-controlled mobile toys and, more specifically, to selecting an operating frequency in such toys.  
         [0003]     A radio-controlled toy, such as a radio-controlled car, is generally operated by a transmitter that transmits radio signals to the radio-controlled car using a predefined frequency (e.g., a channel). Because the radio-controlled car needs to be able to receive the radio signals transmitted by the transmitter, both the transmitter and the radio-controlled car should be set to a common frequency (e.g., should use the same channel).  
         [0004]     Current methods for setting the frequency of the transmitter and the radio-controlled car include the use of crystals or radio frequency (RF) modules, which typically have a predetermined frequency. Accordingly, in order to operate the radio-controlled car via another frequency, the crystals or RF modules in both the transmitter and radio-controlled car must be replaced with new ones of the desired frequency, which can be both time-consuming and expensive.  
         [0005]     Therefore, what is needed is a transmitter having a channel selector for selecting an operating frequency of the transmitter and an associated radio-controlled toy.  
       SUMMARY  
       [0006]     Provided is a channel selector for selecting an operating frequency. In one embodiment, a transmitter is provided for enabling the selection of one of a plurality of predefined channels for use in communicating with a radio-controlled toy. The transmitter includes a selector for selecting one of the plurality of channels, a detector for identifying the selected channel, and an interface for transferring the identified channel from the transmitter to the toy.  
         [0007]     In another embodiment, a programmable frequency radio-controlled car is provided. The radio-controlled car includes an interface for receiving a user-selected operating frequency from a transmitter, a controller for detecting the received operating frequency; and a memory accessible to the controller for storing the received operating frequency. The stored operating frequency is used by the radio-controlled car for interpreting signals transmitted by the transmitter.  
         [0008]     In yet another embodiment, a system for selecting an operating frequency is provided for communication between a radio transmitter and a radio-controlled toy. The radio transmitter of the system includes a frequency selector for selecting the operating frequency from a plurality of frequencies and an interface for transferring the selected operating frequency to the radio-controlled toy. The radio-controlled toy of the system includes an interface for receiving the selected operating frequency from the radio transmitter and a memory accessible to the interface for storing the received operating frequency.  
         [0009]     In yet another embodiment, a transmitter for a radio-controlled toy having a programming contact and at least two charging contacts is provided. The transmitter includes a housing, a frequency selection circuit positioned within the housing, a charging circuit positioned within the housing, an interface pad proximate to a surface of the housing, and a channel selection switch on the housing for selecting one of a plurality of predefined frequencies for the transmitter and the toy. The interface pad provides electrical communication between the frequency selection circuit and the programming contact of the toy to transfer frequency selection information from the frequency selection circuit to the toy. The interface pad further provides electrical communication between the charging circuit and the charging contacts of the toy. The selected frequency is set as an operating frequency of the transmitter and toy during charging of the toy, and the operating frequency is used for communications between the transmitter and toy. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a transmitter and a radio-controlled car according to one embodiment of the present disclosure.  
         [0011]      FIG. 2  is a front view of the transmitter of  FIG. 1 .  
         [0012]      FIG. 3  is a rear view of the transmitter of  FIG. 1 .  
         [0013]      FIG. 4  is a bottom view of the radio-controlled car of  FIG. 1 .  
         [0014]      FIG. 5A  is an exemplary circuit diagram for the transmitter of  FIG. 1  illustrating a channel selection circuit, a left hand/right hand selection circuit, and a control circuit for a microcontroller unit.  
         [0015]      FIG. 5B  is an exemplary circuit diagram for the transmitter of  FIG. 1  illustrating a forward/backward motion control circuit.  
         [0016]      FIG. 5C  is an exemplary circuit diagram for the transmitter of  FIG. 1  illustrating a left/right steering circuit.  
         [0017]      FIG. 5D  is an exemplary circuit diagram of a signal transmission circuit located in the transmitter of  FIG. 1 .  
         [0018]      FIG. 5E  is an exemplary circuit diagram of a charging circuit located in the transmitter of  FIG. 1 .  
         [0019]      FIG. 5F  is an exemplary circuit diagram of a light emitting diode (LED) circuit located in the transmitter of  FIG. 1 .  
