Slot car racing has been a popular hobby for many decades. Part of the appeal is in producing sophisticated race tracks and then racing others on the track. The applicant has designed a new slot car racing system with the aim of updating and improving the existing systems that are available. A detailed description of the new slot car racing system will be given below in the specific description of the embodiments. This new system incorporates many different inventions, some of which are specific to slot car racing systems and others of which have more general applicability to toy systems in general.

According to one aspect, the present invention provides a slot car racing system for racing one or more slot cars around a slot car track having at least two slots. The slot car racing system includes a user device for receiving user input and for generating user control signals for controlling the at least one slot car. The system also includes a main controller

for receiving the user control signals and for generating control signals for driving the slot car along a slot. In a preferred embodiment, the main controller can transmit a change lane request to the slot car which, after receiving the change lane request communicates the request to a change lane controller provided in the track which controls a change lane track segment, to cause the slot car to change slot.

In a preferred embodiment, the main controller transmits digital messages to the slot car via the slot on the track, as this facilitates the communication between the main controller and the slot car. Further, the slot car preferably communicates the change lane request to the track by transmitting an electromagnetic signal to the track which allows for quick and reliable change lanes to occur.

Although the slot car can communicate with the track via an appropriate mechanical link, this is not preferred, because such mechanical links usually require springs and other mechanical components which have a limited lifespan and tend to be less reliable. Additionally, mechanical links tend to be slower and can result in two slot cars changing lane when it was

only desired for one of the slot cars to change.

In a preferred embodiment, the slot car also transmits an ID signal to the track, which the main controller can use to keep track of each slot car on the slot car track.

Exemplary embodiments of the invention will now be described with reference to the following drawings in which: Figure 1 is a schematic overview of the new slot car racing system described herein; Figure 2a is a view from the front of a main unit and a base unit forming part of the slot car racing system shown in Figure 1; Figure 2b is a side view of the main unit and the base unit shown in Figure 2a, illustrating the way in which the main unit is removably connectable to the base unit; Figure 3a is a schematic block diagram illustrating the main components of the main unit shown in Figure

2; Figure 3b is a block diagram illustrating the software modules forming part of the main unit shown in Figure 3a ; Figure 4a is a circuit diagram illustrating the main components of a hand controller forming part of the system shown in Figure 1 and the way in which it is connected to the main unit shown in Figure 3a; Figure 4b is a plot illustrating the way in which the signal from a hand controller varies with throttle position and with the status of two buttons on the hand controller; Figure 5 is a plot illustrating the way in which a hand controller control module determines a desired speed value for a determined hand controller throttle position; Figure 6a illustrates the form of a data packet that is transmitted to a slot car for controlling the operation of the slot car on the track;

Figure 6b is a timing diagram illustrating the form of a pulse width modulation signal generated in dependence upon the speed value determined for a current hand controller throttle position; Figure 7 is a block diagram illustrating the main components of a drive circuit used to apply current to a slot of the slot car racing system shown in Figure 1; Figure 8a is a schematic block diagram illustrating the operation of a telemetry control module shown in Figure 3b in recording race telemetry data for a current slot car race in progress; Figure 8b illustrates the operation of the telemetry control unit shown in Figure 3b in the generation of driving signals for driving a slot car from stored telemetry data; Figure 9 is a block diagram illustrating the main components of an in-car module forming part of the slot car shown in Figure 1 ; Figure 10 schematically illustrates the form of a lane

change track segment which allows slot cars to change slot on the track ; Figure lla schematically illustrates the form of a solenoid controlled gate used to control the changing of lanes in a first non-lane change position; Figure lib schematically illustrates the solenoid controlled gate shown in Figure lia in a second lane change position; Figure 12a schematically illustrates the main components of a lane change control module used to control the lane change track segment shown in Figure 10; Figure 12b is a timing diagram illustrating the possible change lane control signals that the lane change control module shown in Figure 12a may receive from passing slot cars; Figure 13 is a schematic block diagram illustrating the main functional components of a personal computer forming part of the system shown in Figure 1;

Figure 14 is a block diagram illustrating the main components of an interface and pre-processor unit forming part of the personal computer shown in Figure 13; Figure 15 is a block diagram illustrating the main functional components of application logic forming part of the personal computer shown in Figure 13; Figure 16 is a block diagram illustrating the main functional components of a user interface shown in Figure 13; Figure 17 schematically illustrates the form of a slot car forming part of the system shown in Figure 1 and illustrating the connection of a retractable in-car module; Figure 18 schematically illustrates the electrical connections provided in a dummy in-car module which allows the slot car shown in Figure 17 to operate with a conventional track; Figure 19a is a cross-sectional view of a preferred solenoid lane change device used to control the

changing of lanes by the slot cars; Figure 19b is a plan view of the solenoid controlled lane change device shown in Figure 19a ; Figure 20 schematically illustrates a preferred slot car detection track module which is provided separately from a slot car change lane track module.

Overview Figure 1 is a schematic diagram illustrating a new digital slot car racing system. The system includes a main unit 1 which can control the driving of up to six motorised slot cars 3-1 to 3-6 on two slots 11-1 and 11-2 of a slot car track 5, in dependence upon user control signals input via hand held controllers 7-1 to 7-6 respectively. In particular, the user controls the position of a throttle 9-1 to 9-6 on the hand controller 7 which is detected by the main unit 1 and used to define a digital speed message which is transmitted to the corresponding slot car 3 on the track 5, to thereby control the speed of that slot car 3 racing around the track 5. Figure 1 also illustrates that the main unit 1 receives power from an AC power converter 13.

In this embodiment, the main unit 1 is also arranged to receive change lane requests from the users via the hand controllers 7. In response, the main unit transmits a digital change lane request to the corresponding slot car 3 on the track 5. After receiving a change lane request, the slot car 3 transmits a signal to a trackside unit (not shown) which controls a change lane gate (not shown) on the track 5 so that the slot car 3 can change to the other slot 11. The way in which this is achieved will be described in more detail later.

In this embodiment, the main unit 1 is arranged to record various telemetry data for one or more of the slot cars 3 as they race around the track 5, so that the main unit 1 can replay part or all of a race by using the stored telemetry data to drive the corresponding slot car (s) 3 around the track 5 without input from the user. The way in which this is achieved will be described in more detail later.

In this embodiment, the main unit 1 can also be connected to a personal computer 15 via which the user can set various race options for the main unit 1 which

are then downloaded to the main unit 1 to control the race. Additionally, the telemetry data recorded by the main unit 1 can be passed to the PC 15 either for analysis purposes after the race by the users, or for generating a virtual (graphical) simulation of the race on the display of the PC 15.

As shown in Figure 1, the PC 15 can also connect to other user's main units 17 via the Internet 19. In this way, the telemetry data recorded by the main unit 1 can be transmitted over the Internet 19 to a remote main unit 17, which can then use this telemetry data to automatically drive a remote slot car 20 around the remote track 21. The telemetry data generated by the main unit 1 may be transmitted at the end of a race as a single data file or it may be streamed as a continuous data stream to the remote unit 17 and used to generate an appropriate real time simulation or to drive the remote slot car 20 around the remote track 21 in real time. Similarly, telemetry data recorded by the remote main unit 17 from one or more of the slot cars 20 being driven around the remote track 21 can also be transmitted over the Internet 19 and received by the PC 15. The PC 15 can then either use the received telemetry data to display a virtual

simulation of the remote slot cars 20 racing around the remote track 21 or pass the data to the main unit 1 to actively drive one or more of the slot cars 3 around the track 5.

Additionally, in this embodiment, the users can control a virtual race on the PC 15 using the hand controllers 7 to control the speed of virtual slot cars in the virtual race. In this virtual race, the main unit 1 does not use the hand controller signals to transmit messages to the track 5. Instead, it simply streams the hand controller signals directly to the PC 15 which uses the signals to update the position of the corresponding cars in the virtual race. Indeed, in this operating mode, the main unit 1 does not need to be connected to the track 5.

A brief description has been given above of the operation of the new slot car racing system of this embodiment. A more detailed description will now be given of the main components of the system together with a more detailed description of the above described functionality.

Main Uni Unit A front view of the main unit 1 is shown in Figure 2a.

As shown, the main unit includes an LCD display 51 for displaying settings and other information to the user and five buttons-a back button 53-1; a forward button 53-2; a play/edit button 53-3; a start button 53-4 and a set/stop button 53-5. As will be described in more detail below, these buttons are provided to allow the user to control the mode of operation of the main unit 1.

In this embodiment, the main unit 1 is coupled to the track 5 via a base unit. Figure 2b is a side view showing the way in which the main unit 1 connects to the base unit 65 which is directly connected to the track 5. As shown, the main unit 1 and the base unit 65 are arranged so that the main unit 1 can be easily lifted off the base unit 65 and transported to, for example, another room where the personal computer 15 is located. An appropriate electrical connector (not shown) is provided on the main unit 1 and the base unit 65 for providing the appropriate electrical connections from the main unit 1 through to the track 5 via the base unit 65.

