The invention is hereinafter described with reference to model racing cars which run round an endless track in at least sets of two and are designed to race one another. Many examples of such systems can be found. Despite the particularity of the following description, it is to be appreciated that the present invention also applies to model railway sets, and, indeed, any other electrically powered model devices.

United States patent No 5749547 granted 12 May 1998 shows a means of controlling a model vehicle on a track, in this example a model train on a train track. The invention discloses a controller which causes a direct current control signal to be superimposed on alternating current power signals during periods of zero crossing of an AC waveform used to power the train propulsion. The direct current control signals controlling effects and features on the model train. The train includes a receiver unit responsive to the direct current control signal.

In the scheme proposed in United States patent No 5749547 the vehicle (the model train) is required to be AC powered which can add to the complexity, the simplest and most common means of powering (ie moving) a vehicle using a simple DC motor. The system comprises a hand held remote transmitter for transmitting user input signals to a receiver unit which generates direct current control signals, coupled to the model train track to be received at the model train to control ancillary features of the first model train. A second model train is controlled using electromagnetic control signals.

Features on the model train include a horn and a whistle. The DC

control signals can also be used to control the speed of the model train.

The present invention provides a method and apparatus for use in the system where features on a model vehicle, in the example given a model car, can be maintained in constant operation despite variation of a power supply to a model vehicle. The present invention further seeks to provide freedom to apply any control signal to any vehicle or trackside utility to perform any operation. The present invention yet further seeks to provide total backward compatibility between any existing model vehicle track and any model vehicle adapted to correspond with the improved features of the present invention.

According to a first aspect, the present invention consists in a method of providing operating power in a model vehicle track where model vehicle moving power is provided to the track as a variable voltage, said method comprising the steps of: generating a high frequency waveform ; adding said high frequency waveform to the variable voltage on the track; at the track, separating said high frequency waveform from the variable voltage ; and rectifying said high frequency waveform to provide operating power.

According to a second aspect, the present invention consists in a model vehicle track comprising: means to provide vehicle moving power as a variable voltage ; means to generate a high frequency waveform; means to add said high frequency waveform to said variable voltage; means, at said track, to separate said high frequency waveform from said variable voltage ; and means to rectify said high frequency waveform to provide operating power.

According to a third aspect, the present invention consists in a method of controlling a model vehicle track where a model vehicle primary power is provided to the track in the form of a motive voltage, said method comprising the steps of: generating a signalling waveform; adding said signalling waveform to the motive voltage on the track; in a model vehicle on said track, separating

said signalling waveform from the motive voltage; decoding the signalling waveform to determine if the signalling waveform represents a command for that model vehicle ; and obeying the command if the signalling waveform proves to be representative of a command for that model vehicle.

The invention also provides that the motive voltage can be provided in the form of a variable voltage, and that the method can include the further steps of: generating a high frequency waveform; adding said high frequency waveform to the variable motive voltage on the track; at the track, separating said high frequency waveform from the variable motive voltage; and rectifying said high frequency waveform to provided operating power.

The invention also provides that rectification of the high frequency waveform can include voltage multiplication.

The invention further provides that the signalling waveform can be used to address one or more functions in any one of a plurality of model vehicles, and that the one or more functions can include at least one of: the speed of the or each model vehicle; the direction of the or each model vehicle ; the operation of one or more lights ; the intensity of one or more of the lights; the operation of one or more sound effects; and the intensity of one or more of the sound effects.

The present invention further provides that the variable voltage can be AC or DC.

The invention further provides that the high frequency waveform can be of low amplitude, and that rectification of the high frequency waveform can include voltage multiplication, preferably doubling, so to reduce electromagnet interference.

The present invention further provides that the operating power can be applied to light one or more lights on a model vehicle.

The invention further provides that the operating power can be used on a model track vehicle.

The invention further provides that the operating power can be used on a trackside utility.

The invention further provides that the operating power can be applied to operate a controller, and that the controller can be used to obtain input from sensors, and to operate items.

The invention further provides that the controller can be used on a model track vehicle.

The invention further provides that the controller can be used on a trackside utility.

The invention further provides that a sensor can be an acceleration sensor, and that the acceleration sensor can comprise a magnetic conductive moveable object (preferably a ball bearing) in a tube, the tube being mounted with a fore and aft component in a model vehicle, the object being biased to the centre of the tube by a magnet, and the object being urged by acceleration to a first end of the tube to complete a circuit to signal acceleration.

The invention further provides that an operated item can be a car engine noise generator, responsive to the acceleration sensor.

The invention further provides that a sensor can be a deceleration sensor, and that the deceleration sensor can comprise a magnetic conductive moveable object (preferably a ball bearing) in a tube, the tube being mounted with a fore and aft component in a model vehicle, the object being biased to the centre of the tube by a magnet, and the object being urged by deceleration to a second end of the tube to complete a circuit to signal deceleration.

The invention further provides that an operated item can be a car brake noise generator, responsive to the deceleration sensor.

The invention further provides a sensor can be a turn sensor, said turn sensor comprising a magnetic conductive moveable object (preferably a ball bearing) in a tube, the tube being mounted with a transverse component in a model vehicle, the object being biased to the centre of the tube by a magnet, the object being urged by centripetal force to a first end of the tube to complete a circuit to signal a right turn, and the object being urged by centripetal force to a second end of the tube to complete a circuit to signal a left turn.

