GB2339393A

GB2339393A - Electronic games board

Info

Publication number: GB2339393A
Application number: GB9919551A
Authority: GB
Inventors: Yehouda Harpaz
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-29
Filing date: 1999-08-19
Publication date: 2000-01-26
Anticipated expiration: 2019-08-19
Also published as: GB2339393B; GB2334680A; GB9907163D0; GB9919551D0

Description

2339393 Games Grid Board This invention relates to board games in which a

move is done by indicating a point on the board, and the state of the game is expressed in the state of the points. These include traditional games like OTHELLO (registered trademark) and Go, but also large number of other potential games, puzzles and exercises. The invention presents an electronic board to play these games. In this document, the term 'game' includes single or multiplayer games, puzzles and exercises.

Games like OTHELLO and Go are played by each player, in his turn, adding a pebble to the board, on one of the points in a grid of lines drawn on the board, or in one of the squares on the board. These games have the advantages of being based on simple playing acts and being interesting intellectually. Their disadvantages are:

1) They require somewhat tricky movement when putting the stone on the board in the right place without disturbing other stones. 2) They tend to suffer from delays when a player is thinking on a move. 3) Some of the moves require additional 'housekeeping' operations, e.g. taking stones of the board in Go or changing them to stones in another colour in OTHELLO. 4) The players need to keep the rules and do the counting of stones themselves, which puts extra demand on the players. 5) The stones are separate objects, which are easily lost.

Disadvantages 3-5 can be solved by programming a computer to display the board and stones. The program would be simple enough that it can be put on a small and cheap CPU, and hence be built into a standalone playing board. In principle, the computer could also limit the time allocated to each player, thus solving disadvantage 2.

The problem of input (disadvantage 1), however, is not solved so well by current electronic systems. That is because input for existing electronic systems is normally done through buttons, or other devices, which are separated from the display. For games where there is a small repertoire of possible different inputs this is acceptable, but for board games like OTHELLO, there are many possible different inputs (the number of points in the grid). Inputting a point on buttons off the display requires the players to perform some mental operation to convert the point they think about to the right input. This is relatively slow and error-prone process. For slow-going games that is very annoying but may be acceptable, but it makes it impossible to play fast on these systems, and for most people this is a decisive factor. The aim of the grid board is to solve this problem, by making the display of the state of the game (the board) also the place where the input from the players is received.

A possible way of achieving this is to use a flat display panel covered by a touch screen. Segmented display was also suggested as possible solution. These solutions give a very powerful combination, but they are very expensive and associated with various technical problems. For example, a prototype of the current invention, which was implemented using a touch screen on top of an LCD screen required components that cost more than I 000f, and requires calibration approximately once a weak. The invention here is based on the observation that many games do not require a complex (and hence expensive) display or 2 input mechanisms. Instead, they can be played on a simple (and hence cheap) grid of points. Once such a grid is made, it opens the possibility of playing many different games on the same grid, by avoiding any constraints on the rules of the games in the hardware, and let a CPU with a flexible program manage the behaviour of the grid.

The conceptual structure of the hardware of the grid board is sketched in Figure 1.

According to the current invention (the games grid board), the user accessible part of the grid board is made of gridpoints I & 2 which are arranged in a grid on a flat surface 6. Each grid point is a clearly visible element I which can detect when it is pressed, and can be illuminated in at least two colours; by an illumination source 2 in or below the surface. The figure shows only 3 grid points for clarity, but the actual board has many more grid points (typically 36 - 1000). The figure also shows the illumination source 2 separately from the visible part of the grid point 1, which denotes the fact that pressing a grid point does not affect its illumination. All the grid points are connected to a games manager 3, which is a CPU + memory + software. When a grid point is pressed, the games manager 3 I'S notified (arrows from the visible part I to the games manager 3), and the games manager 3controls which sources of illumination are on (arrows fTom the games manager 3 to the sources of illumination 2). The games manager is programmed to manage various games. Managing a game means that the board displays the state of the game by putting on the appropriate sources of illumination 2. When a sensor I is pressed, the games manager computes the implication according the rules of the current game, and changes some of the sources of illumination 2 (possibly none) to reflect the new state of the game. The board may also change which sources of illumination are on when no point is pressed.