Figure 3a is a functional block diagram illustrating the principal components of the main unit 1 used in this embodiment. As shown, the main unit 1 includes a microprocessor 101 whose operation is controlled by software stored in non-volatile memory 103. The main unit 1 also includes six hand controller interfaces 105-1 to 105-6 to which the respective hand controllers 7-1 to 7-6 can connect. The main unit 1 also includes a slot drive circuit 107 which is controlled by the microprocessor 101 to apply the appropriate voltage across the slots 11-1 and 11-2 of the track 5 (i) to power the slot cars 3; and (ii) to carry digital messages to the slot cars 3 to control their operation. As shown, the drive circuit 107 outputs the drive signals to a base unit interface 109 which connects the main unit 1 to the base unit 65 shown in Figure 2b. The slot drive circuit 107 also monitors the electrical current applied to the track 5 and passes this electrical current data back to the microprocessor 101 for use in detecting track overload (short circuit) conditions.

In this embodiment, a lap detector (not shown) is provided on each slot at the start/finish line in order to detect when each slot car 3 passes the

start/finish line. Each lap detector includes a light source and a light detector positioned on either side of the slot 11 so that as the slot car 3 passes by the start line, the guide blade on the slot car 3 (which is received in the slot 11) breaks the light beam. As illustrated in Figure 3a, in this embodiment, the lap detectors are connected directly to the microprocessor 101 via the base unit interface 109. The microprocessor 101 can therefore determine the time at which a slot car 3 passes the start/finish line.

However, since several slot cars 3 can travel on the same slot 11 and since the slot cars 3 can change slot 11, the lap detectors do not provide sufficient information to establish which slot car 3 has passed the start/finish line. In this embodiment, therefore, each of the slot cars 3 is arranged to transmit an optical ID signal to an ID detector (photodetector) provided in each slot 11 in the vicinity of the start/finish line (in this case shortly before the start/finish line), so that the identity of the slot car 3 passing the start/finish line can be determined.

As shown, in this embodiment, the signals from these ID detectors are passed via the base unit interface 109 to a slot car ID co-processor 108, which processes

the signals to identify which of the slot cars 3 is about to pass through the lap detector. This information is then passed directly to the microprocessor 101 which uses the information together with the signals from the lap detectors to control a lap counter for each of the slot cars 3. In this embodiment, the power for driving the lap detectors and the ID detectors is provided by the slot drive circuit 107.

Figure 3a also shows the user input buttons 53 and the LCD display 51. The microprocessor 101 is connected to the display 51 via a databus 111 and a display driver 113. The microprocessor 101 also uses the data bus 111 to access the memory 103, a PC interface 115 and an accessory unit interface 117. The PC interface 115 (such as a USB interface) provides the interface for connecting the main unit 1 to the personal computer 15. The accessory unit interface 117 allows an accessory module (not shown) to be connected to the main unit 1. For example, an accessory module may be provided for controlling a gantry of lights provided at the start/finish line on the track 5 which can be controlled by the microprocessor 101 in accordance with a current racing mode that has been set or in

accordance with a current race in progress.

Finally, as shown in Figure 3a, the main unit 1 includes a loudspeaker 121 which is controlled by the microprocessor 101 via a loudspeaker driver 123. This allows the microprocessor 101 to be able to output sounds to the user before, during and after a race.

For example, the microprocessor 101 may output a beep sound via the loudspeaker 121 in order to signify to the users the start and/or the end of the race.

As discussed above, the microprocessor 101 operates to control the operation of the main unit in accordance with software initially stored in the memory 103 and downloaded and run in the microprocessor 101. Figure 3b is a block diagram illustrating the main software modules used, in this embodiment, to control the microprocessor 101. As shown, the software modules include: 1) a user interface control module 131 which controls the interaction with the user via the display 51, the user buttons 53 and the loudspeaker 121; 2) a telemetry control module 133 which operates to

control the recording of the telemetry data and the subsequent use of the stored telemetry data to control the automatic driving of a slot car around the track 5; 3) a function control module 135 which controls the functional mode of operation of the main unit 1 for different race scenarios; 4) a current overload detection module 137 which is operable to monitor the current applied to each slot 11 and to detect a current overload caused by, for example, the short circuiting of one of the slots 11 and in response to inhibit the output of current to the track 5; 5) a slot car communications control module 139 which is operable to generate the appropriate control messages that are output to the slot drive circuit 107; 6) hand controller (H/C) control modules 141 which operate to receive the signals from the hand controller interfaces 105 and from them to determine the present hand controller throttle 9 positions and hence the appropriate control messages to be passed to the corresponding slot cars 3; 7) a data bus communications control module 143

which is used to control communications between the microprocessor 101 and the memory 103, the accessory unit and the personal computer 15; and 8) a lap detector control module 145 which receives the signals from the lap detectors and the slot car ID data from the slot car ID co-processor 108 and which generates a lap control signal (LAP) for each slot car which indicates when the slot car passes the start/finish line.

In this embodiment, the main unit has two modes of operation: stand-alone and PC-connected. The stand- alone mode is when the main unit 1 is not connected to the personal computer 15 during racing and in this mode internet racing is not supported (unless an appropriate communications accessory is provided and connected to the accessory interface 117). In PC- connected mode, full internet and virtual simulation modes are supported and the PC 15 can control the operating mode of the main unit 1.

Stand-Alone Mode The main unit 1 enters the stand-alone mode when it is not connected to the personal computer 15. If the main unit 1 has not been programmed by the personal

computer 15 or the user, then factory settings are used. When the main unit 1 is connected to the base unit 65, it enters a pre-race state and an appropriate race screen is displayed to the user on the display 51. In this pre-race state, the user can either access a setup screen by pressing the edit button 53-3 or they can start a race by pressing the start button 53-4. Pressing the edit button 53-3 once on the pre- race screen enters the edit mode. The left and right keys 53-1 and 53-2 can then be used to select a race attribute or a slot car attribute that is to be changed. Pressing edit for a second time, allows the particular attribute to be changed, again using the left and right keys 53-1 and 53-2 to select the available values. The values can then be saved by pressing the set/stop key 53-5.

When the user presses the start button 53-5 in the pre-race state, the main unit 1 will enter a race state in which the main unit 1 will count down the start of the race and output an appropriate signal (e. g. via the loudspeaker 121) to indicate the start of the race to the user (s). During the race, the display 51 will display the current racing mode and other relevant race data and the main unit 1 will

operate in accordance with the currently programmed racing mode.

At the end of the race, the main unit 1 will enter a finish state in which it will output a signal to the users (e. g. via the loudspeaker 121) indicating the end of the race. The main unit 1 will also display the positions and names of the users to identify the winner. The main unit 1 remains in this state until the user presses the set/stop button 53-5 at which point the main unit returns to the pre-race mode.

Additionally, at any time during a race, the race can be stopped by pressing the set/stop button 53-5 and the whole main unit 1 can be reset to the factory settings by pressing the left and right buttons 53-1 and 53-2 and the start button 53-4 together.

PC-Connected Mode The main unit 1 enters this mode as soon as it is connected to the personal computer 15. In this mode, the display 51 indicates that it is connected and communicating with the personal computer 15. In this embodiment, when in the PC-connected mode, the operation of the main unit 1 is controlled by the PC

15. Additionally, in this mode, the user can start and stop a race either by pressing an appropriate key on their PC 15 or the appropriate button 53 on the main unit 1. During a race, the main unit 1 will stream the appropriate hand controller data (telemetry data) to the PC 15. At the end of the race, the main unit 1 will again output a signal to the user indicating the end of the race and the positions of the users in the race will be output to and displayed by the PC 15. The user can then return the PC 15 and the main unit 1 to the pre-race state by pressing an appropriate key on the PC 15.

Again, in this PC-connected mode, the race can be stopped at any time by pressing the set/stop button 53-5 which will be signalled to the personal computer 15. Similarly, the system can be reset by pressing the left and right buttons 53-1 and 53-2 together with the start button 53-4.

Racing Modes As discussed above, in this embodiment, the main unit 1 can be programmed into one of a number of different racing modes. A brief description of these different racing modes is given below:

1) Grand Prix-in which a plurality of users race slot cars 3 around the track 5 until they complete a fixed number of laps. In this mode, the LCD 51 displays the number of laps left in the race and as each user passes the start line, the position of the user in the race. The user can define the number of laps to be completed using the buttons 53 or, if connected, via the PC 15.

2) Endurance-in which users race slot cars 3 around the track 5 for a fixed user-defined period of time. The winner is the user who completes most laps or the same number of laps in the fastest time. In this mode, the display 51 displays the time left in the race and flashes the number of laps completed by each user when they pass the start line.