         [0020]      FIG. 5G  is a diagram illustrating a first position of an exemplary left hand/right hand selection switch associated with the transmitter of  FIG. 1 .  
         [0021]      FIG. 5H  is a diagram illustrating a second position of the exemplary left hand/right hand selection switch of  FIG. 5G .  
         [0022]      FIG. 6A  is an exemplary circuit diagram for the radio-controlled car of  FIG. 1  illustrating a low noise amplifier, a receiver circuit, and a control circuit for a microcontroller unit.  
         [0023]      FIG. 6B  is an exemplary circuit diagram of a first motor control circuit located in the radio-controlled car of  FIG. 1 .  
         [0024]      FIG. 6C  is an exemplary circuit diagram of a second motor control circuit located in the radio-controlled car of  FIG. 1 .  
         [0025]      FIG. 6D  is an exemplary circuit diagram of a DC-DC converter circuit located in the radio-controlled car of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0026]     This disclosure relates generally to radio-controlled mobile toys and, more specifically, to selecting an operating frequency in such toys. It is understood, however, that the following disclosure provides many different embodiments or examples. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.  
         [0027]     Referring to  FIGS. 1-3 , in one embodiment, a transmitter  10  may be used to control a radio-controlled toy  12 . For purposes of example, the radio-controlled toy  12  is a radio-controlled car that includes a body  14  and a chassis  16 . The body  14  may connect to the chassis  16  in a variety of ways, including a conventional pressure fit or a snap connection. Accordingly, various configurations of the body  14  may be used with the chassis  16 . The radio-controlled car  12  further includes a set of wheels  22  associated with the chassis  16 .  
         [0028]     A plurality of electronic circuits ( FIGS. 5A-6D ) are housed within the transmitter  10  and the radio-controlled car  12 . As will be described later in greater detail, the circuits enable interaction between the transmitter  10  and the radio-controlled car  12  so that the radio-controlled car  12  may be controlled via the transmitter  10 . An antenna  18  may be provided on the radio-controlled car  12  to receive radio signals from an antenna  20  of the transmitter  10 .  
         [0029]     The transmitter  10  includes a housing  24  for enclosing the circuits. A user may interact with the circuits using a plurality of control devices disposed on the transmitter  10 . These control devices may include a power switch  26 , a channel selection switch  28 , an indicator  30 , a steering member  32 , a steering adjuster  34 , a left hand/right hand selection switch  36 , a release button  38 , and a motion control member  40 . It is understood that the number, type, and arrangement of control devices on the transmitter  10  illustrated in  FIGS. 1-3  are for purposes of example, and that alternate numbers and/or types of control devices may be provided. For example, the channel selection switch  28  may be any user input means, including but not limited to a rotatable knob, or a voice-recognition circuit. An indicator housing  42  may be used to protect the indicator  30 .  
         [0030]     As illustrated, in the present example, the power switch  26 , the channel selection switch  28 , the indicator  30 , the steering member  32 , and the release button  38  are provided on a front surface  44  of the transmitter  10 , while the steering adjuster  34  is provided on a side  46  of the transmitter  10 , and the left hand/right hand selection switch  36  is provided on a top surface  86  of the transmitter. Furthermore, the motion control member  40  extends from the transmitter  10  into a cutout  48  formed through the transmitter  10 .  
         [0031]     The steering member  32  and the motion control member  40  enable the movement of the radio-controlled car  12  to be controlled. The steering member  32  may include an annular portion  50 , which is radially spaced from a central portion  52 . The central portion  52  is the portion of the steering member  32  that extends into the housing  24  to operatively connect with a left/right steering circuit as will be described later with respect to  FIG. 5C . The steering member  32  may further include a plurality of radially-extending legs  54  for connecting the annular portion  50  with the central portion  52 . The steering member  32  may be removably connected to the transmitter  10  in any conventional manner, such as a snap-fit.  
         [0032]     The steering adjuster  34  on the transmitter  10  may be used to ensure proper wheel alignment (e.g., to correct “drift”) in the steering of the radio-controlled car  12 . For example, if the transmitter  10  is directing the radio-controlled car  12  to drive in a straight line, but the radio-controlled car  12  is veering to the right, the steering alignment may be adjusted via the steering adjuster  34  so that the radio-controlled car  12  proceeds in a straight line as directed.  