To allow the users to utilise all the functionality of the board, it will need a control area 4, which allows the players to change the current game, change the rules of the current game and change other parameters, like the length of time that each player has to perform his move. The control area 4 also displays the current score of the game. Typically, the control area will contain few control buttons and an alphanumeric display. The games manager receives information from the control area about which control buttons were pressed, and controls what is displayed in the alphanumeric display.

The basic functionality of the games manager comprises these actions: 1) When the users indicate through the control area 4 that they want to change the current game or any of the parameters of the current game, the game manager sets its own internal state to the new value, and indicates to the users the new value.

2) When one of the grid points is pressed and the current game and parameters make it illegal for the current player to press some of the points, the games manager checks if the pressed point is allowed according to the rules and parameters of the current game and the current state of the game (i.e. which points are illuminated). If the pressed point is not allowed, the games board may issue some indication that an illegal point was pressed, may indicate why it is not allowed by some message through the control area 4, and may indicate which points are allowed (e.g. by flashing them). Note that illuminated points, while typically are not allowed, may be allowed in some games (for examples, see Life], Life2, Clearlt and FiXt on pp.7-8)- 3 3 3) When a point is pressed and it is allowed according to the current rules, parameters and state of the game, the games manager computes the implications and then changes the illumination of some (possibly zero) points to reflect the new state of the game. Note that:

a) While typically the point that is pressed changes its illumination, this is not mandatory. For example, in the gameFindThem (p.8) the pressed point changes only if it is was illuminated in the right colour earlier, and in the game Clearlt (p.8) the pressed point never changes.

b) Other points except the pressed point may change as well., e.g. points that are caught in OTHELLO and Go. In other games, every move changes some other points, e.g. the games Clearlt and Fillit (p. 8).

4) If the rules of the current game require it, the games manager changes the illumination of some points even when none of the points is pressed, typically once each some time period (or 'generation'). For examples, see the games Ghost, Touch1t, Life] and Life2 on pp. 7-8.

5) After each change to the illumination of any grid point, the games manager computes the current score and displays it using the control area 4.

6) After each change to the illumination of any grid point, the games manager checks, using a game-specific routine, if the game is finished. If the game is finished, the games manager indicates it, typically by some message in the control area 4, and maybe other additional signals. In some cases, finishing the game may involve some changes to the illumination of the grid points. For example, when Visiput (p. 9) reaches a finished position, i.e. it is clear what unilluminated points belong to which colour, the games manager illuminates all the points with the colour they belong to.

The board will also need a way to signal whose turn it is, which would typically be done by two turn lights 5, which are in two separate colours, corresponding to two of the colours of the illumination in the grid points. The games manager controls these turn lights, and signal to the players whose turn it is by switching the corresponding tum light.

The kind of games that the board will be programmed to play include (but not restricted to): 1) Traditional games like Go and OTHELLO, with the addition that the time allocated to each move can be limited, and that the games manager can be set to 'salt' the game by doing random changes to the board. The board is particularly useful for OTHELLO, in which the old-style board requires the players to reverse the colour of 'stones' in each turn. With the games grid board, this is done by the games manager. 2) Other two-player games between two human players or between a human and the games manager. Because the games manager checks the legality of moves, performs all the changes and computes the score, these games can have rules that require complex legality checks, extensive changes and difficult score calculations but still be easy to play, which opens many new possibilities. Examples include the games Visiput (p. 9), where checking the legality of a move is difficult to humans, CountLines (p.9), where computing the score correctly would be difficult for humans, and FiXt (p.8), where each move involve large changes to the board. All these games, which apart from these problems are 4 simple and intellectually interesting, are effectively impossible to play without the games manager. 3) Puzzles and single-player games. For examples see the games T6uchIt and Symmetry on p. 8. 4) Fluid games, which means games where the patterns of illuminated points changes even when the player(s) don't press any point. For examples see the games Life] and Life2 onp.8. TouchIt and Ghost(p.8) can also be regarded as a fluid game. Currently, there is no realistic way to implement these kind of games. 5) Memory games. See for example the game FindThem on p.9.

The games manager can be programmed to help the players to find which points are legal moves, typically by transiently illuminating (flashing) these points with the colour of the player. This needs to happen in response to some input, for example a player pressing a point which is illegal move. This is specially useful for novice players, which with this feature set on can learn to play a game simply by trying to play it.

