GB2082329A - Analogue encoder for slot machine reels - Google Patents

Abstract

An analogue encoder system encodes the instantaneous angular position of one or more spinning reels 10 in a microprocessor controlled amusement game such as a fruit machine. The analogue encoder provides substantially instantaneous angular position data to the microprocessor by measuring voltage across an electrical resistance track 11 between two points 15, 16 on the reel's periphery. The voltage is converted to digital form by an analogue digital converter 20, and then supplied to the microprocessor as input data. <IMAGE>

Description

SPECIFICATION Analogue encoder for slot machine reels This invention relates to rotary potentiometers for encoding the instantaneous angular positions of spinning reels in amusement games including fruit machines. More particularly, the invention relates to devices for providing instantaneous position information in the form of digital data input to a microprocessor controlling an amusement game.

In a microprocessor controlled fruit machine, for example, the microprocessor may be required to stop each of a plurality of spinning reels at a preselected position. The positions could be determined by microprocessor calculations conforming with particular rules governing the course of play. When the reels are stopped at the preselected positions there will be a preselected array of fruit symbols displayed on a win line. The present invention, therefore, provides such a microprocessor with the current position of each spinning reel. The microprocessor utilizes the position information to issue "stop" instructions in order to stop each reel at its predesignated position.

An example of a fruit machine feature for which the present invention can sense position information for a microprocessor is found in Bally Mfg. Co.'s co-pending application entitled "Swap Feature for Fruit Machines," Application No.

8026094. The invention may also be used to solve other sensing and control problems in gaming machines or amusement games.

Fruit machines are presently known in which electrical means are utilized to sense the angular position of a reel after the reel has stopped spinning. British Patent No. 1,423,415, for example, issued to New Century Novelty Company, Pty. Ltd. discloses a fruit machine reel having a resistor with two contact points adjacent to each symbol on a fruit machine reel. The resistance value of the resistor encodes the particular symbol displayed. A pair of wipers connected to a voltage source then identifies the particular symbol displayed by measuring the resistance adjacent to that symbol. The identification is used to determine whether the combination of stopped reels is entitled to a payoff.

The art exemplified by the New Century Novelty Company patent is not used for real time microprocessor control.

Rotary potentiometers have been used to indicate continuously the angular position of a rotatable shaft. British Patent No. 1,297,111 issued to Jones, for example, discusses the use of a rotary potentiometer for indicating wind direction. The output of the rotary potentiometer, can be fed to a simple galvanometer which, in turn, can drive a pen on a moving strip chart.

Rotary potentiometers have not, however been previously used in amusement games as sensing elements for microprocessors.

According to the present invention there is provided a gaming device having one or more reels that spin and then stop under control of a microprocessor and its associated memory, and including apparatus for transmitting to the microprocessor the instantaneous position of each reel by generating and measuring a voltage uniquely dependent upon the simultaneous angular position of the reel with respect to a spatially fixed point and then transmitting the voltage to an analogue/digital converter which converts the voltage to a digital signal capable of being read and acted upon by the microprocessor and stored in the microprocessor memory.

From another aspect the invention provides a microprocessor controlled gaming machine having at least one reel rotatable about an axis and measurement means to measure the angular position of the reel, said means comprising: electrical resistance means on the reel providing angularly distributed electrical resistance extending substantially completely about the axis of the reel; a pair of contact means to make electrical contact with said resistance means at a point fixed in space whereby the resistance between the contact means is dependent on the angular position of the reel; and electrical means to generate a digital signal proportional to said resistance for input to the microprocessor while said reel is rotating.

In one embodiment of the present invention the periphery of a spinning reel will comprise a conductor containing resistance. The resistance between any two points on the reel's periphery is made proportional to the angle subtended at the centre of the reel by the two points. In this first embodiment a reference point on the reel is connected to a fixed potential source through a slip-ring. The second terminal, which acts as a fixed-current source, contacts the periphery of the reel at a point fixed in space. The voltage difference between the second terminal will thereby be proportional to the instantaneous angular displacement of the reel. The voltage difference may then be fed to an analogue/digital converter. The output of the analogue/digital coverter becomes the input to the controlling microprocessor.

In an alternative embodiment of the invention two terminals may make contact with the reel at points separated by a fixed angular separation, the contact points being fixed in space. In this second embodiment the amount of resistance per unit of angular displacement is not constant around the reel but varies in accordance with a preset formula. The amount of resistance between the two terminals, therefore, will be uniquely related to the angular position of the reel. If one of the pair of terminals is then connected to a fixed potential, and the second terminal is a fixed current source, the voltage at the second terminal will define uniquely the angular position of the reel. That voltage is then fed to an analogue/digital converter, as before.

It is not necessary to have continuous resistance around the periphery of the reel. In another construction of the embodiment, discrete resistors may be placed connecting different points along the periphery of the reel without changing the principles taught by the present invention. When discrete resistors are used, the invention no longer provides a continuous indication of reel position. The microprocessor must then sample the output of the analogue/digital converter to determine reel position at times when each discrete resistor passes a contact point.

The implementation of either embodiment is not limited to detection of positions of a single reel. Positions of several reels may be determined by use of multiple techniques. In a complete machine, for example, the microcomputer could monitor the angular positions of several reels simultaneously and then issue stop instructions to means controlling the rotation of each of the several reels according to a programme contained in the microprocessor.