3) Rally-in which users take turns to race a slot car 3 to complete a user-defined fixed number of laps. The winner is the user who completes the fixed number of laps in the fastest time. In this mode, the display 51 displays the number of laps left together with the time since the user started the race. In this mode circuits can be

defined which require a certain number of slot changeovers (lane changes), so that for example, one circuit corresponds to two or more laps.

4) Pursuit-in which the slot cars 3 start together and race on the track 5 until one car catches up and laps the other. In this mode, the display 51 displays the name of the user catching up and the time gap between the race leader and the or each other user.

5) Arcade-in this mode, users complete a user- defined fixed number of laps within a given "check-point"time period. The users then carry on to complete the same number of laps in a reduced time period. The race continues in this manner until the last user fails to make the required number of laps in the checkpoint period.

This arcade mode is a continuous race and not a series of races. Hence, if a user completes a stage with e. g. two seconds spare, then they have two seconds extra time available for the next stage. In this mode, the display 51 displays the time left and the number of laps left to reach the next checkpoint.

6) Advanced Qualify-in which users record their fastest time to complete a lap. In this mode,

the display 51 will display the current user's best lap time and the last lap time.

7) Virtual Race-in which the hand controller signals are not used to control messages sent to the track 5 but instead are passed to the PC 15 for controlling a virtual race on the local PC 15 and/or on a remote terminal connected to the internet 19 or some other data network.

As discussed above, the current racing mode and its attributes can be defined by the user either via the PC 15 or using the buttons 53 on the main unit 1.

Hand Controller Figure 4a is a circuit diagram illustrating the main components of each of the hand controllers 7 shown in Figure 1 and showing the corresponding hand controller interface 105 in the main unit 1. As shown, the hand controller interface 105 includes a resistor (RI) 149 which is connected at one end to a supply voltage at 5 volts and at the other end to a terminal 151 which is connected into an analogue to digital converter (not shown) in the microprocessor 101 and to a first terminal 153 of the hand controller 7. As shown, the first terminal 153 in the hand controller 7 is

connected to a variable resistor (R) 155 whose value is controlled by the user controlled throttle 9. The other end of the variable resistor 155 is connected in series with two further resistors (R3) 157 and (R4) 159, with the other end of resistor R4 159 being connected to a second terminal 161 of the hand controller 7. As shown, the second terminal 161 of the hand controller 7 is connected, in use, to ground in the hand controller interface 105. The hand controller 7 is therefore connected to the main unit 1 by only two wires and the set of resistors Ri to R4 are connected in a potentiometer arrangement so that the voltage VRc appearing between terminals 151 and ground within the hand controller interface 105 varies with the value of the variable resistor 155, which in turn varies with the position of the user controlled throttle 9.

Additionally, as shown in Figure 4a, the hand controller 7 also includes two user controlled switches 163 and 165 which, when pressed by the user, add resistors R3 and R4 respectively to the potentiometer. This change of resistance of the circuitry in the hand controller 7 results in a step change in the voltage VH/c input to the microprocessor

101.

Figure 4b is a plot illustrating the way in which the voltage VH/C input to the microprocessor 101 varies with varying throttle position between a minimum throttle position (0min) and a maximum throttle position (#max), when the buttons 163 and 165 are and are not pressed.

As shown, in this embodiment, the hand controller 7 is designed to output four distinct voltage ranges, depending on the position of the throttle (defined by the value of the variable resistor R2) and the status of switches 163 and 165. In this embodiment, switches 163 and 165 are normally closed unless the switch is actuated by the user. Therefore, in this embodiment, when neither switch 163 and 165 is actuated, the input voltage (VH/C) will vary with throttle position in accordance with the characteristic labelled M1 defined by: If the user actuates switch 163, then resistor R3 will be switched in series with resistor R2 and the input voltage (V./,) will vary with the throttle position (H) in accordance with the plot labelled M2 defined by:

If the user actuates switch 165 and not 163, then resistor R4 will be switched in series with resistor R2 and the input voltage (VH/C) will vary with the throttle position (Q) in accordance with the plot labelled M3 defined by: If the user actuates both switches 163 and 165, then resistors R3 and R4 will be switched in series with resistor R2 and the input voltage (VH/C) will vary with the throttle position (0) in accordance with the plot labelled M4 defined by: In this embodiment, the value of resistor R1 is 18K# ; resistor R2 can vary between 0 and 5KQ ; the value of

resistor R3 is 8*2ka ; and the value of resistor R4 is 18K#. These values of resistances have been chosen to ensure that there is a unique input voltage VH/C for any combination of throttle position and switch positions.

H/C Control Module In this embodiment, each H/C control module 141 receives the input voltage VH/C from the corresponding hand controller 7. In particular, it receives a digitised value (representing the present value of the voltage VH/C) generated by the analogue to digital converter which outputs a new digitised value every 2.33 milliseconds. The H/C control module 141 then uses the. current input voltage value VH/c to determine the present position (0) of the corresponding throttle 9 and to determine the current status of the control buttons 163 and 165. The H/C control module 141 then converts the determined position of the throttle 9 into an appropriate speed value through a pre-stored and user definable function (f (0))-In this embodiment, a linear function is used and is shown in Figure 5. As shown, the present position (t/c (i) ) of the throttle 9 is linearly mapped through the function (f (0)) to the appropriate speed value (i. e. SPD (i)).

In this embodiment, the microprocessor 101 uses the determined status of the control buttons 163 and 165, to control additional functionality of the race. In particular, if the H/C control module 141 detects that the button 163 is being pressed, then the microprocessor 101 uses this detection to control a "change lane"function during the race. Similarly, if the H/C control module 141 detects that the push- button 165 is being pressed, then the microprocessor 101 uses this to control the breaking of the slot car 3 on the track 5. Finally, if the H/C control module 141 detects that both push-buttons 163 and 165 are being pressed, then the microprocessor 101 uses this to control a"pit stop"function.

Therefore, in this embodiment, each of the H/C control modules 141 outputs a present speed value (SPD), a change lane control signal (LANE), a brake control signal (BRK) and a pit stop control signal (PIT).

In a conventional slot car racing system, the determined position of the throttle 9 is used to control the amplitude of a DC current that is applied to the corresponding slot 11 of the track 5. In this

embodiment, since more than one slot car 3 can be driven on the same slot 11, the main unit 1 is arranged to transmit digital messages to each of the slot cars 3 via the slots 11, which messages define the speed at which they should move along the track 5. The slot cars 3 must therefore receive and decipher the messages from the slot 11 to determine the speed at which it should drive its internal motor. The power for each of the slot cars 3 is also provided by the signal applied to the slots 11. Therefore, in this embodiment, the main unit is arranged to apply a bi-polar pulse width modulated (PWM) voltage across each of the slots 11. The bi-polar nature of. the voltage allows the slot cars 3 to always be able to extract power from it and the modulation of the pulse width allows the main unit to send the messages to the slot cars 3.

When racing slot cars 3 on the track 5, the speed value, lane change control signal (LANE) and the brake control signal (BRK) determined by the H/C control module 141 are output to the slot car communications control module 139 shown in Figure 3b. This data and the pit stop control signal (PIT) is also output to the function control module 135, which controls the

race functionality, such as the monitoring of pit stops that the user must make during the race. In this embodiment, the speed value, the lane change control signal, the brake control signal and the pit stop control signal are also output to the telemetry control module 133 which stores the data together with a time stamp in the memory 103 as the telemetry data for the race. However, when the signals from the hand controllers 7 are being used to control a virtual race on the PC 15, the speed value, the lane change control signal, the brake control signal and the pit stop control signals generated by the H/C control module 141 are not passed to the slot car communications control module 139 but instead are streamed to the PC 15 to control the virtual race.

Slot Car Communications Control Module As discussed above, users can directly control the speed at which the slot cars 3 race around the track 5 using the hand controllers 7. Alternatively, telemetry data generated during a race can be recorded and then played back to control the automatic driving of the slot cars 3 around the track 5. Similarly, telemetry data can be received from a remote location via the associated PC 15. Therefore, in this

embodiment, the slot car communications control module 139 can receive speed values, lane change control signals and brake control signals either from the H/C control modules 141 or from the telemetry control module 133 or from the data bus communications control module 143. The source from which the slot car communications control module 139 will use this data is programmed in advance in dependence upon the race mode settings defined by the function control module 135, which in turn are set by the user via the PC 15 or the user input buttons 53.

Regardless of the source of the speed, lane change and brake control signals, the function of the slot car communications control module 139 is to use these signals to generate appropriate messages to be sent to the slot cars 3 and to use these messages to modulate a pulse width modulated (PWM) control signal for output to the slot drive circuit 107. Figure 6a schematically illustrates the form of a data packet 200 generated in this embodiment by the slot car communications control module 139. As shown, the data packet 200 includes a header portion 201, a message portion 202 and a check-sum portion 204.