Because the behaviour of the board (i.e. which points are illuminated) is completely controlled by the games manager 3, what games can be played and what parameters can be changed is completely determined by the software of the games manager, which would normally be stored in some kind of ROM. Even with a modest size ROM of 332kb, it is possible to store large number of games, with many settable parameters (the 12 games listed below use 26kb, including the main loop and the general code to display and set parameters), and the size of the ROM can easily be made larger so it can accommodate many more games. The number of possible games that can be played with the same board can be made indefinitely large by making it possible to load new games into the board. This can be done by making the ROM replaceable, or by adding a device to load software from a removable medium like a floppy disk.

The large vaniability of games that can be played on the same individual board means that the same board would be entertaining and interesting to a large variety of people. Experience with a prototype suggests that at least some of the games appeal to any age range from 4 years old to adults.

The arrangement of the grid points would be in most cases square, but can also be of different shapes (e.g. rectangular, hexagonal, triangular or less regular). The overall shape of the board can also vary.

A specific embodiment of the invention'"411 now be described with reference to the accompanying drawings:

Figure I shows the conceptual structure of the board. Figure 2 shows a sketch of the electronic components of an example board. Figure 3 is a sketch of the way the board looks for players from above.

The inputs of grid points 1 are implemented by a custom-design membrane keyboard 7 on a PCB 6, which together comprise the top of a flat rectangular box. The membrane keyboard contains a grid of 9x9 translucent buttons 1, which are in a shape of small domes. Between the buttons the membrane is painted with lines 8 drawn on the imaginary lines connecting the centers of the buttons. The PCB 6 has holes below each button, with additional holes 9 for the turn lights. Both the PCB 6 and the membrane keyboard 7 has a hole for the alphanumeric display 11.

The illumination of the grid points is implemented by 9x9 pairs of LEDs 2 mounted on a PCB 12, which is itself mounted below the membrane keyboard such that each LEDs pair 2 is under the centre of one of the buttons 1. In each pair one LED is of one colour (e.g. green) and the other of another colour (e.g. red). Alternatively, each LEDs pair can be replaced by a bi-colour LED. The two turn lights 5 are implemented by two large LEDs, one in one of the colours of the pairs of LEDs 2, and one in the other colour, mounted on PCB 12 as the rest of the LEDs. The electronic circuitry to drive the LEDs 2 and the turn lights 5 is also on PCB, 12.

The membrane keyboard 7 also contains several control buttons 10, which allow the users to control the game (start, stop etc.) and to select which game is played and set parameters for the current game. An alphanumeric display I I is mounted in a hole in the membrane keyboard 7. The control buttons 10 and the display I I together comprise the control area 4 of Figure 1.

All the input from the membrane keyboard goes to the games manager 3, which is a small CPU (around 5MIPS) and a little ROM and RAM (around 32Kb and 6 Kb respectively). The games manager 3 is placed below the LEDs PCB 12. A custom design electronic circuitry (denoted by arrows from the membrane keyboard 7 to the games manager 3, and from the games manager 3 to the PCB 12 and to the display 11) allows the games manager 3 to switch on and off each individual LEDs, and to display the appropriate information in the alphanumeric display.

Figure 3 shows a sketch of the board from above in a middle of a game, with some grid points illuminated. Most of the grid points are not illuminated (circles with points). Some of the points are illuminated in one of two colours (indicated in the figure by two different shading). Because the buttons are translucent (rather than transparent), the LEDs 2 are not actually visible.

The embodiment of the grid points which is described above seems to be the most effective with current technology, but some parts can easily be changed if and when other technologies improve or new technologies become available, without affecting the overall design of the board. The detection of pressing a grid point may be done by any discrete input device, for example standard contact switch and capacitive switch. The illumination of the grid points can be done by other kind of sources, for example gas-discharge lamps and incandescent lamps.

In the embodiment which was described above the players press the grid points with their fingers. This is very convenient, which is one of the advantages of the board. However, it has a problem that the board cannot distinguish which player is pressing a point, so the players can press a point out of their turn. The possible solutions to this problem seem to be too cumbersome and in some cases too expensive, so they are not included in the preferred embodiment. However, some of the solutions may prove to be convenient and cheap enough 6 to be acceptable, and if the board is used for formal tournaments it may become an essential requirement.