         [0033]     In the present example, the steering adjuster  34  is a wheel, which is initially in a neutral position. Rotating the steering adjuster  34  adjusts the signal that is transmitted by the transmitter  10  to the radio-controlled car  12 . For example, if the transmitter  10  transmits instructions to the radio-controlled car  12  using a series of pulses (e.g., pulse modulation), then the steering adjuster  34  may be rotated to a non-neutral position to alter the transmitted pulses so that they represent a neutral state. For example, a potentiometer responsive to the rotation of the steering adjuster  34  may be used to alter a pulse width of the transmitted pulses.  
         [0034]     The motion control member  40  may include an extension portion  68  and an inverted U-shaped portion  70 . The inverted U-shaped portion  70  provides a groove  72  through which the user may insert a finger to control movement of the motion control member  40  in a substantially right or left direction. Movement of the motion control member  40  from a neutral position instructs the transmitter  10  to signal the radio-controlled car  12  to move either forward or backward. The direction of movement may be dependent on the left hand/right hand selection switch  36 , as will be described further with respect to the operation of the radio-controlled car  12  and a left hand/right hand selection circuit of  FIG. 5A .  
         [0035]     The transmitter  10  may also include a motion control trimmer  74  ( FIG. 3 ), which may be adjustable via a tool  66  ( FIG. 2 ), such as a screwdriver. In one example, the tool  66  may be housed in the transmitter  10  during nonuse as illustrated by the exploded view of the tool in  FIG. 2 . The motion control trimmer  74  may be used to compensate for undesired forward or backward motion of the radio-controlled car  12 . For example, if the radio-controlled car  12  moves in a forward or backward direction when the motion control member  40  is in a neutral position, the motion control trimmer  74  may be adjusted so that the radio-controlled car  12  remains stationary unless the motion control member  40  is moved from its neutral position. As described previously with respect to the steering adjuster  34 , the motion control trimmer  74  may operate via a potentiometer that adjusts a characteristic of the signal transmitted to the radio-controlled car  12 .  
         [0036]     Referring now to the front surface  44  of the transmitter  10 , the cutout  48  generally defines a left portion  76 , a right portion  78 , and a middle portion  80  of the front surface. A gripping means  82  may be formed in the left portion of the front surface for providing a left-hand gripping surface for the user. The gripping means  82  may be any non-uniform surface that aids the user in gripping the transmitter  10 . For example, the gripping means  82  may be a plurality of channels formed in the transmitter. The right portion  78  of the front surface  44  protrudes relative to the left portion  76  and is generally curved to provide a right-hand gripping surface for the user. A gripping means  84  may be formed in the right portion  78  of the front surface  44  to further aid in providing the right-hand gripping surface.  
         [0037]     Referring now to the top surface  86  of the transmitter  10 , an interface pad  90  is adapted to couple the radio-controlled car  12  to the transmitter  10  during selection of an operating frequency and charging of a battery (not shown) housed within the radio-controlled car  12 . It is understood that selection of the operating frequency and charging of the battery may be accomplished independently of one another. For example, the operating frequency of the car  12  may be changed even if the car is fully charged. It is further understood that changing of the frequency may be accomplished using alternate interfaces such as via an infrared port or wirelessly using a radio frequency. For example, if the frequency is changed wirelessly using a radio frequency, the transmitter  10  and the car  12  may each include a memory or timer for monitoring a defined amount of time. At the end of the defined amount of time, the transmitter  10  and the car  12  will simultaneously switch over to the new frequency.  
         [0038]     In the present example, a pair of catches  92  and  94  extend through the interface pad  90  to couple the chassis  16  of the radio-controlled car  12  to the interface pad  90  during charging. The catches  92  and  94  may also aid in aligning the radio-controlled car  12  on the interface pad  90 . The release button  38  is operatively connected to the catches  92  and  94 , such that depression of the release button  38  releases the radio-controlled car  12  from the interface pad  90 . A portion of the top surface  86  of the transmitter  10  may be formed as a removable cover  96  for providing access to a battery housing (not shown) disposed within the transmitter.  
