Wooden Chess Board with Reed Switch Piece Recognition and LED move indicators


Please note the projects described in this site were developed 2017 and therefore I cannot provide much in the way of meaningful support.

The information provided should be taken as a series of helpful suggestions. This site does not provide a complete description of how to build a chess computer, just a collection of hints.

Many people have built this project, but with their own variations. To build one you will need to have programming and electronics experience, or be prepared to learn, a lot!

Two designs are suggested on this site. One uses just a Pi and the other uses a Pi for the chess engine and an Arduino to control the board. My original build used the Arduino, the Pi only route is probably the more elegant, and you will see that Fernando has succeeded in implementing it. See the Recent Builds Page.  So the choice is yours:   The PI + Arduino route is easier to build,  the Arduino is more robust and in particular seems able to manage I2C devices more reliably. Also by building the Arduino as a board controller (a sort of chess keyboard) you separate out the interface from the chess engine. However the PI only design is more elegant.

This site describes a fully working chess computer that recognises piece positions using reed switches and signals its move using a LED on each square.

It runs from an Arduino which controls the board, connected to a Raspberry PI which runs the chess engine Stockfish and a chess rules library called Chessboard. It is completely self contained, just plug it in, press the green button and you are playing.

Since building this version I have redesigned the hardware and I am part way through the build. However after many hours of work, I have stopped work on it and moved on to other projects.  The new design is here   I think it is fundamentally sound, I just ran out of time to get it to work.

If you are not sure if you have the skills to build this project try building the Noughts and Crosses project. Full instructions are given and I have built a fully working version, also have a look at Beginners Start Here.

Key Features:

Play chess by moving pieces  and the computer signals its move using by flashing an LED

  • Stockfish chess engine with a maxiimum rating of GM with an ELO level around 2900
  • 21 levels of play
  • Set personality: agressiveness and cowardice
  • Play as black or white
  • Play human vs human
  • Validates moves against full moves of chess, signals error & allows re-move
  • Recognises and makes special moves: Castling; En Passent, Pawn Promotion
  • Provides hint if stuck
  • Option to save game as pgn

How it Works:

The next few pages explain how it works, there are two parts:

Harware: electronics and the board

Software: The programs that drive it

Why an Arduino and a Raspberry PI?

An Arduino is great for real time control of the devices on the chess board, but it does not use a conventional operating system like Unix/Debian/Raspian. Therefore Stockfish and most other strong chess engines won’t run on it. I believe there are a few chess engines that do run on Arduino http://chessprogramming.wikispaces.com/Arduino  , but they will not be as strong as Stockfish.

My interest in building chess computers started with Arduino and at the time the Raspberry Pi had not been released. Six months later it was and I realized I needed a different computer so I added the Raspberry Pi to run the engine.

On reflection I think this remains the best approach. Each device does what its best at. The Arduino controls devices and the the PI runs complex software. In practical terms it allows you to build and test the Arduino board as a separate module and then add the Pi to drive it.

I have put considerable effort in trying to build a version that will run on just the Raspberry PI with no Arduino,  and I explain how the new approach here.

However although I think the design is sound I have not been able to get it to work. I have built a noughts and crosses game that uses a sub-set of the design but I cannot scale it up. This is probably due to failings in my electronics ability.

However the first version that uses a Pi and an Arduino works well and now that I have a great board that I can barely beat on level 3 out of 21, I have no reason to build another one.

I see that some people are designing robot arm playing chess computers, that sounds really cool. In that case I would use an Arduino to control the arm, board sensors etc and use a Raspberry Pi to run the chess engine.

Why the Stockfish Chess Engine?

Its the most powerful configurable Open Source multi-platform robust Chess engine

See here for more detail.

“I know what you’re thinking, punk. You’re thinking “is it mate in six moves or only five?” Now to tell you the truth I forgot myself in all this excitement. But being this is a 64 bit Stockfish, the most powerful chess engine in the world and will blow you defence clean off, you’ve gotta ask yourself a question: “Do I feel lucky?” Well, do ya, punk?”


Original inspiration from these sites:



Tony Whitby’s site, now defunct

Which set me off building a USB chessboard for connection to a PC based computer program. After that the next step was to build a complete chess computer.