A cheap and simple solution is to add two buttons on two sides of the board, one for each player, and the player will need to either hold down his own button while pressing a point or to first press his button and then press the point.

Another solution is to have two probes connected to the board, and the players use them to press the points. The contact between the probe and the board creates a short circuit which the board detects and hence can tell which probe, and hence which player, presses the point. An advantage of this solution is that it means that the sensor in each grid point can be a simple conducting element, instead of the membrane keyboard which is described above, which may make the board actually cheaper. Alternatively this method can be used to detect which player presses a point, in combination with another method to detect which point is pressed. For example, a membrane keyboard can be coated with a conducting layer, and the short circuit is caused when the probe touches this layer. In this case the membrane keyboard will detect which point is pressed, and the short circuit detects which player presses it.

Another variation of this solution is that the board emits some signal (electromagnetic or maybe ultrasound), and the probe detects this signal, and the probe that detects the signal more strongly is the one that actually presses. In this case the probe does not need to touch the board, so may be worn by the players, rather than held, which is more convenient. Another variation is that the probe interferes with or reflects the signal, and the board uses this response to detect which player presses the board. in this case, the probe does not need to be connected to the board. Alternatively, the probes themselves may emit different signals.

The solution above requires the players to hold or wear an object, which is uncomfortable. A possible solution is to mark the fingers of the players, by some material that adhere to the skin, and that the board can detect. Even more advanced technology may be able to recognise the fingers of the players directly.

The software:

The central loop of the software repeats these four steps:

1) Check if any of the control buttons was pressed. if any control button was pressed, perform the appropriate operation (change the game, set a parameter, stop the game, start the game).

2) Check if any of the grid points was pressed. If so, compute the implications according to the rules of the current game, perform all the changes to the board, and then switch the turn to the other player. The computations for the game Go are given below as an example. Switching the turn means switching the turn light of the current player off, setting the internal variable current-Player to the other player, switching the turn light of 7 the other player on and setting a variable, the turn end mark, to the current time plus the turn time.

3) Check the clock and compare it to various time marks. A time mark is a variable set to 3 some value, which is compared to the current time. The most important is the turn end mark, and if this is passed, switch the turn as in 2. Other time marks are for updates of the displays.

4) Check if there are game specific operations to perform. If a player plays one of the two-players games against the board, this check perform the board's move. In the fluid games Ghost, Life], life2 and Touch1t this is used to perform the generation change in the Life games, adding a point in Touch1t, and moving the Ghost in Ghost.

Operations of the software when a grid point is pressed and the current game is GO:

a. Switch of the turn light of the current player and set a short (Current time + -500 ms) delay mark. b. If checing for KO is switched on, check if the move breaks the KO rule. If it does, reject it, which means notify the players via the character display, switch on the turn light of the current player on and return to the main loop. c. Check if as the result of this move any of the points of the opponent's colour are captured, i.e. completely surrounded by points of the current player's colour. If so, switch these points off. d. Check if the pressed grid point is part of a group of points of the current player's colour which is completely surrounded by points of the opponent player's colour. If so, reject the move as in (b) above. e. Switch on the colour of the current player in the grid point. f Check if the game is decided, i.e. if it is clear which part of the board is controlled by which player. If it is, end the game, g. Update the digit display to show the new count of points for each player. h. Wait until the delay mark which was set 'in step (a) passes. i. Pass the turn to the other player, i.e. switch the turn light of the other player on and set the time mark (current time + the time for a move) for this player.

Games implemented in the prototype of the Grid Board The following 12 games have been implemented in the prototype of the board. Each game has several parameters that can be set, but only a minority of these are described here. Each two-players game can also be played against the board. With the default parameters settings, Othello, CountLines and Visiput flash the legal moves for a player that presses a point that is an illegal move.

1) Othello. 'Adding a stone' is done by pressing an unilluminated point. If this is a legal move, the games manager switches the point on with the current player's colour (which corresponds to putting a stone in this point) and reverses the colour of the points that need 8 to be reversed according to the rules of OTHELLO. Because the number of points is 9x9 rather than the usual W, the start up position is different from the standard starting position. In each move the games manager checks if the current player -has a legal move, and if not passes the turn to the other player. If both players don't have a legal move, the games manager finishes the game. In OTHELLO, passing a move is actually is illegal, but the timing of a move by the games manager means that a player may intentionally pass, which may be regarded as cheating. To get over this problem, a parameter called Compensate can be set, so when a player passes a move, the other player gets as a compensation more than one move.