         [0039]     A plurality of slots  100 ,  102 , and  104  are formed in the interface pad  90  to provide external access to a pair of electrical charging contacts  106  and  108  and an electrical programming contact  110 , respectively. It is understood that the orientation of contacts extending from the transmitter  10  is variable, and that additional contacts may be used. A charging button  112  may be further provided through the interface pad  90  for contacting the chassis  16 , as will be described later with respect to the operation of the radio-controlled car  12  and a charging circuit of  FIG. 5E .  
         [0040]     A cover  114  may be used to enclose and protect the interface pad  90  and the antenna  20  during nonuse. The housing  24  includes a step-down portion  116  for accommodating movement of the cover  114  from an open position to a closed position. A protrusion  118  extends from the step-down portion  116  for receiving a corresponding bore  120  formed through a flange  122  of the cover  114  for connecting the cover to the housing  24 .  
         [0041]     Referring now to  FIG. 4 , a bottom surface  62  of the chassis  16  may include a steering trimmer  64 . Like the steering adjuster  34  of the transmitter  10 , the steering trimmer  64  may be used to ensure proper wheel alignment in the steering of the radio-controlled car  12 . For example, if the transmitter  10  is directing the radio-controlled car  12  to drive in a straight line, but the radio-controlled car  12  is veering to the right, then the steering alignment may be adjusted via the steering trimmer  64  so that the radio-controlled car  12  proceeds in a straight line as directed. Although the steering adjuster  34  and steering trimmer  64  may be used separately, it is understood that they may enable a larger adjustment to be made to the steering alignment when used together.  
         [0042]     In the present example, the steering trimmer  64  is initially in a neutral position. Rotating the steering trimmer  64  adjusts the way in which the radio-controlled car  12  responds to the signal that is received from the transmitter  10 . For example, if the transmitter  10  transmits instructions to the radio-controlled car  12  using a series of pulses (e.g., pulse modulation), then the steering trimmer  64  may be rotated to a non-neutral position (either by hand or using a tool such as the screwdriver  66 ) to alter the received pulses so that they represent a neutral state. For example, a potentiometer responsive to the rotation of the steering trimmer  64  may be used to alter a pulse width of the transmitted pulses.  
         [0043]     A plurality of slots  126 ,  128 , and  130  are formed through the bottom surface  62  of the chassis  16  for allowing access to a pair of electrical charging contacts  132  and  134  and an electrical programming contact  136 . The charging contacts  132  and  134  and the programming contact  136  of the car  12  correspond to the charging contacts  106  and  108  and the programming contact  110 , respectively, of the transmitter  10 . It is understood that the transmitter  10  and the car  12  may be connected for purposes of charging and programming by other means such as cables that connect into jacks associated with the transmitter and the car. A power switch  138  may further be provided on the bottom surface  62  of the chassis  16 . Accordingly, when the radio-controlled car  12  is placed onto the interface pad  90  of the transmitter  10 , circuits within the radio-controlled car  12  may electrically connect with corresponding circuits within the transmitter  10 . Additionally, although not shown, the car  12  may include an indicator for indicating various operating states of the car, such as the operating frequency. The indicator on the car  12  may be provided in addition to, or in place of, the indicator  30  of  FIG. 1 .  
         [0044]     Referring now to  FIGS. 5A-5F , a plurality of circuits that may be housed within the transmitter  10  are illustrated. It is understood that relationships may exist between various circuits and/or circuit components of  FIGS. 5A-5F . For example, the circuit of  FIG. 5A  includes a microcontroller unit (MCU) denoted by the reference number U 203 . The MCU U 203  includes various input and output ports, including a POWER_LED output and a CHA_LED output. The POWER_LED and CHA_LED outputs serve as inputs to the LED circuit of  FIG. 5F .  
         [0045]     Referring now to  FIG. 5A , a circuit  200  includes the MCU U 203 , a channel selection circuit  202 , a left hand/right hand selection circuit  204 , and a MCU control circuit  206 . For purposes of example, the MCU U 203  is an EM78458, made by Elan Microelectronics, with 4K of read only memory (ROM). The memory of the MCU U 203  includes a plurality of instructions for controlling various aspects of the transmitter  10 . For example, in conjunction with various circuits, the MCU U 203  may program a selected frequency of the radio-controlled car  12 , handle charging, control steering and left/right and front/back motion, and perform other tasks.  