The invention further provides that an operated item can be a car tyre noise generator, responsive to the turn sensor.

The present invention further provides that a model vehicle can comprise a collision sensor, and that the controller can modify the performance of the model vehicle in response to its perceived degree of damage.

The invention further provides that the acceleration sensor can be a part of the deceleration sensor and vice versa.

The invention further provides that the controller can employ a low voltage sensor, operative to detect when the operating voltage is less than a predetermined voltage and operative to reset the operation of the controller in response thereto.

The invention further provides that the high frequency signal can be pulse width modulated and/or amplitude modulated to indicate a value for a first variable quantity to be used by at least one of a model track vehicle and a trackside utility, and/or that the high frequency signal can be frequency modulated to indicate a value for a second variable quantity to be used by at least one of a model track vehicle and a trackside utility.

The invention further provides that informational and command signals can be added to the variable voltage and to the high frequency waveform on the track to command and control at least one of a model track vehicle and a trackside utility.

The invention further provides that the information and command signals can have a frequency which is higher than the frequency of said high frequency waveform.

The invention further provides that a model vehicle can detect and interpret input from one or more passive track items, and that the passive track items can include at least one of a speed indicating strip, a bar code, a magnet, and a light source.

The invention further provides that a trackside utility can detect and interpret input derived from passage of vehicles, and that input derived from passage of vehicles can include at least one of the speed of vehicle and the position of a vehicle.

The invention further provides that the track can be a model railway track.

The invention further provides that the track can be a model car track.

The invention further provides that the model car track can comprise one or more electrical sockets, each co-operate with an electrical plug, to convey the high frequency signal to a trackside utility and which can also be used to support the trackside utility.

The invention is further explained, by way of example, by the following description, to be read in conjunction with the appended drawings, in which: Figures 1A to 1D show schematic electrical diagrams illustrating how a model car racing track is currently powered according to the

present and prior art, employing a variable voltage source to drive the model racing car.

Figure 2A shows a plan view of an exemplary model car racing track according to the present and the prior art.

Figure 2B shows a side, cutaway view of an exemplary model racing car on a track, illustrating how, according to the present and prior art, electrical energy is derived from the track of Figure 2A, how a motor is powered, and how accessories such as lights are also powered.

Figure 3 is an electrical schematic diagram showing a power supply for the model car racing track, otherwise shown in Figures 2A and 2B, incorporating a high frequency waveform to be included with the variable voltage which, according to the present and prior art, is used to drive the motor on a model racing car.

Figure 4 is a schematic electrical diagram showing perhaps the simplest implementation of the present invention, where the variable voltage is used to power the motor on the model vehicle and where the operating voltage is used simply to power, and to keep illuminated at a constant brightness, a model set of headlights in the form of a pair of light emitting diodes.

Figure 5 is a schematic block diagram of a more complicated model vehicle, according to the present invention, where the variable voltage is used to power the motor on the model vehicle and where the operating voltage is used to power a controller which responds to sensors and controls different aspects of the operation of the model vehicle.

Figure 6 is a plan view of a model vehicle track, according to the present invention, where various passive (and not so passive) items are readable to a model vehicle as it passes along the track, and

where one or more trackside utilities can be used to interact with the track to enhance the desirability and utility of the track.

Figure 7 is an electrical schematic diagram of a trackside utility, according to the present invention, showing how a controller can be powered by the operating voltage, the controller being operative to receive input from one or more sensors and operative to provide operating and controlling output to one or more items.

Figure 8 is an electrical schematic diagram of perhaps the simplest application of the present invention to a trackside utility, where an item can simply be switched on and off as use is desired.

Figure 9 is an isometric projected view of a portion of a model vehicle track, according to the present invention, where one or more electrical outlets are provided to power one or more trackside utilities.

Figure 10 is an electrical schematic diagram showing how the power supply circuit of Figure 3 can be improved to provide selectable pulse width modulation and/or frequency modulation to the high frequency waveform, and how, additionally, command and control signals can be coupled to and from trackside utilities and model vehicles, Figure 10 also illustrates how the command and control signals may be provided at and received from a computer or other processor or controller.

Figure 11 is a schematic electrical diagram showing how the trackside utility of Figure 7 can have a communications device affixed thereto to benefit from command and control signals.

Figure 12 is a schematic electrical diagram showing how a model vehicle of can have a communications device affixed thereto to benefit from command and control signals, and how a model track vehicle can be used with an AC variable voltage, or with a

capability to go both ways round a track when the variable voltage is AC.

Figure 13A is a cross sectional plan view of a simple acceleration and deceleration sensor which can be used in a model vehicle employing a controller.

Figure 13B is a plan view of a board bearing two orthogonal sensors as shown in Figure 13A which permit a model vehicle to sense acceleration, deceleration, left turns and right turns.

Figure 14 shows an embodiment of Figure 10, where the output of the high frequency inverter is balanced between the first conductor and the second conductor so to minimise electromagnetic interference.

Figure 15 shows an embodiment of the present invention where the supply to the first and second rails is, in this instance, a fixed AC or DC voltage and where commands are used to regulate the speed of the model vehicle.

And Figure 16 is a chart showing the waveform and structure of one possible. form of command to be communicated to a model vehicle.