In this embodiment, the header portion comprises one byte of data which indicates the message type. In this embodiment, there are three different message types-an idle message, a set car ID message and a drive car message.

In the embodiment, the message portion 202 comprises six bytes of data, one byte per slot car 3 (byte i for slot car 3-1, byte 2 for slot car 3-2... byte 6 for slot car 3-6). In an idle message, this message portion 202 is ignored. In a set car ID message, each of the six bytes is set to the value of the new car ID (a value in the range 1 to 6). The way in which the slot cars 3 are programmed with their ID will be described in more detail later. For a drive car message, the lower six bits of each byte indicate a speed in the range 0 to 63 for the corresponding slot car 3, the sixth bit indicates a request to change lane and the seventh bit indicates a request to brake.

In this embodiment, the check-sum portion 204 also comprises one byte and is obtained by XORing the other seven bytes in the packet and then XORing the result with the binary equivalent of 255. As is conventional, the check-sum portion 204 is used by the

slot cars 3 to verify the data packet 200 that is recovered from the slot signal.

As discussed above, the message to be transmitted to the slot cars 3 is used to modulate the pulse width of a PWM signal. Figure 6b illustrates the form of the PWM control signal generated by the slot car communications control module 139. In this embodiment, the frequency of the PWM signal is fixed at 20 kHz and one bit of the data packet 200 is carried in each period. As shown in Figure 6b, in this embodiment, the slot car communications control module 139 transmits a binary zero by setting the time period of the low and high of the PWM signal to 116ps and transmits a binary one by setting the low and high time period of the PWM signal to 58ys.

In this embodiment, the slot car communications control module 139 can also receive control instructions from the function control module 135 which override the control signals generated from the user's hand controller 7. This can be used, for example, to ensure that each of the users take the required number of pit stops during a race. As

discussed above, the user identifies to the main unit 1 when a pit stop is being taken by stopping the slot car 3 and pressing both push buttons 163 and 165. If the function control module 135 detects that the user has not taken the appropriate pit stops, then it can penalise the user by slowing the user's slot car 3 by overriding the speed value input to the slot car communications control module 139 from the H/C control module 141. In these circumstances, the slot car communications control module 139 will generate the message portion 202 in accordance with the speed value generated by the function control module 135.

In this embodiment, the function control module 135 also controls the slot car communications control module 139 to allow the users to perform a"brake start"at the beginning of the race. In this brake start mode, the function control module 135 outputs a zero speed control signal to the slot car communications control module 139 to override the speed control value generated by the H/C control module 141, provided the user is still pressing the brake button 165 and the race has not yet started.

After the race has started, the function control module 135 stops overriding the hand controller speed

value as soon as the user releases the brake button 165. In this embodiment, if the function control module 135 detects that the user releases the brake button 165 before the beginning of the race, it also briefly stops overriding the hand controller speed signals to allow the slot car to start. However, since this will be a false start, the function control module 135 penalises the user for a period of time by again overriding the speed control signals from the H/C control module 141. The duration of this false start penalty is a race attribute which can be defined by the user via the user input buttons 53 or the PC 15.

Slot Drive Circuit Figure 7 is a block diagram illustrating the main components of the slot drive circuit used in this embodiment to generate the drive current that is applied to the slots 11. As shown, the pulse width modulated control signal (PWM) generated by the slot car communications control module 139 is input to a bi-polar bridge circuit 205 which amplifies and converts the uni-polar PWM control signal generated by the microprocessor into a corresponding bi-polar PWM voltage with no DC offset and with a peak-to-peak

voltage swing of 12 volts. This bi-polar PWM signal , is then applied across both of the slots 11-1 and 11-2 on the track 5.

As shown, the slot drive circuit 107 also includes a current sensing circuit 207 which senses the current drawn by the slot cars 3 on each of the slots 11.

This current information is then passed back to the microprocessor 101 for detecting overload conditions caused, by for example, either or both of the slots 11 being short-circuited.

Telemetry Control Module As discussed above, in this embodiment, the telemetry control module 133 records telemetry data for the slot cars 3 as they are raced around the track 5. The amount of telemetry data that is recorded and stored within the main unit 1 is user-defined and in any event is limited by the size of the memory 103. In this embodiment, the main unit 1 is programmed so that it records the telemetry data for each slot car 3 during the whole of a race. At the beginning of the next race, the memory 103 is cleared and the telemetry data for the next race is recorded. Alternatively, the main unit 1 can be programmed (by the user) so

that the telemetry data for the best lap is stored and only overwritten if the user beats the current best lap time.

Figure 8a illustrates in more detail the main components of the telemetry control module 133 used in this embodiment when recording telemetry data during a race. As shown, the telemetry control module 133 includes a telemetry data gathering unit 251 which operates to gather the telemetry data for each of the slot cars 3-1 to 3-6. As shown, in this embodiment, the telemetry data for each slot car 3 includes: the brake control signal (BRK); the speed control signal (SPD); the lane change control signal (LANE); the pit stop control signal (PIT); and the lap control signal (LAP). In this embodiment, the telemetry data gathering unit 251 time-stamps the latest values of the telemetry data as they are received (using a time- stamp generated by a timer 253) and stores the time- stamped telemetry data in the memory 103. The telemetry data gathering unit 251 also receives, at the beginning of the race, race settings data from the function control module 135, which it also stores in the memory 103 together with the telemetry data for the race.

As discussed above, there are various uses for the telemetry data. For example, the telemetry data may be uploaded to the personal computer 15 and then analysed by the user in order to try to find patterns for how they approach each part of the track 5, in order that they can try to improve their racing technique. In this case, the telemetry data from a number of races may be stored within the PC 15 so that the user can also analyse the telemetry data from previous races to determine if they are improving etc.

Alternatively, the recorded telemetry data may be used to automatically drive the slot cars 3 on the track 5 in order to create, in effect, a replay of the race.

Figure 8b illustrates the main components of the telemetry control module 133 used to control this playback of the telemetry data. As shown, the telemetry control module 133 includes an automatic drive controller 255, which operates, when triggered by the timer 253, to retrieve the next telemetry data (defined by the telemetry data time-stamp) for each slot car 3 from memory 103 and to output the retrieved telemetry data to the function control module 135 and the slot car communications control module 139 as

before. At the beginning of the replay, the automatic drive controller 255 also retrieves the race settings for the corresponding telemetry data which it outputs to the function control module 135 for controlling the replay of the race.

As those skilled in the art will appreciate, the ability to automatically drive the slot cars 3 around the track 5 in accordance with stored telemetry data greatly enhances the functionality of the slot car racing system. In particular, users can replay a race (or part of a race) in order to replay the event on the track. Additionally, by using the stored telemetry data from only one of the slot cars 3, the user can race another slot car 3 on the track 5 using one of the hand controllers 7. For example, if the telemetry data is recorded for the best lap time, then the user can race against a slot car 3 driven by the best lap time telemetry data, in order to try to better their (or someone else's) best lap time. The user can, therefore, play with the slot car racing system on their own and still enjoy a two slot car race-by controlling one slot car 3 with the stored telemetry data and by controlling the other slot car 3 with the hand controller 7 in the usual way. In

contrast, with conventional slot car racing systems, at least two players are required in order to have a race.

Slot Car As discussed above, in this embodiment, the slot cars 3 are arranged to receive messages modulated onto the voltage applied to the slots 11 and to be powered from the same voltage. Figure 9 is a block diagram illustrating the main components of the slot car 3 used in this embodiment. As shown, the slot car 3 includes a rectifier and power control circuit 301 which rectifies the bi-polar PWM signal applied to the slots 11 on the track. The rectifier and power control circuit 301 then uses this rectified signal to generate DC power for powering a slot car microprocessor 303. The bi-polar PWM signal received from the slot 11 is also passed to a signal conditioning circuit 305 which converts the bi-polar PWM signal into a corresponding uni-polar PWM signal which can be input to the slot car microprocessor 303.

The slot car microprocessor 303 operates in accordance with software instructions stored in a non-volatile memory 307. In this embodiment, the software controls

the microprocessor 303 to monitor the variation in the PWM signal received from the signal conditioning circuit 305 in order to recover the data packets 200 transmitted by the main unit 1. The microprocessor 303 also checks that there are no errors in each packet 200 using the checksum. byte 204. If there are no errors, then the microprocessor 303 extracts the relevant byte from the message portion 202. This relevant byte is identified by the slot car ID that is also stored in the non-volatile memory 307. For example, if the slot car ID stored in the memory 307 is three, then the microprocessor 303 extracts the third byte from the message portion 202, from which it extracts the speed value (SPD), the brake signal control value (BRK) and the change lane control value (LANE).