         [0046]     The channel selection circuit  202  is associated with the channel selection switch  28  of  FIG. 1  through switches SW 203 -SW 205  and SW 207 -SW 209 , each of which corresponds to a channel  1 - 6  of the channel selection switch  28 . It is understood that any number of channels are contemplated. In the present example, only one of the switches SW 203 -SW 205  and SW 207 -SW 209  can be in a closed state (e.g., if channel  1  is selected, SW 203  may be closed, while SW 204 , SW  205 , SW 207 -SW 209  may be open). The state of the switches (e.g., open or closed) may be read by the MCU U 203  as a voltage through an analog to digital converter that is contained within the MCU U 203 . This state informs the MCU U 203  of the user-selected channel that is to be used by the transmitter  10  and the radio-controlled car  12 . After the selected channel is confirmed by comparison of the read voltage to a predefined value within the MCU U 203 , the MCU U 203  may program an integrated circuit (e.g., IC U 201  of  FIG. 5D ) through a CHCLK signal pin. This sets the transmitter  10  to transmit signals using the selected channel.  
         [0047]     The MCU U 203  may then transfer information regarding the user-defined channel to an MCU U 2  ( FIG. 6A ) within the radio-controlled car  12  via the programming contact  110 . In the present example, channel programming of the radio-controlled car  12  may be accomplished when the radio-controlled car  12  is placed onto the interface pad  90 . In some embodiments, the programming may occur in a predefined period of time, such as during the first eight seconds of a charging cycle. For example, if a user desires to change the channel from  3  to  4 , he may push the channel selection switch  28  one step upwards. This changes the input voltage at pins  6  and  7  of the MCU U 203 , and the MCU U 203  detects the selection of channel  4  by comparing the detected voltage level with an internal threshold level. The MCU U 203  then sets the transmitter  10  to transmit using the selected channel and transfers the selected channel to the radio-controlled car  12 .  
         [0048]     The left hand/right hand selection circuit  204  is associated with the left hand/right hand selection switch  36  of  FIG. 1  through a switch SW 206 . In the present example, moving the left hand/right hand selection switch  36  on the transmitter  10  from right hand to left hand (or vice versa) reverses the operation of the motion control member  40  by reversing an FB+ contact and a FB− contact ( FIG. 5B ). This enables the transmitter  10  to be adjusted for use with both right and left-handed users.  
         [0049]     With additional reference to  FIGS. 5G and 5H , one embodiment of the left hand/right hand selection switch  36  (and the corresponding switch SW 206  of  FIG. 5A ) is associated with six contact points A-F. The contact A is of positive polarity and the contact B is of negative polarity. Contact A is connected to contact F, and contact B is connected to contact E. For purposes of illustration, contact C is connected to the FB+ contact ( FIG. 5B ) and contact D is connected to the FB− contact ( FIG. 5B ).  
         [0050]     When the switch SW 206  is set for right-handed use ( FIG. 5G ), the contacts A and C are connected, and the contacts B and D are connected. This gives the contact C (and the associated contact FB+) a positive polarity, and gives the contact D (and the associated contact FB−) a negative polarity. When the switch SW 206  is set for left-handed use ( FIG. 5H ), the contacts C and E are connected, and the contacts D and F are connected. This reverses the polarity of the contacts C and D, giving the contact C (and the associated contact FB+) a negative polarity, and giving the contact D (and the associated contact FB−) a positive polarity. Accordingly, by manipulating the polarity of the FB+ and FB− contacts via the contacts A-F, the transmitter  10  may be set for right-handed or left-handed use.  