Attention is first drawn to Figure 1A which shows an element of prior art model car racing tracks in the form of a DC power supply 10 where a transformer 12 powered from an AC supply main 14 generates a low AC voltage in a secondary winding 16 which is rectified by bridge rectifier 18 and can be smoothed by smoothing capacitor 20 to provide a fixed low voltage output. The low voltage output is sufficient to cause a model car on a track to operate at its maximum speed.

Other systems exist, in particular where the power supply 10 can be a simple AC transformer, a model racing vehicle being propelled by

AC power. While the following description is directed towards a DC power supply 10, it is to be appreciated that the present invention also encompasses such an AC power supply embodiment, as will be made clear in the description relating to Figure 12.

Attention is next drawn to Figure 1B showing the internal components of a model racing car according to the prior art.

A brush assembly 22 comprises conductors 24 which are insulated from one another by an insulator 26, the conductors 24 moving with the model vehicle in a slot on the model vehicle track and picking up power from the track to be applied to the model vehicle. A suppression capacitor 28 suppresses noise and arcing, a DC motor 30 causes the model racing car to move and light emitting diodes 32 are powered via current limiting resistors 34 to give the impression of headlights, or other lights, upon the model vehicle.

Attention is next drawn to Figure 1C showing one prior art embodiment of the overall model vehicle track. The power supply 10 is coupled through user adjustable rheostat 36 to a first conductor 38 on the side of a slot 40 in the model vehicle track 38,44 and directly to a second conductor 42 on the other side of each slot 40 in the model vehicle track 44. Each model vehicle has its brush assembly, 22 in and guided by the slot 40. The speed of the model vehicle is determined by the setting of the user adjustable rheostat 36.

A disadvantage of the arrangement shown is that the light emitting diodes 32 emit no light until the voltage, applied to the vehicle track 38,42 exceeds the pre-determined voltage, namely the offset voltage of each light emitting diode 32. Further, the brightness of the light emitting diodes 32 varies with the speed of the model vehicle. As will become clear from the following description, the present invention overcomes this problem.

Attention is next drawn to Figure 1D showing an improved prior art version of the circuit shown in Figure 1C where an extra contact 43 is provided at the high resistance end of each user adjustable rheostat 36 whereby the vehicle tracks 38,42 can be shorted out to cause the DC motor 30 to act as a dynamo and to provide regenerative braking for a model car.

The user adjustable rheostats 36 are normally provided each as a handheld unit, connected by a flexible wire to the power supply, and comprising a handle or grip together with a spring returned trigger, to be operated by one or more fingers, the whole permitting the user to control the speed of his individual model vehicle.

Attention is next drawn to Figure 2A showing a model racing car track 44 according to the prior art. The model racing car track 44 comprises a planar surface 46 whereon a pair of model racing cars can run. First conductors 38 are provided on a first side of the vehicle guidance slot 40 and second conductors 42 are provided on a second side of the vehicle guidance slot 40. The model racing car track 44 is provided in straight and curved sections which can be plugged together to make a complete track. At a first end 48 of each section the first conductors 38 comprise first conductor protrusions 50 which plug in to the first conductor 38 on the next adjacent, section of the model racing car track 44. At the second end 52 of each section of model racing car track 44 the second conductor 42 comprises second conductor protrusions 54 which plug into the second conductor 42 in the next adjacent section on model racing car track 44. In this way different sections of model racing car track 44 can be assembled with a continuous first conductor 38 and a continuous second conductor 42. The power supply and other items, shown in Figures 1A to 1D, are connected via any single point on the continuous conductors 38 42.

Attention is next drawn to Figure 2B showing a model racing car 56 according to the prior art. The model racing car 56 houses DC motor 30, the suppression capacitor 28 and (electrical connections not

shown) the light emitting diodes 32 together with the current limiting resistors 34. The brush assembly 22 is housed in the slot 40 and can be coupled via a coupling 58 to act upon the wheels 60 to cause the model racing car 56 to steer itself around the model racing car track 44. The wheels 60 rest upon the planar surface 46.

The DC motor 30 is coupled, either directly or through a gearbox, to drive the wheels 60 of the model racing car 56.

Attention is next drawn to Figure 3 showing a first embodiment of a power supply for a model racing car track 44. In Figure 3, many items that found in Figure 1D are duplicated, and like numbers represent like items. Several different features however, not shown in Figure 1D, are provided.

A high frequency inverter 62 is powered from the DC power supply 10.

An isolated output 64 of the high frequency inverter 62 is coupled to be connected to the second conductors 42 in the model racing car track 44. The isolated output 64 of the high frequency inverter 62 is also provided through coupling capacitors 66 to each of the first conductors 38 in the model racing car track 44, the coupling capacitors 66 blocking the DC component of any signal on the first conductors 38 so that the isolated output 64 (in this instance in the form of a winding on a high frequency transformer) does not short-circuit the DC voltage supplied to the first conductors 38 via their individual user adjustable rheostat 36.

A first inductor 68 is provided between the DC power supply 10 and the user adjustable rheostats 36 to prevent the smoothing capacitor 20 of the DC power supply 10 causing an apparent dead short to the high frequency signal from the high frequency inverter 62 when the wipers of either of the user adjustable rheostats 36 are in their minimum resistance position. A second inductor 70 is provided between the highest resistance setting end of the user adjustable rheostat 36 so that an apparent dead short to the high frequency signal from the high frequency inverter 62 is avoided when the

wipers of either of the individual user adjustable rheostat 36 is touching the contact 43.

