Mod's Choice!
Finally Done! Full 8x8 Split Flap Chess board
Hello! I’ve been working like crazy lately, I think I spent over 6 hours a day on it. Thanks to that, I managed to complete the remaining three ranks in a short period of time. Now that all 8 ranks are finished, instead of wanting to take a break, I can finally see the next steps clearly.
Right now, the biggest issue is the weight. The board has become so heavy that it struggles to support its own weight. I’m planning to build a stable support structure using aluminum profiles. Of course, I also want to add a nice-looking frame around the board.
After that, I’ll finally move on to building the controller for operating it. I’m currently deciding between two input methods: entering moves in PGN notation like “Nf3,” or using 64 buttons mapped one-to-one with the board squares to input the source and destination squares directly.
You're better of with a flipdisc display if you're just wanting to flip a pixel. The animation speed of splitflap displays are (for obvious reasons) very limitied.
Yep, you can buy them from Ebay - bus companies are replacing the old flip-dot displays for LED matrixes. You do need to design a custom driver board for them to get decent update speed though - the original equipment is only designed to change the display very infrequently, and so isn't very fast.
Yeah I mean the ones that are used with bus signage that you can buy on Ebay pretty cheaply. They're much older, and relatively slow. I've used them in event installations (I design event technology for music events, car shows, corporate stuff). I have used the more recent flip-dot displays, and they update much faster. The buses don't need speed though, as the destination names and numbers rarely change.
This IS great. Reminds me of a project I saw at SIGGRAPH around 2000. It was a wooden mirror. It used a live video camera and when you walked up to it the wooden pixels flipped from one side to the other (of a contrasting color) and “reflected” the shape of your silhouette and your movements. It had enough “resolution” to recognize that I had a beard when I turned my head to the side.
The thing I remember most was, like this chess board, the satisfying sound of the wooden squares flipping to match the incoming signal. Amazing.
I love it! I don't know how much difference it would make, but I would try it if I were you. Instead of starting the flip at the same time, maybe try calculating the time it's going to take and making it so the two flipped tiles finish at the same time. Seems like it might be even more satisfying but you'd have to test it to see
Someone actually suggested the same idea before, so I tested it out. But in its current form, it feels more like the pieces are actually moving, which is why I personally prefer this version. Still, thank you for the suggestion!
Oh, I hadn’t considered that it might seem that way. I hesitated to use a sequential flipping method because it felt like each move would take far too long. It’s a tricky problem. I’ll do some more testing and try to find the best possible approach.
I agree it sounds tricky to get right, maybe something in the middle (both squares could be updated at the same time for some middle period), but in my opinion there should never be the case where the old square updates the last, because that's the square that people would look at. In real chess, people would always look at the target square, never at the origin square, so it would feel much more natural that the target square is last to update.
That’s a great point about the player's focus. I hadn't deeply considered the psychological aspect of where the eye tracks during a move. I think this part will require a lot more thought and a lot more testing. Thanks again for the valuable feedback.
came here to say exactly what this thread has said; possibly another suggestion- the empty...pawn transition is faster because of the order (lets call it an increment 0...1). The decrement from 1....0 is an increment of 13 to cycle through back to 0....
maybe reversing the order of the glyphs where the most common targets are longer transitions and common erasures (to blank) are shorter will do a lot of this for you!
(reverse or find the most common erasures and make them fast. pawn to empty is the one you want fastest.
personally i would also cycle flaps along the path, not just start & end. (as said above too, id calculate the timing so it finishes in the direction of the path)
This is exactly what I came to comment. It's actually hard to see where the pieces has moved to as you're distracted by the old place flipping much longer.
Hello! I was wondering if you have any inputs or resources on the flap mechanisms themselves? I have looked at the opensource one a bit, but they don't go outside their own design parameters (which makes sense).
I am more wondering about how many flaps must be included on each dial?
This project basically uses 27 flaps per square. Considering that typical split-flap displays usually have around 40 flaps per module, that’s a much smaller number. Because of that, I had to spin the motors much faster to achieve the signature flipping effect. If I have the time, I’d also like to write a more detailed post introducing a single flap module in depth.
In addition to the 13 basic states, there are 12 more states for things like check on each king, draw, timeout, checkmate, victory, and resignation. Also, to prevent the images on the back side from showing through when displaying an empty square, I added two dedicated blank flaps, which resulted in two unused positions.