         [0051]     Referring now to  FIG. 5B , a forward/backward motion control circuit  210  housed within the transmitter  10  is associated with the motion control member  40  ( FIG. 1 ) through an input FBC. Movement of the motion control member  40  affects variable resistor VR 201 , which may be a potentiometer, as described previously. The output voltage F/B of the forward/backward motion control circuit  210  is read by the MCU U 203  ( FIG. 5A ) on pin  3 , and the MCU U 203  determines what digital signals to send to the radio-controlled car  12  based on the read voltage. As described previously, the transmitter  10  may include a motion control trimmer  74  ( FIG. 3 ) that can be used to offset undesired forward or backward motion when the radio-controlled car  12  is supposed to remain stationary. In the present example, the motion control trimmer  74  is associated with a variable resistor VR 204 .  
         [0052]     Referring now to  FIG. 5C , a left/right steering control circuit  212  housed within the transmitter  10  is associated with the steering member  32  ( FIG. 1 ) through an input LRC. Movement of the steering member  32  affects variable resistor VR 202 , which may be a potentiometer, as described previously. The output voltage L/R of the left/right steering circuit  212  is read by the MCU U 203  ( FIG. 5A ) on pin  4 , and the MCU U 203  determines what digital signals to send to the radio-controlled car  12  based on the read voltage. As described previously, the transmitter  10  may include a steering adjuster  34  ( FIG. 1 ) that can be used to offset undesired drift in the wheel alignment of the radio-controlled car  12 . In the present example, the steering adjuster  34  is associated with variable resistor VR 203 .  
         [0053]     Referring now to  FIG. 5D , a signal transmission circuit  214  housed within the transmitter  10  is used to transmit control signals from the transmitter  10  to the radio-controlled car  12 . The signal transmission circuit  214  includes a transistor Q 206 , a varactor diode D 201 , an antenna ANTI (which may be the antenna  20  of  FIG. 1 ), a crystal X 201 , and an integrated circuit (IC) U 201 , which may be an ET13X221, made by Etoms Electronics. Although not shown in  FIG. 5D , the IC U 201  includes a phase lock loop circuit, a voltage controlled oscillator, and a crystal oscillator. In the present example, the voltage controlled oscillator within the IC U 201  is operated at 27 MHz by programming a frequency counter within the IC U 201  via an input port CHCLK (pin  1  of the IC U 201 ). The IC U 201  has sixteen available channels.  
         [0054]     Data is sent from the MCU U 203  to the radio-controlled  12  via an output port DATA_OUT (pin  19 ,  FIG. 5A ) as follows. When a square-wave is generated by the MCU U 203  on the DATA_OUT port and applied through the resistor R 211 , the carrier signal is frequency shift key (FSK) modulated (e.g., it enables sub-carrier modulated signaling that can be used for data transmission, where binary ones and zeroes are represented by two different frequencies that are offset from the carrier frequency). The data is then sent to the radio-controlled car  12  via the antenna ANT 1 .  
         [0055]     Referring now specifically to  FIG. 5E , a charging circuit  216  housed within the transmitter  10  may be used in charging the radio-controlled car  12 . In the present example, the charging circuit  216  includes a power switch SW 201 , a charging switch SW 202  and associated contact pads CH+ and CH−, each of which correspond to an element of  FIG. 1 . For example, the power switch SW 201  may be connected to the power switch  26 , the charging switch SW 202  may be connected to the charging button  112 , and the contact pads CH+ and CH− may correspond to the electrical charging contacts  106 ,  108 , respectively.  
         [0056]     In operation, the power switch  26  of the transmitter  10  is turned to “on,” which actuates the power switch SW 201  of the charging circuit  216 , providing an electrical connection to a battery BATT. (In the present example, the power switch  138  of the radio-controlled car  12  is also turned to “on” prior to placement of the radio-controlled car  12  on the transmitter  10 .) When the radio-controlled car  12  is placed onto the interface pad  90  of the transmitter  10 , the charging button  112  is depressed, actuating the charging switch SW 202 . When the charging switch SW 202  is actuated, the MCU U 203  ( FIG. 5A ) alters the state of pin  13  and turns on transistor Q 203  (which then turns on transistors Q 202 , Q 207 , and Q 208 ). This provides power from the battery BATT to the contact pads CH+ and CH−. A timer is started within the MCU U 203  to limit the amount of time that the battery of the radio-controlled car  12  is allowed to charge, thereby preventing an overcharge from occurring and damaging the battery. In the present example, the charging duration is approximately one minute and the charging rate is approximately 10 C (where C is the one hour discharge current). An IC U 202  provides a regulated voltage output to the MCU control circuit  206  ( FIG. 5A ) and the signal transmission circuit  214  ( FIG. 5D ).  