71 Responses to Wooden Chess Board with Reed Switch Piece Recognition and LED move indicators

  1. Jimmy says:


    What a great project. I have a similar board that I have built. I’m using a teensy with some code from Berger’s Solus to monitor the board matrix, and I have written a stockfish interface in python also. I’d love to share what I’ve learned in the process and also learn more about your project. Thanks for the great video demo as well.


  2. Michael Lang says:


    I would like to build this “Arduino RPi Stockfish” chess board. Is it possible to get more detailed information?

    Regards, Michael

    • maxim says:

      See my other two replies.
      I would suggest you start by building a Reed based USB board. There are detailed instructions for this on the site:
      Magnetic USB Chessboard (Solus Chess) see the links page. Berger, the guy that runs it has provided detailed wiring diagrams

      My other suggestion is that you may not be best to use an Arduino plus a Raspberry Pi. I used two because neither did a complete job.However new boards are coming onto the market every day and I have just ordered a “Beaglebone Black” board. That looks like it might do everything.

      I will add a post to the site when I know more.

  3. Michael says:

    Thanks Maxim,

    I will wait on your experience with the “Beaglebone Black” board!

    Try the “Mysticum” chesscomputer on my website!

    Regards, Michael

  4. peter says:

    hi where can I buy that chess computer?

  5. peter says:

    how much would a computer like this cost me?

  6. maxim says:

    You cannot buy this chess computer you would need to make it and program it.
    I hope to be able to publish how to make one with code on a Raspberry PI (see design ideas section).

    The cost of the electronic components will be about £90, the major costs are:
    Raspberry Pi £30.00
    Port Expanders £2
    4X20 serial lcd £21.83
    64 LEDs £5.12
    Breadboard £8.00
    64 Reed Switchs £20.00
    Magnets £3.99

    The prices for reed switches and LEDs are for 100 of each on ebay
    Plus wires & connectors.

    This assumes you make your own board and does not include the cost of the materials for the board and the pieces,

  7. koks says:

    Can you please post a video showing the inner part of the board and the bottom part.

  8. Ahmet says:

    how to solve “Pawn Promotion” problem, are you using additional button?

    • Max says:

      Ahmet, no real problem, the board has four colored buttons and a display (see section on hardware) when a pawn is eligible for promotion the system gives the alternatives: Q, R, B, K and the user chooses.

  9. Ahmet says:

    what your main Raspberry pi’s OS?

  10. Paddy says:


    I am attempting to make a chess playing robot, I would like to build an arm but I think this is beyond my capability so I am making a cartesian robot (similar to a gantry crane). I am not very experienced in this type of work and I have found your website very helpful. So what I am wondering, in comparison to your project would you advise that I use the raspberry to run the chess engine and the arduino to control the movement of the robot in the X, Y and Z axis?

    • Max says:

      Paddy, I think you could do it either way, but I would personally run the gantry crane from an Arduino and would use a motor shield like the excellent Adafruit shield to drive the motors: http://www.adafruit.com/product/81.
      you could do more than just x,y movement on the Arduino. For example you could have functions like : pickupiece(x,y), movearmto (x,y), placepiece(x,y), or more complex functions made up of functions like removepiece(x,y) or even castle(colour, Side) using this approach you could completely test the board separate from the engine. I would be interested to see how you get on. I think your biggest challenge will be to reliably pick up and place pieces.

      • Paddy says:

        I have the design for the robot completed including the grabber which I think will work well and accurately. I think I will be able to get the robot working well physically but I might struggle because I am very inexperienced when it comes to programming of any type. I have downloaded Python 2.7, Chessboard and Stockfish 5 but I do not know where I need to install each for them to run correctly.

        • Max says:

          I haven’t touched the code for over a year, but from what I remember Chessboard goes in the Python directory and Stockfish will end up in the right place if you use a standard Linux/Raspian install $sudo apt-get install stockfish. You then need to make sure you use the right file name in your Python program. you say you are “very inexperienced when it comes to programming of any type.” Maybe you should work through the book “Python Programming for the absolute beginner” by Michael Dawson. It will teach you lots of the things you need to know for your project.