In this embodiment, the slot car microprocessor 303 uses the speed control value (SPD) to vary the mark- to-space ratio of a uni-polar PWM signal which it outputs to a motor drive circuit 309. The motor drive circuit 309 amplifies the PWM control signal and then applies it to the DC motor 311 of the slot car 3. In this embodiment, the frequency of the PWM drive signal applied to the motor 311 is fixed at 11.563 kHz and

the mark-to-space ratio is varied between zero (when no current is to be applied to the motor 311) and 1000 (when full current is to be applied to the motor 311).

In this embodiment, when the slot car microprocessor 303 detects that the user has just pressed the brake button 165 (from the value of the brake bit within the appropriate byte of the message portion 202), it outputs a brake control signal to the motor drive circuit 309 which causes the motor drive circuit to apply inverted voltage pulses across the terminals of the motor 311. However, it does so for only a couple of pulses of the PWM control signal, since this is usually enough to stop the slot car 3 on the track 5.

Thereafter, the slot car microprocessor 303 stops outputting the PWM control signal to the motor drive circuit 309 so that the slot car 3 does not move.

Only after the slot car microprocessor 303 receives another data packet 200 from the main unit 1 with the brake bit unset (indicating that the user has released the brake button 165) does the microprocessor 303 resume outputting the appropriate speed control PWM signal to the motor drive circuit 309.

Additionally, in this embodiment, the slot car 3 has

brake lights. 313 at the rear of the slot car 3 which are controlled by a lights control circuit 315, so that when the user presses the brake button 165 these rear brake lights 313 come on and remain on until the user releases the brake button 165 on the hand controller 7. This is achieved by the microprocessor 303 outputting an appropriate control signal to the lights control circuit 315 when it detects the brake bit is set in the received data packet 200.

In this embodiment, when the user wishes to change lane, the slot car microprocessor 303 detects the setting of the change lane bit in the appropriate byte of the message portion 202 and in response outputs a control signal to an opto communications control circuit 313. This opto communications control circuit 313 controls the generation of a light beam by a light emitting diode (LED) 315. In particular, in this embodiment, the opto communications control circuit 313 controls the LED to output pulses of light, whose duration and pulse repetition frequency depend on the slot car ID and whether or not a change of lane is being requested. As will be described in more detail below, the light beam generated by the light emitting diode 315 is detected by a sensor in the track 5 and

used to control a lane change track segment to allow the slot car to change slots 11.

In this embodiment, the opto communications control circuit 313 controls the light emitting diode 315 to continuously generate a light beam which depends upon the slot car ID. This allows the main unit 1 to be able to detect using the sensor signal from the ID detector placed just before the start/finish line, which of the slot cars 3 is about to pass the start/finish line. In this embodiment, the LED 315 is located on the base of the slot car 3 facing the track 5 and is positioned as close as possible to the guide blade (not shown) which is received in the slot 11.

This is because the slot cars 3 have a tendency to slide and twist around the guide blade as the slot car goes round corners. Positioning the LED 315 as close as possible to the guide blade reduces the range over which the LED 315 may move relative to the track 5, which therefore reduces the chances of the LED 315 not passing over the photodetectors provided in the track.

As mentioned above, it is possible to reprogram the slot car ID that is stored in the memory 307. This is achieved by placing the slot car 3 to be programmed on

one of the slots 11 so that its LED 315 is directly over the ID detector provided shortly before the start/finish line. The user then selects the slot car ID (i. e. a value between one and six) using the user input buttons 53 or the connected PC 15. The main unit microprocessor 101 then generates a set car ID message and the new slot car ID is placed in each of the six bytes of the message portion 202. This set car ID message is then used to modulate the voltage applied to the slots 11. The slot car microprocessor 303 then receives the set car ID message and retrieves the new slot car ID value from the message portion 202. This new slot car ID is then stored in the memory 307. The slot car microprocessor 303 also controls the opto communications control circuit 313 so that the LED 315 outputs pulses of light indicative of the new slot car ID. These light pulses are then detected by the ID detector that the slot car 3 is currently positioned over and fed back to the ID co- processor 108. In this way, the main unit microprocessor 101 will receive verification that the slot car 3 has been reprogrammed with the new slot car ID and in response outputs a signal to the user on the LCD display 51 confirming that the reprogramming has been successful.

In this embodiment, the slot car 3 is arranged so that it can also run on a conventional analogue-type slot car racing system. This is achieved by the slot car microprocessor 303 processing the signal received from the slot 11 to determine whether or not it carries data transmitted from the main unit 1. If it does not, then the slot car microprocessor 303 outputs a control signal to the rectifier and power control circuit 301 to cause it to pass the electrical current received from the slot 11 directly to the slot car motor 311. Provided there is sufficient current on the slot 11, the rectifier and power control circuit 301 continues to provide power to the slot car microprocessor 303 which continues to process the slot signal to determine if it contains any data. Once the slot car microprocessor 303 detects a data packet 200 it outputs a control signal to the rectifier and power control circuit 301 to stop it passing the current directly to the slot car motor 311. Instead, the slot car microprocessor 303 uses the speed value in the received packet 200 to generate an appropriate PWM speed control signal as before. In this way, the slot car 3 can operate both in the new digital slot car system of the present embodiment or in a conventional

analogue-type slot car system.

Change Lane Track Segment As discussed above, in this embodiment, the slot cars 3 are able to change slots 11 on the track 5. To do this, a number of change lane track segments are provided on the track 5 which connect the slots 11 together. Figure 10 schematically illustrates the form of a change lane track segment 351 that is used in this embodiment for allowing a slot car 3 to change from slot 11-1 to slot 11-2. A similar change lane track segment 351 will be provided for allowing slot cars 3 to change from slot 11-2 to slot 11-1. As shown in Figure 10, the track segment 351 includes two slots 11-1 and 11-2 and a branch slot 353 for allowing slot cars 3 on slot 11-1 to change onto slot 11-2, which is controlled by a gate 355. The position of the gate 355 is controlled by a gate controller module 357 which, in this embodiment, is located to the side of the track 351. As represented by the connectors 359, the gate controller module 357 is powered by the voltage on the slot 11-1. Figure 10 also shows the photodetector 361 which senses the optical change lane requests transmitted by the slot cars 3. As shown, the photodetector 361 is provided under the slot 11-1

shortly before the gate 355. As represented by the connector 363, the photodetector 361 is connected to the gate controller module 357 which receives the signal from the photodetector 361 and which determines whether or not the slot car 3 currently passing over the photodetector 361 is transmitting a request to change lane. If it is, then the gate controller module 357 outputs an appropriate control signal to the gate 355 to open the gate 355 into the position shown in Figure 10. In this case, the slot car 3 will pass along the branch slot 353 to the other slot 11-2.

If the slot car 3 does not want to change lane, then the gate controller module 357 ensures that the gate 355 is in the position represented by the dashed line so that the slot car 3 continues along the slot 11-1.

The particular gate mechanism used in this embodiment is illustrated in Figure 11. In particular, Figure lla schematically illustrates the slot 11-1 and the branch slot 353 in dashed lines. Figure lla also shows the gate 355 in the form of a triangular block which is mounted on a flat slider 369 which fits below the slot 11 and which is moved from side to side by two solenoids 371 and 373. The gate controller module 355 controls the solenoids 371 and 373 so that they

operate in a"push-pull"arrangement whereby when energised, solenoid 373 pushes the gate 355 and solenoid 371 pulls the gate 355. Figure lla illustrates the position of the gate 355 when a change lane request is not received and the slot car 3 is to continue along the slot 11-1. In this configuration, the solenoids 371 and 373 are not energised and the gate 355 is positioned in the branch slot 353, thereby preventing the approaching slot car 3 from changing lane. In contrast, as shown in Figure llb, when a lane change request is received, the solenoids are energised and solenoid 371 pulls and solenoid 373 pushes the slider 369 to the left,. thereby moving the gate 355 into the slot 11-1 causing the approaching slot car 3 to be directed onto the branch slot 353 towards the other slot 11-2.

Gate Controller Module Figure 12a is a block diagram illustrating the main components of the gate controller module 3.57 used in this embodiment. As shown, in this embodiment, the gate controller module 357 includes a microprocessor 375 which operates in accordance with software stored in non-volatile memory 377. The gate controller module 357 also includes a rectifier and power control

circuit 379 which rectifies the bi-polar PWM signal on slot 11-1 to provide power for the microprocessor 375.