2) Ghost. This is a fluid game. The board illuminates four points (the Ghost), and then moves the Ghost, by repeatedly switching on a point that is a neighbour of one of the illuminated points, and switching off one of the illuminated points. The players try to 'catch the Ghost', by touching one of the illuminated points.

3) Li/eI.This is a fluid game, i.e. the state of the illumination of grid points changes even if the players do not play. Each fixed time period (generation, a settable parameter), the games manager checks for each point how many of the eight points around it are illuminated, and accordingly decides if the point is going to be illuminated in the next generation. Thus the pattern of illumination of the grid points changes each generation. This is implemented by setting a time mark for a generation period and the game specific check (step 4 in the central loop) performs a generation step when the mark passes. In parallel, the player(s) can switch on or switch off points by pressing them.

Life] can be played in a 'kill' mode, in which the player tries to 'kill' the board, i.e. switch off all the points, as fast as possible, or in 'keep alive' mode, in which the player tries to keep the board 'alive', i. e. keep at least some points on, as long as possible. Adjusting the various parameters makes the task an interesting challenge.

4) Life2. Like Lifel, but the points are of two colours, and each player tries to switch off all the points of the other colour.

5) Touclt. Single player game, mainly testing reaction time and accuracy. The games manager switches on a few points (1 -4) one after the other with a short time gap, and then switches them off. The player needs to press the last point that was switched on before the next point is switched on or all of them are switched off By changing the time gap between switching the points on, the number of points and their pattern, the player can fit the game to his own level to make it a good challenge.

6) Symmetry. Single player game. The games manager switches on a pattern of points on one side of the grid, and the player needs to press the symmetry related points on the other side of the grid. Parameters like the number of points in the pattern, the time that is allowed for doing the copying and the kind of symmetry operation that the player need to do are used to match the difficulty level of the copying to the level of the player.

7) Clearlt. The game starts with an equal number of points illuminated in each of the two colours, but otherwise randomly distributed on the grid. Each player in his turn presses an empty point, and the games manager switches of all the points of the other player's colour 9 which are a chess knight move away from the pressed point, and points of the current player's colour which are one diagonal move further. The winner is the player that switches off all the other player's points first. This game is an example of a game when pressing a point never affects its illumination.

8) FiXt. Each player in his turn presses an empty point which causes a pattern of points around this point to be switched on with the player colour if they were off, or reverse their colour if they were on. The winner is the player that has more points when all the points are switched on. This is another game that cannot be really played on old- style board, because each move causes large number changes on the grid.

9) FindThem. A memory game. In the beginning of the game the games manager switches on an equal number of points in both colours but in a random pattern for a short period of time, and then switches all of them off. Each player in turn tries to switch on a point of his own colour by pressing a point. If this point was switched on with his colour in the beginning, it is switched on. The winner is the player that first switches on 9 points.

10) CountLines. Each player in his turn switches on a point of his colour by pressing it. A player is ipt allowed to press in two successive turns two points that are too close to each other (the distance is a settable parameter). The winner is the player that when all the points are switched on has the larger number of straight lines of four points of his colour.

11) Visiput. Each player in his turn switches on a point by pressing it. A player is allowed to press a point only if the point is 'visible' by points of his own colour at least as it is 'visible' by points of the other colour, where 'visible' means connected by a straight line of switched-off points. The winner is the player that succeeds to switch on more points. The games manager checks the games after each move, and if it can determine for each unilluminated that only one player would be able to press it, it switches on all the unilluminated points to the colour of the player that can press it, and finishes the game, thus saving the players the boring task of switching-all the unilluminated points after the result of the game is already known.