          • Paddy says:

            Max, do you think this project would work as well if I excluded the Raspberry Pi altogether and ran the Chess engine off of my computer, connected to my the arduino? I am finding using the Raspberry Pi quite difficult and am hoping to make the project a bit easier to complete.

            • Max says:

              Paddy. Connecting from a computer is the same a connecting from a PI. I suggest you approach this step by step. First are you able to communicate between the Arduino and a simple Python program running on the PI? if you can’t here’s how: http://playground.arduino.cc/interfacing/python.
              If you can do that then on the Pi (or your computer) you will still need to write a Python program that manages the chess engine and the ChessBoard library if you are going to build a self contained chess computer. The example Python program on this site gives you the bare bones for doing that.

  11. Amey says:

    can you provide a source code for rasperry pi??

  12. Eric Warolus says:

    Congratulations on achieving your chessboard.

    For some time, I plan to build a chessboard with USB port (Berger soluschess) adding LED on a wooden chessboard.
    This board can be connected to a PC, tablet or raspberry pi.

    Your website is very good informative, already thank you for all that information.

    For the detection and display, I’ll buy the electronic components

    a teensy ++ 2 (enough for dectection square, but for the lighting of LED?)
    the reed switches,

    Can you just give me more information
    about Port Expanders £2 and Breadboard £8 ?

    I just got a rasbperry pi 2.


    • Max says:

      I control all the LEDS using the MAX7219CNG LED display driver (port expander). To drive the MAX7219 you need only 3 pins from the Arduino.
      See this link for an example tutorial.

      The breadboard is just to hold the MAX7219 and join the connections not very elegant.

      • Eric Warolus says:

        Thank you for your quick response.
        I do not plan to use an Arduino.

        If possible, the connection between the board and PC, tablet or Rasperry ft 2 is made only by the USB port.

        To your knowledge, there is a micro controller USB programmable that manages the detection of movements and the lighting of the LED?

        Thank You

        • Max says:

          Yes the best micro processor to use to control the board and connect via USB is an Arduino. I used an Arduino UNO but I think either and Arduino nano, or a Teensy might be better.

  13. Paul says:


    Thanks for putting up your excellent work.

    I pretty much have the python you have made available adjusted for what I need and found it was a great start for interfacing between a UCI engine and the ChessBoard module.

    Do you have any objections when I am done of me making my version of the code publicly available (with due credit to yourself of course)?



    • Max says:

      Paul, no objection to you publishing code, mine was also based on the work of others. What is the URL of your site, I am interested inthe architecture you used for the board. Max

      • Paul says:

        Hi Max,

        I haven’t put anything online yet and at the moment am getting the software sorted out – need to set the skill and cowardice/aggressiveness options. I have only been working on this a few days and am happy it is working with Stockfish 6 which needed compiling from source and has hooks in place for input from board, output to board/display as appropriate.

        Next job is the electronics, at the moment I think I can treat the board inputs as an 8×8 keypad on the RaspberryPi using an I2C port expander – so can avoid having to add a Teensy or Arduino into the mix. LEDs – have decided to go for 16 LEDs side/bottom rather than each square – again driven off I2C. For a display I am likely to use a 128×64 OLED display with yes an I2C – in theory I can use 7 MCP23017s…

        Once I am happy with the code/electronics side of stuff I then intend to build/bastardize a board.

        Its early days at the moment, parts are incoming from China etc and I am in no rush as this is for fun.

        Once stuff starts going online (in a few days I guess) I will let you know the URL.

        • Max says:

          Paul, Your approach should work and the port expanders should give you enough connections. You will be aware that you cannot treat the chess board as a simple 8×8 matrix as in play some reed switches will already be activated because they already contain pieces. This leads to “ghosting”. You will need to add diodes see: https://sites.google.com/site/bergersprojects/reedcb/matrix
          Treating the board as a matrix is the more elegant solution. However I hate soldering and once you add in the diodes you end up with 4 soldered connections per square. (two each for the diode and reed switch) I ended up going for the the brute force option using a I2c centipede board which allows for 64 direct connections. More wire, but only 2 solders per square and very simple testing. It connects by ribbon cable so the wiring is simple. Then in software I can directly address each square.
          For the LEDS I went for the full 64 which you can treat as a simple matrix, because only one is on at any one time and with the MAX7219CNG LED driver its easy to wire.
          But it sounds like you are on the right track. Please keep me informed.