Examples of the invention will now be described with reference to the accompanying drawings in which FIGURE 1 illustrates a reel with continuous resistive track and associated means in accordance with the principles of the present invention; FIGURE 2 illustrates a reel similar to that in Figure 1 but with a continuous resistive track in which the resistance per unit angular displacement varies; and FIGURE 3 illustrates a reel similar to that in Figure 1 but with a descriptive track in which discrete resistances are distributed about the reel.

In FIGURE 1 a reel of a gaming machine is illustrated generally at 10. The reel 10 may comprise one of the indicating reels of a fruit machine for example. The reel 10 has a resistive track 11 extending about the axis 12 of rotation of the reel, The track 11 is circular centred on the axis 12 and is continuous apart from a break 13.

Immediately adjacent one side of the break 1 3 the track 11 is electrically connected to a continuous circular conductive slip ring 14 having a low resistance. Typically the ring 14 may be of copper. Electrical contacts are made to both the track 11 and the slip ring 14 by means of brushes 1 5 and 16, respectively. The brushes 1 5 and 1 6 are fixed in space. As a result the point of contact between the brush 1 5 and the track 11 is dependent on the angular position of the reel 10.

However, because of the low resistance of the ring 14 direct electrical contact is effectively made between the brush 1 6 and an end 1 7 of the track 11 adjacent to the break 13. The track 11 has a constant resistance per unit angular displacement about the axis 12 so that the resistance between any two points along the track 11 is dependent on their angular separation. It can accordingly be seen that the resistance between the brushes 1 5 and 1 6 is dependent on the angular position of the reel 10.

A current source 1 8 drives current from the brush 16, via the slip ring 14, through the relevant length of track 11 from the end 1 7 to the point of contact with the brush 1 5, and thence to earth.

Thus, a voltage developed on a line 1 9 connected to the brush 1 6 is indicative of the angular position of the reel 10. This voltage on the line 1 9 is fed to an analogue/digital converter 20 which provides a digital output representing the angular position of the reel. The digital output is then fed to the other circuitry of the game machine, for example, a microprocessor and an associated memory that controls game operation.

In the alternative arrangement shown in FIGURE 2, the track 11 has a non-uniform resistance per unit angular displacement.

Typically, the resistance per unit angular displacement along the track 11 may increase from one side 22 of a datum point 21 progressively to a maximum on the other side 23 of the datum. In this arrangement, contact is made to the track 11 by two brushes 24 and 25 both of which are fixed in space but arranged to contact the track 11 at two points which are angularly spaced on the track 11 about the axis 12. It can be seen therefore that the resistance between the brushes 24 and 25 is again representative of the angular positon of the reel 10, the relationship between the resistance and the angular position being dependent on the manner in which the resistance per unit angular displacement of the track 11 varies.

A signal representing the resistance between the brushes 24 and 25 is generated in the same way as for the embodiment of FIGURE 1.

In FIGURE 3 instead of a continuous track 11, a series of discrete conductor pads 26 are distributed at equal angular spacings about the axis 12 of the reel 10. Adjacent pairs of pads 26 are interconnected by discrete resistors 27.

Otherwise, the arrangement of FIGURE 3 operates similarly to the arrangements of FIGURES 1 and 2 except that the output signal generated varies in discrete steps rather than varying continuously. If the resistors 27 are all of the same value, then a digital equivalent of the embodiment of FIGURE 1 is provided; if the resistors 27 are of different values, e.g., progressively increasing about the axis 12, then a digital equivalent of the FIGURE 2 embodiment is provided.

Claims (7)

1. A gaming device having one or more reels that spin and then stop under control of a microprocessor and its associated memory, and including apparatus for transmitting to the microprocessor the instantaneous position of each reel by generating and measuring a voltage uniquely dependent upon the instantaneous angular position of the reel with respect to a spatially fixed point and then transmitting the voltage to an analogue/digital converter which converts the voltage into a digital signal capable of being read and acted upon by the microprocessor and stored in the microprocessor memory.

2. A microprocessor controlled gaming machine having at least one reel rotatable about an axis and measurement means to measure the angular position of the reel, said means comprising: electrical resistance means on the reel providing angularly distributed electrical resistance extending substantially completely about the axis of the reel; a pair of contact means to make electrical contact with said resistance means while said reel is rotating, at least one of said contact means contacting said electrical resistance means at a point fixed in space whereby the resistance between the contact means is dependent on the angular position of the reel; and electrical means to generate a digital signal proportional to said resistance for input to the microprocessor while said reel is rotating.

3. A gaming machine as claimed in claim 2 wherein one of the said contact means makes contact at a point fixed in space and the other at a fixed reference point on the resistance means, the resistance of the resistance means between any two points thereof being proportional to the angular displacement between the two points.

4. A gaming machine as claimed in claim 2 wherein both said contact means are arranged to contact said resistance means at points fixed in space which are at a predetermined angular separation about said axis, the resistance of the resistance means per unit angular displacement varying in a predetermined manner.

5. A gaming machine as claimed in any of claims 2 to 4 wherein the resistance means is a continuous resistive track.

6. A gaming machine as claimed in any of claims 2 to 4 wherein the resistance means is a series of discrete resistors interconnecting angularly distributed contact regions of the reel.

7. A gaming machine substantially as hereinbefore described with reference to and as illustrated in any of the accompanying drawings.