In this way, a fixed voltage high frequency signal is provided on the conductors 38,42 of the model racing car track 44 together with a variable DC voltage, used to provide motive power for the model racing cars 56.

Attention is next drawn to Figure 4, showing the elements of possibly the simplest embodiment of a model racing car which can be made according to the present invention.

The brush assembly 22, the suppression capacitor 28 and the DC motor 30 are all as earlier described. One or more isolating inductors 72 are positioned between the brush assembly 22 and the combination of the suppression capacitor 28 and from providing an apparent full or partial short to the high frequency signal from the high frequency inverter 62.

The output of the brush assembly 22 is coupled through a first rectifier capacitor 74 and is connected back to the brush assembly 22 by means of a first rectifier diode 76. The junction between the first rectifier capacitor 74 and the first rectifier diode 76 is coupled through a second rectifier diode 78 to a second rectifier capacitor 80 which also is connected back to the brush assembly 22.

The polarities of the first rectifier diode 76 and the second rectifier diode 78 are such that the combination of the first and second rectifier capacitors 74,80 and the first and second rectifier diodes 76,78 form the well known"voltage doubling rectifier"circuit. The second rectifier capacitor 80 provides a DC voltage, derived from the high frequency output of the high frequency inverter 62, able to run equipment in the model racing car 56. The amplitude of the output, coupled to the first 38 and second 42 conductors, is deliberately kept low, in this example, at around 1.5 volts RMS amplitude. This is to reduce electromagnetic interference from the high frequency signal. Rectifier diodes are,

for preference, Schottky devices for improved efficiency at low voltages. The high frequency signal is voltage multiplied to provide a DC rectified voltage, the operating power, suitable for whatever purpose to which it is to be applied. The voltage doubler circuit, 74,76, 78,80 of Figure 4 can equally be a straightforward rectifier circuit comprising a smoothing capacitor if a very low voltage is required, or can be any of the numerous and well known voltage multiplication rectifier circuits which will be familiar to any individual schooled in the art. More than one rectifier or voltage multiplying rectifier can be coupled to the brush assembly 22 to provide operating power for a plurality of devices which require different voltages for operation.

In the example given in Figure 4, the operational power, derived from the voltage multiplied and rectified signal derived from the high frequency inverter 62 is used to drive the light emitting diodes 32 through their current limiting resistors 34, as previously seen with reference to Figure 1B. However, a considerable advantage is gained over the embodiment shown in Figure 1B because the output from the light emitting diodes 32 is now independent of how much DC voltage is being applied to turn the DC motor 30. Further, close examination of the circuit of Figure 1B shows that the light emitting diodes 32 are polarity sensitive. If the model racing car 56 is placed other than a preferred way round on the model racing car track 44, the light emitting diodes 32 simply will not light.

By contrast, because they are fed from rectification of an AC signal, the light emitting diodes 32 of Figure 4 have constant illumination no matter which way round the model racing car 56 may be placed on the model racing car track 44.

The light emitting diodes 34 are here given merely by way of a simple example of items which can now enjoy direction independent constant drive ability as a first consequence of the application of the present invention. The light emitting diodes 32 can be replaced by, or joined by, any other items, such as noise producing devices,

small motors and electromechanical actuators to operate parts of the model racing car 56 and tail lights, to name but a few.

Attention is next drawn to Figure 5, showing an improved content, over that shown in Figure 4, for a model racing car 56 constructed according to a further aspect of the present invention.

Many elements of the circuit shown in Figure 5 are common to those shown in Figure 4, and like numbers indicate like items.

Instead of (or, perhaps, as well as) powering the light emitting diodes 32 shown in Figure 4, the DC voltage provided at the second rectifier capacitor 80 is used to power a controlling microprocessor 82 which can be used for sophisticated and versatile control of many aspects of the model racing car 56.

A low voltage sensor 84 senses the voltage across the second rectifier capacitor 80 and provides a reset input 86 to the microprocessor 82 whenever the voltage across the second rectifier capacitor 80 re-establishes itself for proper operation. In this way, whenever the circuit of Figure 5 is powered down because of the model racing car 56 coming off of the model racing car track 44, or for any other reason of power loss such as intermittent contact, the microprocessor 82 is reset so that it does not go into an uncontrolled set of operations.

The controlling microprocessor 82 is operative to receive sensor inputs 88 which can detect various aspects of the operation and the position on the model racing car track 44 of the model racing car 56. For example, an optical sensor coupled to one or more of the wheels of the model racing car 56 can provide an input indicative of the speed or acceleration of the model racing car 56. Another input might sense optical signals which can be read as the model racing car 56 moves around the model racing car track 44. Yet another sensor input 88 can be coupled to a magnetic detector to detect when the model racing car 56 passes a magnet on the model racing car

track 44. These, and other sensor inputs 88, are discussed hereafter, with reference to Figure 6.

The microprocessor 82 also provides outputs. A first output can drive an acoustic transducer or loudspeaker 90 which can be used to generate model racing car 56 engine noises and braking noises in response to the acceleration or deceleration of the model racing car 56. Once again, these aspects are discussed later in the description. Other outputs can include, but are not limited to, a brake light activating output 92 and a headlight control output 94.