         [0057]     Referring now to  FIG. 5F , a light emitting diode (LED) circuit  218  housed within the transmitter  10  powers the indicator  30  to indicate an operating state of the transmitter  10 . In the present example, the indicator  30  comprises one or more LEDs that are used to represent a variety of states using one of three colors that may be blinking or steady. For example, green and steady may indicate that the transmitter  10  is powered on or in trickle charge mode; red and blinking may indicate that channel programming (of the radio-controlled car  12 ) is in progress; red and steady may indicate that the radio-controlled car  12  is being charged; and amber and steady may indicate that channel programming has failed. It is understood that these states are exemplary, and that other states and/or combinations may be used. These states are controlled by the MCU U 203  ( FIG. 5A ) via a POWER_LED output (pin  14 ) and a CHA_LED output (pin  11 ).  
         [0058]     Referring now to  FIGS. 6A-6D , a plurality of circuits that may be housed within the radio-controlled car  12  are illustrated. It is understood that relationships may exist between various circuits and/or circuit components of  FIGS. 6A-6D . For example, the circuit of  FIG. 6A  includes a MCU denoted by the reference number U 2 . The MCU U 2  includes various input and output ports, including a W 2 R output and a W 2 L output. The W 2 R and W 2 L outputs serve as inputs to the motor control circuit of  FIG. 6B .  
         [0059]     Referring now to  FIG. 6A , a circuit  220  includes the MCU U 2 , an IC U 1 , a low noise amplifier circuit  222 , a receiver circuit  224 , and a MCU control circuit  226 . For purposes of example, the MCU U 2  may be an EM78458, made by Elan Microelectronics, and the IC U 1  may be an ET13X210, made by Etoms Electronics. The MCU U 2  may include a plurality of instructions for controlling various aspects of the radio-controlled car  12 . For example, in conjunction with various circuits, the MCU U 2  may control steering and forward/backward motion.  
         [0060]     The channel information transferred from the MCU U 203  ( FIG. 5A ) is received by the MCU U 2 . The user selected channel may be stored in memory associated with the MCU U 2 , which may then set the radio-controlled car  12  to receive signals using the selected channel by setting the IC U 1  via pins D 0 -D 3 . In the present example, as the channel data is stored in volatile memory, it will be lost when power is lost or reset occurs, but will be reprogrammed again when the battery is charged.  
         [0061]     The FSK modulated signal transmitted by the transmitter  10  via the antenna  20  is received by an antenna ANT 2  (which may be the antenna  18  of  FIG. 1 ) associated with the low noise amplifier circuit  222 . The received signal is amplified by the low noise amplifier circuit  222  and passed to the IC U 1 , which mixes the signal down to an intermediate frequency. The intermediate frequency signal is then demodulated and waveform shaped to recover the original control data stream. The data stream is then decoded by the MCU U 2  and used to control a first motor control circuit  228  ( FIG. 6B ) and a second motor control circuit  230  ( FIG. 6C ), which control steering of the front wheels and forward/backward motion, respectively.  
         [0062]     More specifically, the MCU U 2  controls the front wheels via two output ports W 2 R (pin  8 ) and W 2 L (pin  9 ), which correspond to circuit inputs of the same name in  FIG. 6B . The steering trimmer  64  may be associated with the circuit of  FIG. 6B  to enable a user to manipulate the circuit in order to align the front wheels of the radio-controlled car  12 . For example, the steering trimmer  64  may be associated with a variable resistor (not shown) as described previously with respect to the circuit elements VR 204  and VR 203  of  FIGS. 5B and 5C , respectively. Similarly, the MCU U 2  controls forward/backward motion via two output ports WIF (pin  6 ) and WIB (pin  7 ), which correspond to circuit inputs of the same name in  FIG. 6C . Although not shown in the present example, a user-adjustable component may be associated with the circuit of  FIG. 6C  to enable a user to manipulate the circuit in order to adjust the forward/backward motion of the radio-controlled car  12 . For example, such component may be associated with a variable resistor (not shown) as described previously.  