The gate controller module 357 also includes a photodetector interface 381 which receives the signal from the photodetector 361 and passes it to the lane change microprocessor 375. The lane change micro- processor 375 processes the signal from the photodetector interface 381 to determine whether or not the current slot car 3 passing over the photodetector 361 wishes to change lane. If the slot car 3 does not wish to change lane, then the lane change microprocessor 375 takes no action and the solenoids remain in their de-energised state (illustrated in Figure lla) so that the slot car 3 continues along the slot 11-1. If, however, the lane change microprocessor 375 detects that the slot car 3 does wish to change lane, then it outputs appropriate control signals to two solenoid drive circuits 383-1 and 383-2 for energising the two solenoids 371 and 373. This causes the solenoids to move the gate 355 into the position shown in Figure llb, thereby causing the approaching slot car 3 to be directed down the branch slot 353 towards the other slot 11-2. Once the slot car 3 has passed the gate 355, the lane change microprocessor 375 outputs control signals to the

solenoid drive circuits 383 to deactivate the solenoids 371 and 373, thereby returning the gate 355 to the position shown in Figure lla.

SLOT CAR TO TRACK COMMUNICATIONS As mentioned above, in this embodiment, each of the slot cars 3 is arranged to emit from their LED 315 pulses of light whose duration and pulse repetition frequency depend on the slot car ID and whether or not the slot car 3 wishes to change lane. The photodetector 361 (and the ID detectors at the start/finish line) will therefore output voltage pulses whose durations correspond to the duration of the light pulses generated by the passing slot car 3.

Figure 12b is a time plot illustrating the possible outputs from a photodetector under the track 5. As can be seen from Figure 12b, each of the slot cars 3 is arranged to continuously transmit pulses of light at a pulse repetition frequency depending on their car ID. In this embodiment, for the first slot car 3-1 this is 5.683 kHz decreasing to 2.525 kHz for the sixth slot car 3-6. As shown in Figure 12b, when the slot cars 3 do not want to change lane, the duration of the transmitted pulses is much longer (in this embodiment at least three times longer) than the

pulses transmitted by the slot cars 3 when they do want to change lane.

With the above minimum pulse repetition frequency, the lane change microprocessor 375 and the slot car ID co- processor 108 will therefore receive at least four voltage pulses when a slot car 3 passes over the corresponding photodetector. The change lane microprocessor 375 can therefore use the timings of all of the received pulses to accurately measure the duration of the pulses. The lane change microprocessor 375 then compares the determined duration with a threshold value associated with a change lane request (which is stored in the non- volatile memory 377) to determine whether or not the slot car 3 passing over the photodetector 361 wishes to change lane. In a similar way, the slot car ID co- processor 108 uses the timings of all the received pulses to accurately measure the pulse repetition frequency of the pulses which it compares with expected pulse repetition frequencies associated with the slot car IDs, to determine which slot car 3 is currently passing over the ID detector. The slot car ID co-processor 108 then passes this slot car ID information to the microprocessor 101.

Accessory Unit As discussed above, the main unit 1 has an accessory unit interface 117 for allowing an accessory device to be connected to the main unit 1. Various different types of accessories can be used. For example, a gantry of lights may be provided at the start/finish line which can be connected to the main unit 1 via the accessory unit interface 117. Instead of such a gantry, a communications accessory may be. connected to the accessory unit interface 117 which allows the main unit 1 to directly connect to a data network (such as a LAN or the internet) without having to connect via the PC 15. Such a communications accessory module allows users that do not have personal computers to be able to connect to a data network and therefore be able to transmit telemetry data to and receive telemetry data from remote users. The accessory units will include a microprocessor and a bus and will communicate with the microprocessor 101 in the main unit 1 via the data bus 111.

Personal Computer As discussed above, the main unit 1 includes a PC interface 115 for connecting the main unit 1 to a

personal computer 15. This allows the telemetry data gathered by the main unit 1 to be passed to the personal computer 15 and used to create a virtual simulation of a real race-or to control a virtual race on the display of the personal computer 15. Further, since the personal computer 15 includes internet access, the connection to the personal computer 15 also allows the telemetry data to be transmitted to a remote user, either for remote simulation or for automatically controlling the driving of slot cars 20 on a remote track 21. Similarly, telemetry data transmitted from a remote location can be received by the personal computer 15 and used either to generate a local virtual simulation on the display of the personal computer 15 or to drive the appropriate slot cars 3 around the local track 5.

Figure 13 schematically illustrates the main components of the personal computer 15 used in this embodiment. As shown, the personal computer 15 includes an interface and pre-processing module 401 for connecting to the PC interface 115 of the main unit 1. The interface and pre-processing module 401 passes the telemetry data to application logic 403 which can:

1) use the telemetry data to drive a virtual simulation of the real race; 2) store the telemetry data in a race data file for subsequent analysis by the user; 3) output the telemetry data for transmission to a remote user; or 4) use the telemetry data to control a virtual race.

As shown in Figure 13, the application logic 403 is therefore connected to a user interface 405 which generates and displays the virtual simulation/race or which displays the race analysis data to the user; and to an internet interface 407 which makes the connection to the remote user over the internet 19.

A more detailed description of the interface and pre- processor module 401, the application logic 403 and the user interface 405 will now be given.

Interface and Pre-processor Figure 14 is a block diagram illustrating the main components of the interface and pre-processor module 401 shown in Figure 13 As shown, the interface and pre-processor module 401 includes a communications

control module 415 for controlling communications with the main unit 1 ; an application logic interface 417 for providing the interface with the application logic 403; and a main unit co-processor 421.

Co-processor In this embodiment, the main unit co-processor 421 is provided in order to take advantage of the processing power of the personal computer 15 and to remove some of the processing burden on the main unit microprocessor 101. Various different functions can be performed by the main unit co-processor 421, with the results being transmitted back to the main unit 1 as appropriate. For example, as discussed above, the users can press buttons on their hand controllers 7 to emulate pit stops that are required under the rules of the race. The co-processor 421 may be arranged to monitor for these pit stops and, if they are not taken, to output control signals back to the main unit 1 in order to limit the speed or to stop the slot car 3 that has not taken the necessary pit stops. Similarly, the co-processor 421 can be configured by the user so that one or more of the slot cars 3 has a speed limit. In this case, the co-processor 421 monitors the telemetry data for the selected slot car

3 and transmits speed control signals back to the appropriate microprocessor 101 when the received speed data reaches the maximum speed, to ensure that the speed of the slot car 3 is not increased further.

This is useful for younger children and novices who are unable to control the speed of the slot cars 3 on the track 5 to prevent the slot cars 3 leaving the track 5. As a result, the new slot car racing system is more appealing to user's of all ages and experience.

As those skilled in the art will appreciate, the above examples of operations by the co-processor 421 are given by way of example only. Various other uses of the co-processor 421 will be apparent to those skilled in the art.

Application Logic As discussed above, the purpose of the application logic is to provide analysis tools for allowing users to analyse stored telemetry data from previous races and to provide a virtual simulation of a real race or to control a virtual race on the display screen of the personal computer 15. The application logic also allows the user to set up the various race parameters that can be set up using the input buttons 53 on the

main unit 1. Finally, the application logic controls the transmission and reception of telemetry data to/from a remote terminal via the internet 19.

Figure 15 is a schematic block diagram illustrating the main components of the application logic 403 shown in Figure 13. As shown, the application logic 403 includes an application logic control module 601 which receives the telemetry data from the interface and pre-processor module 401. The telemetry data for slot cars 3 on the track 5 is passed by the application logic control module 601 to a race simulation module 603 which operates like a conventional racing computer game in that it uses a predetermined model (not shown) which relates the hand controller signals to a change in position of a virtual car on a virtual track. The race simulation module 603 then outputs the appropriate position data together with track layout data and scenery data from the track layout and scenery data store 605, to the user interface 405 which uses the data to generate an appropriate virtual simulation of the race.

In this embodiment, during a race, the application logic control module 601 also passes the telemetry

data for each slot car 3 to a race file generator 606 which opens a race file and stores the data in the race file within the race file data store 607. In this embodiment, the race file is stored as a continuous time based sequence of telemetry data together with data that identifies the racing mode and the slot cars 3 that are used. The data files that are stored in the race file data store 607 can then be retrieved by the user via the user interface 405 and used to generate a virtual simulation of the race using the race simulation module 603. The race file may also be passed back to the main unit 1 to control the driving of one or more of the slot cars 3 on the track 5. Alternatively, the race file may be passed to a race analysis module 609 which can perform various different processings on the data (in accordance with user interaction via the user interface 405) in order to analyse the user's performance during the race. For example, if the telemetry data is for a multi-lap race, then the race analysis module 609 can calculate the average lap time, the best lap time, the best time through a particular portion of the track etc. The user can also compare their race statistics with the race statistics for other users on the local track 5 or for users on remote tracks 21.

As discussed above, the application logic 403 controls the transmission and reception of telemetry data over the internet via the internet interface 407. In this embodiment, the telemetry data can be streamed to a remote user substantially in real time using an internet streaming module 611. In this case, the telemetry data received by the application logic control module 601 is immediately passed to the internet streaming module 611 with the appropriate internet address for the remote terminal. The internet streaming module 611 then uses the received data to generate a corresponding stream of data packets which it outputs to the internet interface 407 for onward transmission to the remote terminal.