        • adam says:

          hello paul,

          How’s it going with the chess board project? Is it still underway for publishing? would like to build a stand alone board as well.

          wish Max would post a tutorial on his build. 🙁

          Thanks Max and Paul for the work you’ve shared and/or are planning to share! 😀

  14. Narayanan B says:


    Very nice project and beautifully executed! I would like to build one as well and have questions regarding the design and placement of Reeds. I live in the US. Can I call you at a time that’s most convenient for you? This should not take more than 15 minutes.



  15. James says:

    Okay, this is great. I had a kasparov chess computer in the 80s and it was the bomb when I was at school, although got very slow at the higher levels and I kind of outgrew it.

    Now I have young kids getting into chess and I would love to buy a cool wooden chess computer like this. I swear there is a market for this – seriously think about putting something like this up on kickstarter.

    A great side project – you could seriously pump out a few hundred of these a year …

    • Max says:

      I looked at this. Until a few years ago you could buy good quality wooden chess computers, but since the advent of PC, Phone and tablet chess programs, the market for them has collapsed. You can still get them on ebay.

  16. Adrie says:


    Very nice,

    Can I buy a nice Board, please?
    Or can you make one?




  17. Max says:

    I am afraid you will need to make your own. I do not sell or make for others. Alternatively you could buy a wooden Mephisto Exclusive Chess computer on ebay. They are not made any more and go for around £200. They are not as strong as Stockfish, but will beat most players.

  18. Hi,

    I wondered if it would be possible for you to write more detailed instructions so that we could copy your design? I’m particularly interested in how you set up the wiring. I have done some simpler Raspberry Pi projects, but nothing this complex so far.



    • Max says:

      Jennifer. I have redesigned the chessboard with a simpler design. However there is still a lot to be done. I suggest you start by trying to wire up a simple 3×3 grid, perhaps building a tic-tac toe game (Noughts & Crosses in English). The MCP23017 controls the reed switches and the HTK1633 controls the LEDS. I will put up more detail on the page in the next week or so.

  19. Brian says:

    I have built a board similar to this, and would like to offer a few thoughts from my experience.
    I initially mounted the reed switches horizontally, but found them to be very hit and miss because they are activated by the magnet at each end of the switch rather than the centre. Mounting them vertically works much better.
    Although it can all be done with the Rpi, I still used an arduino on the board because it can then be used to connect to Pi or to a pc running Arena. Would also be easy to upgrade to other single board computers that may become available.
    I wanted the leds to light on four corners of the selected square, but you then need a 9*9 led array. I used 2*MAX2719 kits and dumped the led matrix that they were supplied with..
    I modified the open source picochess (https://github.com/jromang/picochess) on the raspberry pi to interface with my diy board. and it works really well, although I don’t yet have all the functionality working correctly.
    For the board I used a wooden tournament board from ebay (£22).
    drilled 3mm holes at each square corner for the led’s and another hole from the back of the board in the centre of each square (not all the way through) to mount the reed switches and diodes
    To allow space for the electronics and wiring under the board I will add wooden mouldings around the edges.

  20. Charlie says:


    I’ve been I sourced by your project and I’m planning my own chess board computer. I haven’t started and had an idea of instead of having indicators to light up the computer moves, to have the programme announce the moves via a small speaker.

    I just wanted to see what your thoughts were on it and if there was any obvious reason as to why this may not work/be practical. I was also hoping for some advice on how it would be possible to do this.

    • Max says:

      It should be very straight forward to get the computer to announce its move and any other instructions, for example starting the game, saying “Check” or giving an error message. You could either do it using pre recorded sound snippets, or voice synthesis. The starting point is Python Program that runs Stockfish. In the example code the user types in the move and after calculation the program prints its move or other instruction. In my board implementation, move input is done by via the reed switches and output via LEDS on the squares. You just need to send the output to a speech module. So technically straight forward, although I think I would find it annoying. If you are using speech why not go the whole way and use speech recognition (like Jasper) to recognize the human speaking a move and speech synthesis to play the computer move. The really helpful Adafruit people have a tutorial on that. That way you don’t need a special board.