Those, skilled in the art, will be limited as to the number and nature of outputs 92,94 only by their imagination, and the availability of output signals.

Attention is next drawn to Figure 6, showing a plan view of a section of model racing car track 44 showing how the present invention enables the use of various trackside utilities.

The trackside utilities can comprise an active trackside utility such as, in this example, a traffic light 96 which can contain a microprocessor 82 similar to that shown in Figure 5, which can be powered from the first 38 and second 42 conductors of the model racing car track 44, and which can comprise sensors 98 for providing input to the microprocessor 82, in this example the sensors 98 being a light source and a photodetector for detecting passage past the traffic light 96 of a model racing car 56. The present invention, by enabling operational power to be present on the model racing car track 44 at all times, regardless of the velocity of the model racing car 56, means that trackside utilities of all kinds, from simple non-responsive items to those controlled by a sophisticated microprocessor 82 that controls the trackside utilities, can now be used. An active trackside utility can also comprise a changeover section whereby a vehicle can choose an alternative lane, either just for choice or to overtake a slower vehicle, or to enter or leave a pit lane.

There can also be passive trackside utilities. A first example is given by magnets 100, set into the planar surface 46 of the model racing car track 44, and detectable, as earlier described with reference to the sensor inputs 88 of Figure 5, by a magnetic sensor in the base of a model racing car 56.

Another passive trackside utility can be a simple strip of adhesive label with, in this example, black and white transfer stripes for the label to act as a speed measuring device 102. A passing model racing car 56 can read the speed measuring device 102 by means of a reflective photodetector on the base of the model racing car 56.

Another possibility is for bar codes 104 to be read by the model racing car 56 which can be used to define the behaviour of the model racing car 56 when the model racing car 56 is passing over that section of the model racing car track 44, thereby defining model racing car 56 behaviour when on that section of model racing car track 44.

The examples of passive trackside utilities are merely for illustration, and do not consist in a limiting set. The number and nature of different trackside utilities that are provided by the present invention is limited only by the imagination of the designer and the number of different interrogation facilities provided on a model racing car 56.

Another type of trackside utility is a selectably operable trackside utility, i. e. capable of being switched on or off, and given, by way of illustration, in the form of an LED light source 106 which can be detected by a photodetector on the model racing car 56. The LED light source 106 can be powered from the first conductors 38 and second conductors 42 in the model racing car track 44, in this example the power being derived from the conductors 38,42 in adjacent model racing car 56 paths, and can be switched on or off as required. The LED light source, for example, can be pulsed or modulated either to control the actions of the model racing car 56 or to provide a means whereby the output of the LED light source 106

can be distinguished from background radiation. Detection of the LED light source 106 can be used to control any suitable aspect of the behaviour of the model racing car 56.

The example given for a selectably operable trackside utility is merely for illustration, and does not consist in a limiting set. The number and nature of different selectably operable trackside utilities that are provided by the present invention is limited only by the imagination of the designer and the number of different interrogation facilities provided on a model racing car 56.

The examples given in Figure 6 are merely a small subset of the possible trackside utilities which can now be powered, controlled and responded to by means of the present invention.

Attention is next drawn to Figure 7 showing a schematic diagram of exemplary on-board electronics for the trackside utilities such as the traffic light 96 of Figure 6.

Many of the items in Figure 7 correspond to items also shown in Figure 5, a schematic block diagram of the electronics in an exemplary model racing car 56. Like numbers refer to like items and like descriptions also apply. Outputs 93 (here replacing the outputs 92 94 shown in Figure 5) can be used to switch on and off items appropriate to the particular trackside utility. As an example of further activity which can be undertaken by the controller 82, one of the outputs 93 can drive a transistor 108 to switch on and off a utility motor 110 which can be used to power, perhaps via a gearbox, mechanical aspects of a trackside utility.

One example could be that the trackside utility is a level crossing (for example on a railway track) and that the utility motor 110 could be used to raise or lower the level crossing gates. The loudspeaker 90 could then, at appropriate times, make noise appropriate to warning bells, klaxons etc while one of the other outputs 93 can be used to generate output from warning lights.

The use of a controller in a trackside utility thus permits, in combination with the present invention which provides a constant power supply, the provision of trackside utilities previously impossible under the prior art.

Attention is next drawn to Figure 8 showing a schematic diagram of the very simplest form of trackside utility, the selectably operable trackside utility. Once again, operational power is derived from the conductors 38,42 through a voltage doubling rectifier circuit 74,76, 78,80 to power any trackside item 112 which can be switched on or off via a trackside item switch 114. The trackside item 112 can be anything at all that might perform a useful or entertaining function on the model racing car track 44. Another example could be to have moveable points that could cause a model racing car 56 to change from one path to another either at periodical intervals or permanently on the throw of the trackside item switch 114, such another path being, for example, a parallel'pit lane'.

Attention is next drawn to Figure 9 showing an oblique isometric view of a cutaway portion of the model racing car track 44 and, among other things, provides further clarification of the nature of the first conductor 38, the second conductor 42 and of the slot 40.

Figure 9 also illustrates how power outlets 116 can be set into the planar surface 46 and the side walls 118 of the model racing car track 44 to provide a potential supply from the first conductor 38 and from the second conductor 42 to trackside items.