Alternatively, the application logic control module 601 can retrieve one or more of the race files stored in the race file data store 607 and forward this to the remote terminal using an internet file transfer module 613. As those skilled in the art will appreciate, a separate streaming module 611 and file transfer module 613 are required since different transmission protocols are used depending on if the data is being streamed (for real time use at the receiving terminal) or if a file transfer is being

made (in which case real time transmission is not essential).

Similarly, if the internet streaming module 611 or the internet file transfer module 613 receives telemetry data from a remote terminal, this data is passed to the application logic control module 601. In response, depending on the current race mode of the main unit 1, the application logic control module 601 either: (i) passes the received telemetry data to the race file generator 606 for storage in the race file data store 607; (ii) passes the received telemetry data to the race simulation module 603 to create an appropriate virtual simulation of a race (so that local users can have a virtual race with remote users); or (iii) passes the received telemetry data back to the interface and pre-processor module 401 for onward transmission to the main unit 1 for use in driving one or more of the slot cars 3 on the track 5.

Finally, as shown in Figure 15, the application logic 403 also includes a race setup graphical user interface (GUI) module 615 which allows the user to set up the various race modes that are available using the personal computer 15 instead of the user interface

on the main unit 1 formed by the input buttons 53 and the LCD display 51. The race setup GUI module 615 also allows the user to define the current layout of the track 5 and the type of scenery to be used in the simulation (e. g. city, alpine, winter etc). This track layout and scenery data is then passed back to the application logic control module 601 which stores the data in the track layout and scenery data store 605. The race setup GUI module 615 also allows the user to set the hand controller function (f (0)) used to relate the determined hand controller throttle position to the desired speed value In the example shown in Figure 5b, this function is linear. The race setup GUI module 615 can be used to vary the gradient of the function or to define other non-linear functions such as exponential or piece-wise linear functions, as appropriate. In this way, the user can experiment with different hand controller characteristics and then compare the telemetry results using the race analysis module 609 to determine the best hand controller function for them. Any race configuration data generated by the user using the race setup GUI module 615 is then passed back to the application logic control module 601 for onward transmission back to the main unit 1 via the interface

and pre-processor module 401.

User Interface As discussed above, the position data and the track. data output by the race simulation module 603 are passed to the user interface 405 for generating the appropriate virtual simulation of the real race or the appropriate virtual race. As shown in Figure 16, in this embodiment, this virtual simulation/race is generated by a rendering engine 631 which, in this embodiment, is a standard rendering engine commonly used in 3-D computer games. The rendering engine 631 uses the positional information and the track layout and scenery data received from the race simulation module 603 and generates an appropriate current screen image which it outputs to the frame buffer 633 for display on the display 635. The image data stored in the frame buffer 633 is then recalculated/updated by the rendering engine 631 using the next received position and track layout and scenery data received from the race simulation module 603 etc. , to create a moving image 3D simulation of the actual slot cars 3 racing on the track 5 or to create a moving image 3D virtual race.

As shown in Figure 16, the frame buffer 633 can also receive images generated by the race analysis module 609 and the race setup GUI module 615. These images are also displayed on the display 635 and any user input generated in response is detected by a user input device 637 (e. g. keyboard or mouse) which is then passed back to the application logic 403.

Modifications and Alternative Embodiments A new digital slot car racing system has been described above. As those skilled in the art will appreciate, various modifications can be made to the above slot car racing system whilst achieving many of the advantages associated with it. Some of these modifications and alternatives will now be described.

In the above embodiment, a digital slot car racing system was described in which a main unit transmitted speed control messages to the slot cars racing on the track. Novel slot cars were therefore provided which could receive the communications from the track and control the application of power to their motor accordingly. These new slot cars were also configured to be able to work with existing analogue type slot

car systems in which the electrical current applied to the slot is used to directly drive the motor in the slot car. In this case, the signal received by the slot car is output from the rectifier and power control circuit directly to the slot car motor. As those skilled in the art will appreciate, this new slot car will be relatively expensive because of the additional electronic circuits required. Since most slot car enthusiasts normally buy several slot cars, these additional electronic circuits are preferably provided in a retractable module which can be moved from slot car to slot car. This is illustrated in Figure 17 which shows a slot car 3, the slot car motor 311, the lights 313 provided at the rear of the slot car and the removable in-car module 319 housing the electronics and the light-emitting diode 315. The electronic components in the in-car module 319 are shown within the dashed box also labelled 319 in Figure 9. As also shown in Figure 9, the in-car module 319 includes terminals 320a and 320b for connection to the terminals on the guide blade 321 (shown in Figure 17). Similarly, the in-car module 319 also includes a terminal 322 for connecting the lights control circuit 315 to the slot car lights 313.

Finally, the in-car module 319 includes terminals 324a

and 324b for connecting the slot car motor 311 to the motor drive circuit 309.

Preferably, as illustrated in Figure 18, a"dummy"in- car module 319'is also provided which can be installed in slot cars 3 that do not have the digital in-car module 319 installed. As shown in Figure 18, in this dummy in-car module 319', the terminals 320 for connection to the slot car guide blade 321 are directly connected (by conductors 325 and 327) to the terminals 324 for connection to the slot car motor 311. In this way, the slot car 3 with the dummy in car module 319'can still be used with existing analogue-type slot car systems in which the electrical current applied to the slot is used to directly drive the slot car motors 311.

In addition to the above in-car modules, the applicant intends to sell a retro-fit kit which will allow enthusiasts to be able to adapt existing analogue-type slot cars so that they are suitable for use in this new digital slot car system. This retro-fit kit will include an appropriate printed circuit board having the microprocessor and the other electronic circuits shown in the dashed box 319 of Figure 9 and will

provide the necessary connectors for connecting the circuit board to the slot car guide blade 321, the motor 311 and any slot car lights 313.

In the above embodiment, and as illustrated in Figure 11, a triangular gate which moved from side to side was used to control lane changes of the slot cars. An alternative design of the change lane gate is shown in Figure 19. In particular, Figure 19a is a cross- sectional view of the gate and Figure 19b is a plan view. As shown in Figure 19b, the alternative gate 355 is pivotally connected to the slider 369 at pivot 356 and pivotally connected to the track 5 at the pivot 358. In this way, when solenoid 373 is energised to pull the slider 369 to the right, the gate 355 pivots about pivot 358 closing the branch slot 353. Similarly, when solenoid 371 is energised and the slider 369 is pulled to the left, the gate 355 will pivot to the left (as shown in phantom) about pivot 358 causing the slot car 3 to pass down the branch slot 353.

Figure 19b also shows in more detail the form of the solenoids 371 and 373 used to move the gate 355. In particular, Figure 19b shows the two solenoid coils

379 and 381 and the metallic plungers 375 and 377 which are received in the coils 379 and 381. As discussed above, the solenoids 371 and 373 and the solenoid drive circuits 383 are arranged so that the solenoids 371 and 373 are driven in a push-pull manner. This allows the quick and efficient driving of the gate 355 between the non-change lane and the change lane positions.

In the above embodiment, the change lane track segment included both the slot car photodetector 361, the control module 357 and the change lane gate 355. Such an arrangement is relatively costly if the user wishes to buy separate change lane track segments for different scenarios, such as a change lane on a left- hand bend, a change lane on a right-hand bend etc. It is therefore preferable to separate the track segments which operate to detect the change lane request and the segments which include the change lane gates.

Such a modular arrangement is illustrated in Figure 20. In particular, Figure 20 includes a first track segment 701 which includes the photodetectors 361-1 and 361-2 provided on each slot. These photodetectors output their signals to a change lane detector module 705 which monitors for the change lane requests

emitted by the slot cars. This detector module 705 is powered from one of the slots. This first detector track segment 701 and detector module 705 are designed to interface with a change lane track segment 703 and to a change lane controller 707 respectively. In the illustrated embodiment, the change lane track segment 703 is a track segment which allows slot cars on either slot to change lane on a right-hand bend. The change lane controller 707 is operable to receive control instructions from the detector module 705 and to output appropriate control signals to the gate solenoids 709 and 711 for controlling the lane changes on the two slots. The lane change controller 707 can also receive its power from the detector module 705 or from one of the slots. The interface connecting the detector module to the lane change controller 707 may be provided by a flying lead type connector or by conductors embedded in the track.

As those skilled in the art will appreciate, the above modular approach is more cost effective for the user since the expensive microprocessor and other circuitry is only needed in the detector module 705 whereas relatively inexpensive solenoid drive circuits are required in the change lane controllers 707. The user

can therefore buy a limited number of detector track segments 701 and detector control modules 705 but can buy many different types of change lane track segments 703. As a result, the user has increased flexibility in the design and layout of the track without the added cost.