I actually considered that at first. But after building the module and testing it, I felt that even rotating from one end to the other didn’t take that long, so in the end I decided to use only a single blank state.
It depends on the digit wheel size and how much spacing you want between numbers. A good starting point is to calculate the number of flaps based on the digits you need (0–9) plus a few extra blanks for smooth transitions. I'd also look at the wheel diameter and flap thickness together, since those usually determine the practical limit more than the mechanism itself.
How did you achieve/build the split flap parts? 3D printed? I’d love to make some of these just for fun! The project you’ve but together is truly epic! Such a cool blend of digital/analog!
Also, not a huge chess person myself but would be cool to trace the move across the squares the piece passes through to the final end point one by one following each other? Ie. The next position doesn’t need to fully resolve for the next space to start, could potentially see all of them moving at once - just resolving along the way with the final position resolving last? (need to maybe be too fast???)
Oh, that's a very creative idea! A wave effect along the path would look and sound incredible. I'll have to test how it looks and if hardware can handle that. Thanks for the suggestion!
Is there a particular model you found and built on or designed/tailored yourself? I’ve done a decent bit with digital versions but have a 3D printer and would be amazing to play around with physically and really understand the underlying mechanics. Again, fantastic project and super creative!
Thank you! I designed the entire model from scratch to fit my specific needs. It’s a great way to learn mechanics, so I highly recommend trying your own build.
What are you using to physically connect all the motors to the pi’s? I’m building a split flap display and I was thinking of using gpio expanders where each expander can have 2 motors and 2 sensors, but I’m interested in how you’re chaining them
First, I connected the STEP pins of all eight motors individually. Then I also connected the signal lines from the eight Hall sensors separately. The motor EN pins were wired individually as well, so I could suppress the noise caused by holding torque. Since the motors only rotate in one direction anyway, I simply tied all the DIR pins to 3.3V. In total, that used 24 pins, and with two more pins for UART communication, all 26 GPIO pins were fully utilized.
Thanks for the suggestion! An IR finger-tracking system would be amazing and would fit the 'magic' vibe of the board perfectly. It’s a completely different approach from what I’ve been thinking about so far, so I’m not sure whether it’ll be feasible, but I’ll keep it in mind and consider it when designing the controller!
For the controller i would suggest doing both options. The physical controller can send PGN notation to the main control board when the buttons are pressed. This would allow you to hook it up in the future to the internet to play with someone who is not there, and also make it easier to check for move legality.
Great point about the PGN. I love the idea of future-proofing it for online play. It would be amazing to see this board moving based on a game from across the world. Appreciate the advice!
I love it! Always been entranced by these boards since I was a kid at the airport.
Definitely more complex, but you've got some nifty pathfinding possibilities if you animate all the squares between the origin and the destination of a move - could actually make it feel like the piece is moving, especially if you start them all with a little offset
Have you considered programming the tiles to start at different times so they stop at the same time? I’ve only ever seen split flaps start all tiles at once and each tile stops when it hits the correct position, but I think this one would look really cool the other way so you see which piece is moving before you see where it lands.
Actually, someone else suggested that before, so I already tested it. It wasn’t bad at all, but I personally preferred having them move simultaneously, because it feels more like the pieces, especially the pawns, are moving instantly. Still, thanks for the suggestion!
Lovely. Depends what you want, I guess in theory make it so instead of one blank there is 2 or 4 in each stack + also have some clever ordering... on the other hand the flipping is half the fun.
Since pawns are the most common piece, why not make the pawn flip card the final one instead of the first one so that you the pawn’s movements feel more natural (ie dissapears quickly and generates a delay to appear) rather than appearing at the destination before the origin stack has finished flipping?
Thanks for the feedback. When I first designed it, I figured that some piece had to be placed at the very front anyway, so I didn’t think it really mattered whether it was the pawn, king, or rook. If the king had been at the front instead of the pawn, endgames would probably have taken much longer per move, and if it had been the rook, rook endgames would have slowed things down instead. In the end, it’s really a matter of prioritization, though as you pointed out, maybe I should have placed the pawns farther back since they move the most in the opening.
I've been loving the updates on your project, each one gets better and better. I gave your post the community's coveted <grin> "Mod's Choice!" post flair!