Attention is next drawn to Figure 10 showing a further improvement on the power supply arrangement over that already shown in Figure 3.

Many items are the same as indicated in Figure 3 and like numbers denote like items. The high frequency inverter 62 is modified over that shown in Figure 3 to provide a mark to space ratio adjustment 120 and/or a frequency adjustment 122 whereby the high frequency signal from the high frequency inverter 64 can be used, by trackside utilities and/or by model racing cars 56 to indicate a variable or

proportional value. Amplitude modulation can also be used. One or other of the mark to space ratio adjustments 120 and the frequency adjustment 122 can be used to moderate the pitch of the engine noises provided through the loudspeaker 90, to moderate braking distances and so on. One of the mark to space ratio adjustments 120 or the frequency adjustment 122 can be used to moderate one model racing car 56 and the other can be used to moderate the other model racing car 56 of a pair. The variable adjustments 120 122 can be incorporated into the hand held assembly used for each user adjustable rheostat 36.

Another difference over the arrangements shown in Figure 3 is provided by a modem 124 operative to pass messages to and from a computer 126 or other processor.

The modem 124 is coupled to provide signals to and receive signals from the first conductor 38 for each model racing car 56. The controlling microprocessors 82 on each model racing car 56 is, as hereinafter made clear, able to provide reports to and to receive instructions from the computer 126 via the modem 124.

Attention is next drawn to Figure 11 showing another embodiment of the electronics within a trackside utility such as the traffic light 96 when the arrangement of Figure 10 is used.

Everything in Figure 11 is as it is in Figure 7, there being many elements in common. Like numbers designate like items.

The main difference between Figure 11 and Figure 7 is that a trackside utility modem 128 is coupled to the first conductor 38 of the model racing car track 44 and provides the modulated instructional messages to and receives report messages from the controlling microprocessor 82. The instructional messages can include data and program elements to tell each output 93 when to function. Report messages can be sent concerning the current

activities of the processor 82 and reporting the state of the individual sensor inputs 88.

Attention is next drawn to Figure 12 showing a schematic diagram of the electronic content of a model racing car 56 when used on a track 44 taking advantage of the utilities discussed and shown with reference to Figure 10.

Many of the items shown in Figure 12 are common to Figure 5, and like numbers designate like items.

A difference between Figure 12 and Figure 5 is to be found in the model vehicle modem 130 which is coupled to that conductor on the brush assembly 22 which contacts the first conductor 38. The model vehicle modem 130 encodes and decodes messages, the decoded messages being instructional messages from the computer 126 and the encoded messages being reports from the microprocessor 82 concerning activities, inputs from the sensor inputs 88 and the condition and state of outputs 93. The instructional messages from the computer 126 can include routines with different times and different behaviours to be followed by the controlling microprocessor 82. One of the sensor inputs 88 can be coupled to the line from the brush assembly 22 that contacts the first electrode 38 and another of the sensor inputs 88 can be coupled to the line that comes from the brush assembly 22 that contacts the second conductor 42 thus to enable the microprocessor 82 to monitor the mark to space ratio and the frequency of the high frequency wave form from the high frequency inverter 82, which can also be an amplitude modulated signal, no matter which way round the model racing car 56 is facing on the model racing car track, as a frequency discrimination and/or amplitude comparator circuits can be used. Likewise, the model vehicle modem 130 can be coupled with two inputs, one ultimately originating with the first conductor 38 and the other ultimately originating with the second conductor 42 whereby one or other of the connections will function to transfer data no matter which way round

the model racing car 56 is sitting on the model racing car track 44.

The double connection of the model vehicle modem 130 can be implemented in the circuits shown in Figure 11 so that the controller 82 for a trackside utility can be plugged in the wrong way round, if required. Likewise, one of the sensor inputs 88 can be connected to the first conductor 38 and another sensor input 88 can be connected to the second conductor 42 permitting the microprocessor 82 of Figure 11 to monitor the mark to space ratio and the frequency of the high frequency signal provided by the high frequency inverter 62. Thus, not only the model racing car 56 whose contents are shown in Figure 12, but also the trackside utility of Figure 11, can function no matter which way round it is connected to the conductors 38,42. The rectifiers 74,76, 78,80 ensure that a power supply of correct polarity is always available to run the trackside utility. Likewise, with reference to Figure 12, the model racing car 56 can function on the model racing car track 44, no matter which way round the model racing car 56 is facing. Assured forward motion of the model racing car 56 can be provided by means of a DC motor bridge rectifier 132 which assures movement of the model racing car 56 in the direction appropriate to the shape of the body. The bridge rectifier 132 also permits use of the model racing car where the variable voltage from the rheostats 36 and the power supply is of an AC nature.

The high frequency signal, providing operating power, is higher in frequency than the output of the power supply 10, even when the power supply is not DC but AC, thus enabling frequency selective (bandpass, low pass or high pass) filters being used to separate one from the other. Likewise, the modem 124 128 130 messages are at a different frequency than either of the outputs of the power supply 10 or the high frequency inverter 62, thus enabling further frequency selective (bandpass, low pass or high pass) filters being used to separate the modem 124 128 130 signals from the other two components.