  21. Alex says:

    MAX, I’m really interested in the project, when I first saw the topic I’ve remembered about the USSR-time chess computer called Strateg. I’ve got one but without the brain part… I would like to send you some photos (an e-mail) of the PCB inside – for your advice about the infrastructure – what can be used (if it is possible) & what should be replaced.

    Sorry for my english – had no practice for a long time

  22. Dan says:

    I installed Stockfish on my Raspi using apt-get. How do I alter the windows example to get it to run? Thanks.

  23. Fritzmann says:

    Hey look at this new kickstarter project, I just found. They connect a reed switch board to lichess, very interesting. What do you think about it?


  24. Daniel Escobedo says:

    Hello, Max
    Thanks for this site, you’ve put lots of information here.
    And I’m now determined to build my own chess computer.
    But After looking at other sites I’m not sure where to begin.
    So, I have some questions that I hope that you will point me in the right direction.
    I would like to be able to use Arena if possible.
    1- Which way is the best way to go?
    2- Teensy Board (advantages and disadvantages)
    3- Arduino Board (advantages and disadvantages)
    4- Mysticum
    Chess board

  25. Daniel Escobedo says:

    I forgot to mention the
    raspberry p1 3 b+ (advantages and disadvantages)
    I know nothing of electronics, I’m a Catia Nc programmer

  26. Max says:

    Arena is a pre built GUI and if I remember correctly you can just plug in Chess engines like Stockfish and others. Arena and the chess engine would be your Chess computer. The wooden chess board would be dumb and essentially act as a specialized keyboard.
    So you would enter your moves by moving a piece on the board and the board would then send the move to Arena that would validate and display it and then pass it to the chess engine to calculate the response that is then sent to the board.
    Physically you have a computer with a screen running Arena and then you plug your chessboard into that using the USB port and communicate serially.
    You will see that Arena supports the DGT Chessboard and the Novag Citrine Chess computer in this way.
    You would build a your own ” USB Chess Keyboard” and plug it in.
    In fact that’s where this whole project started.
    See: http://sishchess.blogspot.co.uk/p/building-sish-board-tutorial.html
    for the original website, there but inactive.
    or for a full description of how to do it see Bergers excellent site:
    or Brian’s site mentioned elsewhere.
    For this application the best platform is Teensy, which is essentially an Arduino on steroids. More memory, more processing power.
    Once you have built this USB Chessboard you could then write your own version of Arena running on a Raspberry Pi and running a chess engine like Stockfish, but with a limited display to just prompt for moves etc.
    And that’s what my system was originally.

  27. Daniel Escobedo says:

    Thanks Max for your fast response,
    One more question please,
    what then is the difference of using
    Raspberry Pi Vs Teensy.
    Is it just more power and speed?

  28. Max says:

    Its a question of choosing the right board for the job. If you want to control lots of physical devices in real time then an Arduino like board such as the Teensy is ideal. Its got loads of pins for connection. easy libraries for making connection and is very robust. You can switch it on and off without worrying about power down. But its not so good for running or developing large amounts of layered software. It doesn’t have an OS, doesn’t support Python or any regular chess engines. But there are engines that run on it. See Arduino Chess on this site. http://chess.fortherapy.co.uk/home/arduino-chess/.
    The RPi on the other hand is a full blown Linux machine that will run loads of standard layered software. You can connect hardware, but its a bit precious and its easy to blow the board that way if you get the voltage wrong or there is a surge.
    That’s why in my original design I used an Arduino to control the board and an RPI to run complex software. In my second version of the project I tried to run it all from the RPi. I think I have demonstrated that its possible, but not necessarily reliable or very forgiving.

  29. Daniel Escoebedo says:


    Looks like i will go with Teensy,
    for my 1st try.

  30. Hank says:

    Hi Max,

    I, too, am attempting to recreate this project using the RPi and the MCP port expanders. You mention that this approach is both unreliable and unforgiving, any way you could elaborate a bit? Do you think that it’s worth attempting a wholly RPi design, or would the addition of an arduino help to remedy some of the issues with reliability?