In the above embodiment, the change lane controller was provided to the side of the slot car track. In an alternative embodiment, the electronics for the change lane controller may be provided underneath the playing surface of the slot car track so that they are not visible to the user.

In the above embodiment, the hand controller was arranged so that the value of the hand controller voltage was unique for any throttle position regardless of the status of the user control buttons.

As those skilled in the art will appreciate, this is not essential. However, if there is not a one-to-one correspondence between the input voltage and the throttle position and button status, then the H/C control module will have to track changes of the input voltage to detect sudden changes in the input voltage indicating button presses. By ensuring that the

change in voltage is different for each combination of button presses, the H/C control module can still determine the throttle position and the status of each control button.

In the above embodiment, the slot cars varied the duration of light pulses that they transmit to the track, depending on whether or not they wish to change lane. Additionally, the pulse repetition frequency of these pulses was varied depending on the slot car ID for the slot car. As those skilled in the art will appreciate, other encoding techniques can be used to encode this information onto the voltage pulses. For example, each slot car may be programmed to transmit pulses at a constant pulse repetition frequency but with two different durations, depending on whether or not a lane change is being requested. Further, provided each slot car transmits pulses of different durations, the slot car ID co-processor can still determine which slot car is about to pass the start/finish line from the measured pulse duration.

In the above embodiment, the user was able to set the number of pit stops that each slot car has to take during a race. The main unit was then operable to

monitor for these pit stops to ensure that they were taken and, if they were not taken to penalise the slot cars accordingly. In the above embodiment, the user took a pit stop by stopping the slot car and by pressing both of the buttons on the hand controller.

In an alternative embodiment, separate pit lanes may be provided from each slot which can be accessed via an appropriate change lane track segment. In such an embodiment, the user simply requests a change lane shortly before the pit lane which will cause the user's slot car to enter the pit lane. The controller associated with the changed lane gate for entering into this pit lane can then inform the main unit which slot car has just entered the pit lane.

Alternatively, a separate optical sensor may be provided in the pit lane which is directly connected to the main unit and which detects the slot car ID signal transmitted by the slot car. In either event, the main unit will be informed when each slot car enters the pit lane and subsequently exits the pit lane. The main unit can therefore ensure that each slot car takes the necessary pit stops and can penalise slot cars that do not take the necessary pit stops.

In the above embodiment, the main unit transmitted data to each of the slot cars. As those skilled in the art will appreciate, it is possible to provide a back channel from each of the slot cars to the main unit. This back channel can be implemented, for example, by the slot cars short-circuiting the slot in accordance with the data to be transmitted to the main unit or by the slot cars applying a high frequency signal to the track which can then be detected by the main unit. This back channel can be used to provide various additional telemetry data such as the back EMF of the slot car motor as measured by an appropriate sensor on the slot car.

In the above embodiment, the slot cars included an LED which emitted a slot car ID and, any request for changing lane. The slot car ID was sensed by the main unit as the slot cars were about to pass the start/finish line and used to maintain lap times for each slot car. In the above embodiment, however, the change lane microprocessor did not use the slot car ID information received from the photodetector. In an alternative embodiment, the change lane microprocessor may also be programmed to use the slot car ID data as well. For example, the change lane microprocessor may

be arranged to limit the number of lane changes each slot car is allowed to take either during a race or in a predefined time. In such an embodiment, the lane change microprocessor is also preferably able to communicate with the main unit. This can be achieved, for example, by adding additional bytes to the data transmitted on the slots which are addressed to the or each change lane microprocessor. This additional data can be used, for example, to inform the change lane microprocessor when the start of the race occurs and how many change lanes each slot car is allowed to have.

In the above embodiment, the slot cars communicated their desire to change lane to the change lane controller at the side of the track by emitting a light beam to a photodetector in the track. As those skilled in the art will appreciate, a similar change lane arrangement can be provided by providing some other mechanism for the slot car to communicate with the change lane unit. For example, an RF or an acoustic transmitter may be provided in the slot car which can transmit its desire to change lane to a suitable receiver of the change lane controller.

Alternatively still, a mechanical arrangement may be

provided which is deployed when the slot car wishes to change lane. For example, when the slot car receives the change lane request from the main unit, it can deploy a mechanical arm from the side of the slot car which when deployed, can interact with a switch at the side of the track. This can then be detected by the change lane controller and used to control the change lane gate. Various other arrangements will be apparent to those skilled in the art.

In the above embodiment, the slot car was arranged to transmit its ID and change lane request by varying the duration of the light pulses emitted by its light emitting diode. As those skilled in the art will appreciate, other modulation techniques can be used to convey this data to the change lane controller.

However, the technique described above is preferred because it reduces the complexity of the slot cars and the detectors that operate to sense the light emitted by the slot cars.

In the above embodiment, the main unit interfaced with a personal computer which allowed a virtual simulation or a virtual race to be displayed to the user on the screen of the personal computer. As those skilled in

the art will appreciate, it is possible to connect the main unit to other computer devices such as a games console or the like. In this case, the games console would create the appropriate signals for output on an attached display or television screen.

In the above embodiments, the user could transmit or receive telemetry data to/from a remote user so that they can race against the remote user. In view of the relatively large amount of telemetry data that has to be transmitted in order to control a slot car on the track, in an alternative simpler embodiment, each of the users could transmit timing information (e. g. lap times or the times at which they pass predetermined points on the track) to a central server. The central server can then compare the lap times to identify the positions of the slot cars in the race and timing information that identifies the gap between the different users'slot cars in the race. The central server can then transmit this information back to each user's personal computer and/or main unit. In this case, the user may be provided with feedback about the position of the other user's car either as a visual output on the display of the personal computer or as an audible output to advise them who is winning the

race.

Additionally, in an embodiment where such a central server is provided, users can upload telemetry data for a lap or race to the server, so that other users can download it to try to better the results. This leads to a situation where it is possible to organise a race with many thousands or millions of users participating. In particular, provided each of the users has the same track layout, they can each race a slot car on their track and generate telemetry data or at least lap time data which can then be transmitted to the central server. The central server can then identify the user with the best lap time as the winner of the race. Alternatively, the central server can stream the telemetry data for the best user (s) to each user's personal computer which can use the data to generate a virtual simulation to show where the best racers are in the race compared to the local user.

Instead of streaming the data from the central server, the central server can also provide telemetry data files for the users to download for later use in controlling the virtual simulation or for use in driving a slot car on the user's track.

In the above embodiment, the slot cars controlled the speed of their motor by applying a pulse width modulated current signal to the motor. The advantage of this is that there are periods within the driving signal when no current is applied to the track during which the back EMF of the slot car motor can be measured. However, this is not essential, instead, a conventional DC control current may be applied in an alternative embodiment.

In the above embodiment, a hand controller was described which connected to the main unit using only two wires and which allowed the encoding of a throttle position as well as other control inputs. This was achieved by using a variable resistor and a couple of user actuable switches which changed the resistance of the electrical elements in the hand controller. As those skilled in the art will appreciate, other arrangements are possible which can achieve the same result. For example, instead of varying the resistance of the electrical elements in the hand controller, the user switches and throttle may be used to vary the resistance and/or the reactance (capacitance and/or inductance) of elements in the hand controller. In such an embodiment, as the user varies the throttle

position, the impedance of the circuit elements in the hand controller would continuously vary with the throttle position. Similarly, when the user presses one of the control buttons on the hand controller, this will result in a step change in the impedance of the circuit elements in the hand controller. The hand controller control module can therefore detect the present throttle position and the status of the switches by monitoring variations in the impedance of the circuit elements in the hand controller.

In the above embodiment, the main unit connected to the track via a separate base unit. As those skilled in the art will appreciate, this is not essential.

However, it is preferred since it facilitates the connection of the main unit to the PC, especially when the PC is in another room to the track. However, in an alternative embodiment, the main unit may connect directly to the track and need not be able to interface with the PC.

In the main embodiment described above, a new digital slot car racing system was described. The system was adapted to be able to work with existing track. The separate components of the system, such as the main

unit and base unit and the hand controllers may be made and sold separately from the track and the slot cars.

In the above embodiment, the main unit, the slot cars and the change lane controllers were all microprocessor-based devices which are controlled by software stored in an internal memory. As those skilled in the art will appreciate, the microprocessor in these devices may instead be formed from separate dedicated hardware circuits which perform the functions discussed above. However, software is preferred, since the software modules can be upgraded to improve the performance and to add functionality.

The software for controlling these microprocessor may be obtained by downloading it from a remote server or it may be provided on a computer readable medium such as a computer disc or a CDROM. Similarly, the control software used for controlling the personal computer 15 may be downloaded as a signal from a remote server or provided on a computer readable medium such as a floppy disc, CDROM or the like.