The microprocessor 82 outputs 93, in this example, also control a relay 160, which can be implemented as a solid state device such as a silicon switcher transistor, or a MOSFET transistor, with on/off contacts in series with the DC motor 30, thereby to control supply of motive power to the model racing car 56. This feature, by way of non limiting example, can be used to provide full motive power, no motive power, or by intermittent or proportional switching, reduced motive power, to simulate various conditions of"health" (such as reduced power after a collision) or"penalty" (such as a period of being stopped or at reduced power which may be incurred by, for example, passing the traffic light 96 at red or failing to go in for a'pit stop') to be experienced by the model racing car 56.

Attention is drawn to Figure 13A which shows a device, for use with the controlling processor 82 in a model racing car 56 to provide input to the sensor inputs 86 relating to the acceleration or deceleration of the model racing car 56.

A directional excess rate of change of speed sensor 134 comprises an insulating tube 136 made, for example, from plastic, wherein a ferromagnetic ball bearing 138 is free to roll up and down. A magnet 140, spaced from the insulating tube 136, attracts the ferromagnetic ball bearing 138 to stay at the centre portion of the insulating tube 136. A first end 142 is covered by a first electrically conductive cap 144 which preferably seals the first end 142 of the insulating tube 136 and prevents the ferromagnetic ball bearing 138 exiting from the insulating tube 136 at the first end 142.

A second end 146 of the insulating tube 138 is covered and sealed by a second electrically conductive cap 148 which prevents the ferromagnetic ball bearing 138 from being lost from the second end 146 of the insulating tube 136.

A first ball bearing sense electrode 150 is provided at the first end 142 of the insulating tube 136, and on the inside surface of the

insulating tube 136. If the ferromagnetic ball bearing 138 experiences enough acceleration or deceleration force for the ferromagnetic ball bearing 138 to move to touch the inside of the first electrically conductive cap 144, the ferromagnetic ball bearing also touches the first ball bearing presence electrode 150 to short together first conductors 152.

The second end 146 of the insulating tube 136 comprises a second ball bearing presence electrode 154 on the inner surface of the insulating tube 136. If the force due to acceleration or deceleration causes the ferromagnetic ball bearing 138 to reach the second electrically conductive cap 148, the ferromagnetic ball bearing also contacts the second ball bearing presence electrode to short out second conductors 156. The first conductors 150 and the second conductors 156 are external to the insulating tube 136.

Thus, if the ferromagnetic ball bearing 138 shorts out the first conductors, it is indicative of the excess rate of change of speed sensor accelerating in the direction of the second end 146 or decelerating in the direction of the first end 142. If the ferromagnetic ball bearing 138 shorts out the second conductors 156 it is indicative of more than a predetermined rate of acceleration being applied in the direction of the first end, or in excess of a predetermined rate of deceleration occurring in the direction of the second end 146. The predetermined amount of acceleration or deceleration is set by the strength of the magnet 140 and its distance from the ferromagnetic ball bearing 138 when it is in the centre portion of the insulating tube 136.

Attention is next drawn to Figure 13B showing how a first excess rate of change of speed sensor 134A can be mounted on a first axis on a board 158 and a second excess rate of change of speed sensor 134B can be mounted on a second axis, at right angles to the axis of the first excess rate of change of speed sensor 134A. The first electrodes 152A and 152B and the second electrodes 156A and 156B are coupled to the sensor inputs 88 on the controlling microprocessor 82 in a model racing car 56. The board 158 is laid with its plane

parallel to the base of the model racing car 56 and, for the sake of explanation of this example, the upper part of Figure 13B facing towards the front of the model racing car 56. Thus, if the first conductors 152A are shorted it indicates that the model racing car 56 is decelerating, so that the controlling microprocessor 82 can be caused to show brake lights and to make suitable deceleration noises. If the first second conductors 156 are shorted together, it is indicative of the model racing car 56 showing fierce acceleration. The controlling microprocessor 82 can thus be caused to make strenuous engine noises.

If the second first electrodes 152B are shorted together, it is indicative of the model racing car 56 going round a corner to the left. The controlling microprocessor 82 can thus be caused to activate left indicator lights (if so desired) and to make appropriate tyre squealing sounds indicative of the model racing car 56 going around a corner to the left.

If the second electrodes 156B are shorted together, it is indicative of the model racing car 56 going round a corner towards the right.

The controlling microprocessor 82 can thus be caused to activate right turn indicators (if so desired) and to generate squealing noises appropriate to the model racing car 56 going round a right hand corner.

The present invention also permits the controlling microprocessor 82 to apply limits to the performance of the model racing car 56 either on command from the computer 126 or as a result of the model racing car 56 having sensed collisions or other incidents which could be expected to disable a car in real life. Such sensing of collisions are done with further excess rate of change of speed sensors 134, this time with a much stronger magnet 140 which will only allow the ferromagnetic ball bearing 138 to short out electrodes under conditions of extreme acceleration or deceleration. The condition of being"crippled"of a model racing car 56 can be indicated by the controlling microprocessor 82 by generating"crippled engine and

body"noises and by regulating the available power to the DC motor 30 by means of, for example, a relay 160 or semiconductor device in series with the DC motor 30 which only allows power to be applied thereto for a controllable proportion of the time.

The present invention thereby allows realistic behaviour to be provided in a model racing car 56 under conditions of collision and damage.