    • Max says:

      I think having an Arduino control the chess board and an Rpi run the chess engine is the most achievable way forward. In theory an RPI could do everything, but I have found it difficult to do. The tic-tac-toe design using a 3×3 matrix works and includes all the elements required for an 8×8 chess board, but I have not yet been able to build a reliable 8×8 version.
      Arduinos are much more robust then RPIs.
      Alternatively you could build a complete system on Arduino using the Arduino Chess code described on this site. It would however not be as strong as Stockfish

  31. Roshan Sivakumar says:

    What I am trying to do is send a move from my Arduino to a Rpi which runs the Stockfish engine and retrieve the best move from the engine. There are 2 players
    one is the human and the other is a robot.

    1.should I send only the move that has been played or all the moves from the beginning. Do I need to send the moves that have been played by the robot(moves after being instructed the best move from the chess engine) and human or only the human

    2.Can I send the moves in either SAN or FEN or is there a specific notation that I need to send them.

    3.I was going through the code in the following link : https://github.com/zhelyabuzhsky/stockfish/blob/master/stockfish.py
    , When i run the code in the above link i get the error [WinError 2] The system cannot find the file specified even though I replaced the path = ‘stockfish’ with path = ‘C:\Users\Home\Downloads\stockfish-9-win\stockfish-9-win\Window'(please note that I am testing this in my laptop fisrt before moving to rpi). Also can anyone explain what the subprocess library does. As far as I can understand it is used to run an engine in a computer am I right?

    • Max says:

      Have a look at my code at:
      My python program
      Stockfish has no memory of previous moves so you send it the current position and it returns the best move.
      You will see from the listing that I send the chess engine a string containing all moves in SAN format. The alternative is to send the board state as a FEN. However I found a bug in the “ChessBoard” library that meant I could not use FEN.
      I have no idea about the github code you reference, its not mine. However the sample code I give runs on the PI and you just get the Arduino to send you a move from your board instead of typing it in.

  32. Ryan says:

    I’m looking to cast my own set of Lewis chessmen (and also try to use them with Hall effect sensors) as you briefly mentioned on the Hall Effect sensor page. Could you give any information on what material you used to cast your Lewis chessmen and how you got the great colors with black detailing?

  33. Wal says:

    Hi Max,

    thanks for inspiring me to have a go at this project. I decided to give it a go just over two months back, and have got the machine to a workable state now, albeit still rough. I’ve uploaded a video of the box to YouTube here: https://www.youtube.com/watch?v=n7CTtXflS9c

    I managed to get it working with FEN based notation, and came across some of the same problems you did with multiple MCP23017s – interrupt wouldn’t work with more than 3 connected, as far as I could tell. I still have a lot of tidying up to do, but for now it works – it’s certainly better than me at chess!

  34. Max says:

    Great implementation! Well done looks really good.

  35. Ante Salov says:

    Hi Max,

    I did raspberry pi only based digital chess so leave me your e-mail if you want to know more about it. I already written here when I was doing project and get stuck. But in the end I managed to make it and it works. If you want more details leave a mail.

    Best regards.

  36. Ansh Aggarwal says:

    Hi Max,
    I would like to build this project but I do not understand the instructions very well. They are a bit confusing to me. Could you please email me and help me out. I have both Raspberry Pi 3 and Arduino Uno.

    • Max says:

      The site is designed to give some useful tips, but support is not provided. Unless you are an experienced programmer it is recommended that you start by building the NOX project first. This is much simpler and is explained in detail and will give you all the skills you need to build the chess set.

  37. Luhit Young says:

    Hi Max,

    This project of yours has intrigued me for 5 plus years. The pandemic and stay-at-home orders finally gave me the final push to start it.

    I have most of it working, sans the buttons to control the game. I have a short video where I purposely lose here: https://www.youtube.com/watch?v=CpMRReEnYvU.

    Note: due to the lack of buttons, after the game ends on a checkmate, the computer just resets for a new game and you can see this on the instructions on the LCD screen.

    However, before I commit more time to this project, I want some advice regarding reed switches and piece proximity.

    I built this project on a small square board 28cm X 28cm (11″x11″) and although on my initial test programs worked detecting single pieces with the reed switches and lighting the accompanying squares on the board, chess requires at most 32 pieces to be on the board at once and in close proximity to other pieces.