12) Go. Like in Visiput, the games manager finishes the game when it is clear which part of the grid is controlled by whom. Because this is a complex operation in Go and the heuristics that are used may get it wrong, this feature is controlled by several settable parameters, and can also be switched off.

to

Claims

I An electronic board comprising:

a grid of gridpoints on a flat surface, where each gridpoint is a visible element which is capable of detecting when it is pressed, and can be illuminated in at least two different colours by an illumination source inside or below the surface; and a game manager made of a CPU and memory, connected electronically to the grid points and illumination sources such that it has complete control on which grid point is illuminated and in what colour, and it is notified whenever any of the grid points is pressed, and a computer program which is executed by the CPU, which manages two or more games by displaying the current state of the current game using the illumination sources to illuminate a pattern of grid points on the grid, and changing the pattern according to the rules of the current game in response to a player pressing one of the grid points.
2 A games grid board as described in Claim 1, which also has a control area, containing input devices and character and digit display which are connected electronically to the games manager, which is used by the users of the board to set the current game and possibly various parameters, and by the games manager to indicate what is the current game, the current score and other information.
3 A board as described in any preceding claim, where when a point is pressed the games manager potentially changes the illumination of other points according to the rules of the current game.
4 A board as described in any preceding claim, where when a point is pressed the and the rules of the current game require it, the games manager checks if this point corresponds to a legal move according to the rules of the current game, and if it is not legal does not perform the move.
A board as described in any preceding claim, which when the rules of the current game require it, changes the illumination of the grid points even if the players do not press any point.
6 A board as described in any preceding claim, where pressing a point does not necessarily changes its illumination even when it is a legal move according to the current game.
7 A board as described in any preceding claim, where the plavers use, hold or wear a special I I implement vv-hich identifies which player is playing bv communicatin(y with the board.

7 A board as described in any preceding claim, which checks after each change if the game is finished, and if it is indicates it to the player(s).

8 A games grid board as described in any preceding claim, which when a player presses a point which is not allowed according to the rules of the current game, flashes all the points that are allowed.

9 A board as described in any preceding claim, where the illumination- of a grid point is done by discreet sources of light.

A board as descried in any preceding claim where the illumination of each grid point is done by a pair of LEDs or a bi-colour LED.

I I A board as described in any preceding claim, where the detection of pressing a grid point is done by a discrete sensor in each point.

12 A board as described in any preceding claim, where the detection of pressing a grid point is done by a membrane keyboard.

13 A board as described in any preceding claim, where pressing a grid point is done by a special implement.

14 A board as described in Claims I -11, where pressing a point is done by special implement that causes a short circuit which the board uses to identify the point that is touched.

A board as described in any preceding claim, Rifther means to determine which of the players touches a grid point.

16 A board as described in Claim 15, where which player touches a stone is identified by another special input button that the player presses at the same time or before he presses the point.

17 A board as described in Claim 15, where the players use, hold or wear a special implement which identifies which player is playing by communicating with the board.

18 A board as described in any preceding claim, further means to load into the board additional software.

19 A board substantially as described here with reference to figures 1-3.

Amendments to the claims have been filed as follows CLAWS I An electronic board comprising:

a grid of gridpoints on a flat surface, where each gridpoint is a visible element which is capable of detecting when it is pressed, and can be illuminated in two different colours by an illumination source inside or below the surface, and a game manager made of a CPU and memory, connected electronically to the grid points and illumination sources such that it has complete control on which grid point is illuminated and in what colour, and it is notified whenever any of the gnid points is pressed, and a computer program which is executed by the CPU, which manages one or more games by displaying the current state of the current game usinc, the illumination sources to illuminate a pattern of grid points on the grid, periodically changing the pattern according to the rules of the current game, and changing the pattern in response to a player pressing one of the grid points.

2 A board as described in Claim 1, where in one or more of the games in each period the games manaecr checks for each point how many of the eight points around it are I - i'lluin'n i Ated, and accordingly decides if the point is going to be illuminated in the ne>;!, period, the player(s) can also affect the illumination state of a point by pressing it, and the task of the player(s) is to keep some points illuminated as long as possible, or to cause all the points to be switched off as fast as possible.

3 in one or mor 3 A board as in any preceding claim, where e of the -ames the board illuminates an additional point in each period of time, and the player(s) need to press the last point that became illuminated before the next point becomes illuminated.

4 A board as in any preceding claim, where in one or more of the aames the board L__ I 'llum, I I I i ing on inates a pattem of points and then moves each period of time by switch' one point near one of the illuminated points and switching off one of the illuminated points, and the players need to press one of the points while it is illuminated.

A board as described in any preceding claim, where pressing a grid point is done by a special implement.

6 A board as in clairn 5. where pressing, a point is done by special implement that causes a short c'rcu't wh'ch the board uses to identif 1 1 1 y the point that is pressed.