         [0063]     Referring now to  FIG. 6D , a DC-DC converter circuit  232  includes a switch SWI, contact pads CH+ and CH−, and a DC-DC converter U 3 . The switch SW 1  corresponds to the power switch  138 , and the contact pads CH+ and CH− may correspond to the electrical charging contacts  132 ,  134  ( FIG. 4 ), respectively. When the switch SWI is closed, power is provided to the circuit  232 . The DC-DC converter U 3  steps the battery voltage up from 2.4V to 3V.  
         [0064]     To operate the radio-controlled car  12 , a user turns both the power switch  26  of the transmitter  10  and the power switch  138  of the radio-controlled car  12  to “on.” The indicator  30  may emit a green color to indicate that the transmitter  10  is on. If the battery of the radio-controlled car  12  is to be charged or the car is to be programmed with a different frequency, the radio-controlled car  12  is placed on the interface pad  90  of the transmitter  10  to engage the catches  92  and  94 . By placing the radio-controlled car  12  on the interface pad  90 , the charging button  112  of the transmitter  10  is activated, which begins the charging process of the radio-controlled car  12  via the electrical connection between the charging contacts  132  and  134  of the radio-controlled car  12  and the charging contacts  106  and  108  of the transmitter  10 .  
         [0065]     During charging, the operating frequency of the radio-controlled car  12  and the transmitter  10  may be modified by moving the channel selection switch  28  to a desired operating channel. The indicator  30  may emit a blinking red color to indicate channel frequency programming. Upon frequency selection, the indicator  30  may emit a steady red color to indicate charging. When the charging process is completed, the indicator  30  may emit a green color.  
         [0066]     If channel programming fails, the indicator  30  may emit an amber color to indicate such failure. The user may then remove the radio-controlled car  12  from the transmitter  10  to clear the programming failure, and then reposition the radio-controlled car  12  on the transmitter  10  to restart the charging and programming operations.  
         [0067]     When the selected operating frequency is programmed and the radio-controlled car  12  has been charged, the radio-controlled car  12  may be removed from the transmitter  10  by pressing the release button  38 . Prior to controlling the radio-controlled car  12 , the user may configure the transmitter  10  for right or left-handed use. For example, a right-handed user may move the left hand/right hand selection switch  36  to the “right” position, which configures the motion control member  40  to impart forward motion to the radio-controlled car  12  when the motion control member is moved in a left direction and to impart backward motion to the car when the motion control member is moved in a right direction. Generally, a right-handed user may control the steering member  32  using the left hand while manipulating the motion control member  40  with the right hand. If the alternative configuration is desired, the user may move the left hand/right hand selection switch  36  to the “left” position.  
         [0068]     The radio-controlled car  12  may then be controlled by gripping the transmitter  10  and moving the steering member  32  and the motion control member  40 . If the wheel alignment of the radio-controlled car  12  drifts during neutral steering, then the steering trimmer  64  and/or the steering adjuster  34  may be adjusted. Additionally, if the radio-controlled car  12  moves when the motion control member  40  is in a neutral position, the motion control trimmer  74  may be adjusted accordingly.  
         [0069]     The present invention has been described relative to a preferred embodiment. Improvements or modifications that become apparent to persons of ordinary skill in the art after reading this disclosure are deemed within the spirit and scope of the application. For example, a variety of alternate circuit configurations and components may be used to achieve the functionality of the circuits described above. Furthermore, alternate controls may be provided that accomplish similar functions to those described herein. Still further, functionality such as adjustments to the steering and/or to the forward/backward motion may be automatically achieved via one of the microcontrollers housed within the transmitter  10  or the car  12 . Accordingly, it is understood that several modifications, changes and substitutions are intended in the foregoing disclosure and, in some instances, some features of the invention will be employed without a corresponding use of other features. It is also understood that all spatial references, such as “right”, “left,” “longitudinal,” “radial,” top, side,” “back,” and “front” are for illustrative purposes only and can be varied within the scope of the disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Technology Category: 1