GAME DESIGN - Reed switch and RF ID chip combo ?

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Hello all,

I’m new to electronics and Arduino, but researching how I may be able to create a game board with game pieces that interact with the board.

The simple concept is that a game piece would be placed on the board and the board would know where it was placed and what type of many potential pieces is in that location.

• Once placed, the game piece would identify itself to the game board as a particular type of game piece (possibly RFID…?)

• At the same time, the placement of the game piece would be noted by the game board in order to identify where on the board the piece was placed (reed switch…?) --note that magnetic placement would be preferred for the game piece connection as the game board may need to mount to a wall at times.

• The placement of the game piece on the board and the identity of the game piece type would be recorded by a game chip (Arduino…?)

• As the game is played, the game chip reports the data via wi-fi to an application on a mobile device (wi-fi sheild for Arduino…?)

My biggest question is whether anyone knows of any Spark Fun products that could handle the functions of the RFID concept mentioned above???

Bonus question would be if there is a better way to handle the game board placement indication outside of the idea of a reed switch?

A comparison for this type of game could be the ‘Skylander’ games with action figures (game pieces) that are placed on a ‘portal’ (game board) and then the game console (game chip) knows they have been placed and adjusts the game play accordingly.

However in my game concept, there will be many surfaces that the pieces need to be placed on, hence the need for the game chip to know the location of the placement on a board of multiple areas of play for multiple types of game pieces.

Thanks for any ideas/responses !

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This same project has been discussed before not too long ago. Use the search function here or you can use Google to expand your search.

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It sounds like you definitely need a way to tell one piece from another. How many different types of pieces are there ? I don’t see RFID as working, unless the pieces can be “set” so as to not interfere with each other.

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@ Codlink:

yes, I did search and found only an article titled ‘Electronic Boardgame’ in which they were discussing a game where the pieces would have physical pin connections to the game board, that is not a helpful discussion for my application as I will require magnetic connection of pieces to the game board as indicated in original post. If you know of another discussion I missed, please advise. Thanks!

@ Mee_n_Mac:

you are correct, I need a way to tell the pieces from one another. I was thinking RFID but I would need 20 game pieces with RFID tags (about $300) and then an RFID reader for each game board play position which would be about 48 game positions (about $1200)…is looking cost provibitive to use RFID for a game with 20 unique game pieces and nearly 50 game play postions with RFID readers installed. And yes, there is the challenge of game positions proximity with RFID, not sure how to limit the range of the RFID reader to just the immediate area of the game board play position. Also, the magnets used to attache the game pieces to the board may interfere with the RFID signal to the RFID reader…?

I would think a cheap and simple Reed switch installed in each of the game play positions on the board will take care of how to indicate where pieces are on the game board…but, identifying each of the 20 various game pieces at each of the positions is the challenging part.

FYI, I was looking at the Glass Tube RFID tags and the ID-3LA RFID readers avail here at SparkFun. It seems the glass tube tags have the nearest proximity read distance of about 1/2", and the ID-3LA reader requires an antenna installed (perhaps can shorten antenna length to limit cross ID to another reader? ) However, using these devices on 50 position board with 20 pieces is cost prohibitive.

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I was going in the opposite direction. Have 1 “RFID-like” reader for the entire board, have each piece respond only when asked. Alternately have the board broadcast a “who’s there ?” request and each piece responds within it’s preset time slot. Each piece would have to read it’s position from the board.

Now the above might not be easily done w/existing RFID tags. So my thought was to put all the board spaces on a bus (or 2). Perhaps something like RS485, whether hardwired or inductively coupled akin to NFC. Have each board space correspond w/a time slot and then each piece can answer w/it’s ID when the request is broadcast. Thus the board knows which piece is where.

Each piece can be a pretty low end micro, either battery powered w/a deep sleep mode or getting it’s power from the board.

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@ Mee_n_Mac:

I think I understand what you are mentioning…to have one single RFID enabled board with a stronger antenna to be able to read IDs of all the game pieces when it sends out the request.

However, how to the magnetic game pieces interface to the game board spaces to let the RFID reader query know where each piece is at any moment? Wouldn’t that mean that each game piece would need to be capable to transmitting a variable or some sort, telling the RFID reader “here is my game piece ID and also my location on the board”…?