Attention is next drawn to Figure 14, showing an embodiment of Figure 10, where the output of the high frequency inverter 62 is balanced between the first conductor 38 and the second conductor 42 by means of a first balancing choke 162 connecting the second conductor of a first track 44A to the ground terminal of the DC power supply 10 and a second balancing choke 164 connecting the second conductor 42 of a second track 44B also to the ground terminal of the DC power supply 10. The output signal of the high frequency inverter 62 is thus balanced between each of the first 38 and second 42 tracks so to minimise electromagnetic interference.

Figure 14 further illustrates how a band pass filter 166 can be used within the modem 124 to select only the appropriate frequency signals for decoding. The modem 124 comprises individual grounds and inputs for receiving signals from the first track 44A and the second track 44B.

The computer 126, or the controlling microprocessor 82, or both together, is also usable not only to monitor what occurs on the track 44, but also to command and control individual vehicles 56. A non-limiting example of such control would be to cut or reduce power to a vehicle, for a predetermined period, as a penalty for shooting a traffic light 96, exceeding the speed limit, failing to make a pit stop, and so on. More than one controlling microprocessor 82 can be provided and be in communication with a computer 126 to allow 2, 4,6 or more tracks simultaneously to be used.

Attention is next drawn to Figure 15 showing an embodiment of the present invention for use where the voltage supply to the first conductor 38 and the second conductor 42 is a fixed DC or AC supply.

Objects in Figure 15 are similar to objects found in Figure 12, and like numbers refer to like items.

Because the supply to the first 38 and second 42 conductors is now a fixed quantity, capable of powering the controlling microprocessor 82, there is no longer need to rectify the output of the high frequency inverter 62 to power the controlling microprocessor 82.

In the example given in Figure 15 the microprocessor 82 is controlled directly from the first 38 and second 42 conductors and the first rectifier capacitor 74, the first rectifier diode 76, the second rectified diode 78 and the second rectifier capacitor 80 are all omitted.

The supply, in the example given for Figure 15, is a fixed value DC supply. The DC motor bridge rectifier 132, otherwise shown in Figure 12, is not shown in Figure 15. If, however, the supply between the first conductor 38 and the second conductor 42 had been an AC supply, the bridge rectifier 132 would have been included to provide a DC output.

The model vehicle modem 130 receives commands and reports conditions as before, the difference being that the model vehicle modem 130 now receives commands for regulating the speed and/or the direction of the model vehicle.

A first difference is that the relay 160 now, instead of opening and closing a single switch, is used to operate a double pole double throw switch which can cause the DC motor 30 to run in a selectable direction from the DC supply.

A second difference is the provision of a DC regulator 168 between the power take off from the first 38 and second 42 conductors and

the relay 160 contacts. The model vehicle modem 130 receives an instruction for the control of the speed and direction of the DC motor 30. The controlling microprocessor 82 receives and interprets the instruction, and then sets the switch direction of the relay 160 to the appropriate direction and provides a voltage controlling command to the DC regulator 168 via an output 93. The output 93 can be of any form capable of providing a delivery command to a DC regulator. The output 93 can be mark space ratio modulated to produce a mean voltage which is the level to be obeyed.

Alternatively, the output 93 can be used to drive a digital to analogue converter which will also produce a controlled DC output for use by the DC regulator 168.

The system shown in Figure 15 is of particular use with model railway engines, where it now becomes possible selectably to move two or more engines, with independent speed and direction, on the same track. This allows, for example, a complete shunting yard to be operated down just two conductors 38 and 42.

Attention is finally drawn to Figure 16 which shows the signal which can originate from the modem 124 (shown in Figure 10) to send commands to a model track vehicle such as the model racing car 56 or a model train and so on. The command is provided in a series of binary digits which could, for the sake of example, provide an asynchronous signalling system such as is known in the RS232 definition. A preamble section 170 signifies the start of a message and synchronises the decoding of the following sections. A model vehicle addressing section 172 then indicates for which one of a plurality of model vehicles the command is intended. Only the particular addressed model vehicle will respond to a command.

Next a function addressing section 174 indicates for which aspect of the model vehicle's behaviour the instruction is intended. Aspects can range from the speed of the vehicle, the direction of the vehicle, lights and sound effects. Finally, an intensity indicating section 176 indicates the intensity of the stimulus to be applied.

For example, if the intensity indicating section 176 is directed towards the vehicle velocity, and is eight binary digits long, a reading of 256 will indicate maximum speed and a reading of zero will indicate zero speed. Other quantities may be switched on or switched off by simply having a reading of more than half. Where 256 is the maximum reading, for example, a reading in excess of 128 can switch a light on and a reading of less than 128 can switch a light off. Alternatively, the intensity of the light can also be proportionately controlled.

The example of a command signal given in Figure 16 is purely to indicate one of many different ways in which commands can be given to individual model vehicles.

Another example of the use of the present invention is on model 'bumper cars'or'dodgems'where the overhead electrified roof forms the equivalent of a first conductor 38 and the under-wheel conductive floor forms the equivalent of the second conductor 42, the speed and direction of each vehicle being controlled by the modulation (frequency, phase, mark to space ratio or amplitude) provided by the different adjusters 120 122 and any other that may be required.

The approach, described in the above paragraph, can also be applied to real-life, full size'dodgems'or'bumper cars'where a fairground operator can control individual real-life vehicles should control be lost by a customer or a customer exhibits unacceptable behaviour.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. Descriptions and disclosures herein are not intended to be in any sense limiting.