    In the worst case scenario of piece proximity, one square can be surrounded by 8 squares/pieces and those 8 pieces SHOULD NOT affect the reed in the middle.

    So, in some squares on my board, a piece can close the reed switch of an adjacent square which confuses the program. I have tried minimizing this effect by bending one of the reed switch ends AWAY and perpendicular to the board, but having little effect. And, in the proces, I killed about 5 of the switches which I now have to replace.

    So, I have a few questions for you:
    1) In your experimentations, did you encounter a similar issue?
    2) Have you found an “ideal” board size where the piece proximity does not affect reed switches from other squares?
    3) Since both ends of the reed switches can be activated by a magnet, are there spots on your board that would activate a square even though the piece would NOT be in the square?
    4) If so, is there a better way to arrange the reed switch to prevent this “false triggering”?
    5) Finally, is the case for using 64 reed switches still there (economically feasible and simplicity) or are there better non-powered alternatives that I am not aware of?

    Note: I am using regular 10mm neodymium magnets and “normal” reed switches.

    Any advice regarding this would be appreciated.

    • Max says:

      Congratulations for getting this far. Let me answer your questions:
      1) In your experimentations, did you encounter a similar issue?
      I did have to experiment with the positioning of the reed switches to get it right and I found that as desribed on the Building The Chess Board page the switches need to be offset from the centre. You can see that more clearly if you look at the TicTacToe project. There is a photo that shows positioning.

      2) Have you found an “ideal” board size where the piece proximity does not affect reed switches from other squares?
      I went with 50mm squares, which is a standards size for chess boards and goes well with 95mm / 3.75″ chess pieces. If you squares are smaller you will get these false triggers.

      3) Since both ends of the reed switches can be activated by a magnet, are there spots on your board that would activate a square even though the piece would NOT be in the square?
      Its the same principle, if you position the Reed switch offset diagonally along the LED diagonal on a 50mm square you get no false triggers. Also different margenet sizes and makes may have different strengths, but the main issue is positioning.
      4) If so, is there a better way to arrange the reed switch to prevent this “false triggering”?
      5) Finally, is the case for using 64 reed switches still there (economically feasible and simplicity) or are there better non-powered alternatives that I am not aware of?
      I have not found a solution that is better, or more cost effective than Reed switches. Some people have tried hall sensors. The ideal might be RFID, where there is a tag in each piece, but then you need a 64 readers and you have the same false read problem I have not found a “matrix” RFID reader. The two most promising technologies are pattern recognition or maybe touch screen. Both are much more complex to implement.
      The Rolls Royce solution is the patented DGT technology where the pieces contain a LC tuned resonator on a ferrite rod, in the frequency range of 90-350 KHz. Boards cost £600 plus.

      I have found that the Reed switches are highly reliable once you get the spacing right.

  38. Luhit Young says:

    Thanks for the reply, Max.

    I will keep tinkering and hope to let you know when I complete the project.

    • Luhit Young says:

      Hi Max.

      I hope you are doing well. Thanks to your videos and guidance, I finished the chessboard using the RPI-only build. So, it is not just “viable” as you mentioned, it is do-able!

      I have added a few bells and whistles to the board and I am very pleased with the result.

      I am a professional software engineer but this was my first physical electronic project ever. It has given me the confidence to try my hand at other projects such as converting an old Roomba into a phone remote controlled robot with an RPI Zero W and making an RPI Plex Server for my entire movie collection.

      My next project will likely involve some mechanical gadget to deliver candy to trick-or-treaters.

      I am in the process of making a video demoing my build and I’d like to help others make the project.

  39. 9acca9 says:

    Hi Max.
    A question.
    There is a way to connect this kind of board with a program like Arena Chess Gui?
    I know that is not create for that. But what you think about that? is possible?
    You have some links or info related to that?

  40. Brian says:

    I tried this using a teensy 2++ to control the chessboard reed switches and led’s. The teensy can be configured to act as a keyboard, so it was quite easy to send the moves to arena software.
    I wasn’t able to get the teensy to respond to moves sent by Arena to light the led’s, although I didn’t try for very long.
    I would be interested if anyone has any success with this.

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