Do I have that line of thinking correct?

Isn’t it more simplified to just insert a cheap RFID tag into each game piece and then develop some method for the placement of the piece on the board to send the RFID tag info as well as it’s position on the game board to an Arduino?

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OceanStudio:
I think I understand what you are mentioning…to have one single RFID enabled board with a stronger antenna to be able to read IDs of all the game pieces when it sends out the request.

However, how to the magnetic game pieces interface to the game board spaces to let the RFID reader query know where each piece is at any moment? Wouldn’t that mean that each game piece would need to be capable to transmitting a variable or some sort, telling the RFID reader “here is my game piece ID and also my location on the board”…?

Do I have that line of thinking correct?

Correct. All existing RFID tags can transmit some form of unique ID. That's the ID part of RFID. Getting a commercially available product to also (somehow) sense it's position and also relay that is an open question. Otherwise you have to have the board individually select which space to send RF to, or have some other means to determine the piece's location. Using some RF method for that is hard (?a network of switched antennae?), at least I don't know how to do it cheaply. It's having an "RFID reader" (or it's functional equivalent) for each board space. The Skylander games use a single "portal" (using NFC) for that reason ... I suspect.

OceanStudio:
Isn’t it more simplified to just insert a cheap RFID tag into each game piece and then develop some method for the placement of the piece on the board to send the RFID tag info as well as it’s position on the game board to an Arduino?

Perhaps, but a method to do that hasn't occurred to me yet. Since many pieces (I assume) will be on the board simultaneously, just knowing that spaces B, C, E, F, X, Y and Z are occupied isn't enough. Once you add "smarts" to the piece, you're past using a simple, available RFID tag. But given the price of a simple, cheap micro-controller these days, I don't see that adding some "smarts" to the piece increases overall cost that much. Certainly less $$s that using many readers or have some switched antennae network. Afterall what's inside an RFID tag ? An antenna, a low (micro) power power micro and ...

The question then is how do you get the micro in the piece to communicate w/the board ? A wired RS485 might be one such method. Perhaps you end up making your own custom RFID tag and use a commercial “far range, wide field” reader. The difference being that the custom piece can read it’s location on the board via pins or some other way**.

Right now is the time for a multitude of suggestions, keeping track of their pro’s and con’s (cost being one point of evaluation). I’m offering up one, or maybe more, such suggestions.

** one other way might be to mimic how multiple 7 segment LEDs are matrixed. Power is supplied to one of the segments but across all the LEDs. Ground is applied to only one of the LEDs but to all it’s segments. Only 1 segment will be at the intersection of power and ground so so get powered up. If the board can be divided into rows and columns, then only 1 piece might be powered at a time. Then you might use a commercial active RFID tag, one that get’s it’s power via “pins” and not from the RF field (similar to the EZ Pass transponder in your car). This method also keeps pieces, near but off, the board from responding to the RF interrogation.

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Is this game strictly one-at-a-time turn based, that is only 1 movement from board space to board space or from off-board to on-board (or the reverse) is allowed ? If so why not use your suggestion from above. That is use a Skylander type of “portal” to register the type of piece being placed for all off- to on-board moves. Then a simple “piece present” indication/detector is all that’s needed for all the board spaces. You could even use the same NFC reader tech Skylander uses. The piece could be magnetized and thus stick to a vertically hung board, that same magnet being sensed by a reed switch or Hall sensor at each board space. All that’s needed is an intermediate step before placing a new piece on the board, that is it makes a short stop at the “portal”. Perhaps the piece could be lit up to indicate something “special” has occurred. The board controller then keeps track of what piece was placed on what board space and it’s pretty simple to know that a piece has moved.

The only quirk is if a piece can capture another piece, as in checkers or chess. The board controller must catch the brief disappearance of a piece and conclude it was replaced instead of deducing that the capturing piece was removed from the board for some reason (or simply fell off).

Then it’s 1 reader ($30) for the whole board, 1 tag ($1) for each piece and 1 detector (??$), readable by the board controller, for each space. And of course a board controller plus WiFi (or other) link (???$$).