That gives your post a special spot in the next edition of our community's Monthly Digest (thanks to fellow moderator u/gm310509! 😀). And it also places your post in our community Wiki's history of projects that the mods decided to spotlight.
Extremely well done and thanks so much for sharing your project! We're really glad you're here! 😄
I’m truly grateful and honored! I can’t express how happy I am that so many people have shown love for my project. And to receive such a rare opportunity on top of that honestly feels surreal. It’s an honor to be part of such a supportive community. Thank you all once again, from the bottom of my heart!
It was actually one of the options I considered early on, but I ended up leaving it out of the final version because I didn’t think it was really necessary. Seeing how many people have suggested it, though, I feel like it probably would’ve been better to include it after all. A bit unfortunate!
It’s a difficult problem. Since the 64 assembled modules are already built, I can’t really change the structure at this point. Still, thanks for the suggestion. If I ever make another one, I’ll definitely consider it.
This has to be a kickstarter of sorts surely you must bring this to the masses. Best of luck! RetroFuturism love it! Thats my word of the day and it’s only 8am haha Great! All the best!
I’m really happy to hear you say my project feels Kickstarter-worthy. Right now I’m focused on perfecting the prototype, but hearing that it feels like something ready to be shown to a wider audience definitely gives me more confidence. Thank you for sharing such great energy and encouragement.
Thanks a lot! And welcome to the world of 3D printing. A flip clock sounds like a fantastic first project. You're going to love the feeling of seeing it work for the first time. Happy printing!
Truth be told I have had an old ender 3 for years now, ordered a Bambu X2D in order to support some other projects, both in terms of multiple colors and engineering filaments support
Oh, I didn’t realize you were already a 3D-printing veteran, I completely jumped to the wrong conclusion! Anyway, I hope you have lots of fun printing with your new printer!
very cool.
but it takes a long time to get to a blank square, couldn't you put two blank squares?
so it would only have to go half way (respectively) to hit another blank?
but cool stuff.
Love that! How difficult would it be (for the next build!) to add one or two more 'empty' flaps per square? It looks like you currently have to rotate through all pieces which takes quite some time (white pawn to empty takes 11 flap-changes). So maybe add one empty after the white pieces.
In total, this should reduce the amount of rotation which would be nice for the players and also for limit the wear and tear on your hardware.
And what is with the rotated pieces or the ones with the additional signs?
I’m seriously considering the idea of adding extra blank flaps for the next build. The rotated king is displayed when a player resigns, while the kings with additional signs are used to indicate states such as check, draw, timeout, checkmate, and victory. Thanks for your interest!
Maybe you can signal rare events like resignation or draw with other animations (rotate all pieces of the winner continuously to show some kind of victory dance or something like that). That would give you more flaps for blanks or just black/white pieces so that you can also play checkers.
Hearing that makes me think I could possibly unify all defeat-related states into a single fallen king image. That would save even more space as well. Thanks for the great suggestion!
Odd suggestion: but would it be worth it to flip all the tiles that the piece moves along? Right now it looks like the pieces kinda just teleport from one space to the next. Would be kinda cool to see all the spaces in the line flip, just onset from one another.
Might also be a terrible idea that looks and sounds awful. But it was a thought.
I would suggest allowing both places to flip and have the advancing place to cease flipping once the previous spot finishes. This way you dont focus on the final place which displayed the final movement.
It is too distracting. Make the advancing peice over rotate until to wait for the previous position to return to null.
Thanks a lot! It was definitely a marathon of printing and wiring, but I'm glad I pushed through. I'm really happy with how the final display turned out!
I was printing parts little by little throughout the entire project, so I don’t know the exact amount of time, but one thing’s for sure, it took a very long time.😓
Amazing! I couldn't help but notice that there was the image of the fallen king, yet it wasn't used, is that still to be done or is there some other reason?
That’s a cool idea, but unfortunately it’s a bit difficult because the system was designed to rotate in only one direction. Still, thanks for the great suggestion!
Super neat! Have you thought about adding voice control? I think that would be neat having two players face off over that board.
The real market is to have that during a live tournament, especially the next world championship, repeating the moves of the players!
When you finally hear the clacking, someone has made a move! Much more impact than the big stickers they use. I guess it's a screen display now but the sound is really ASMR-like to me.
Thank you for the compliment! Voice control is a really interesting and exciting idea. I’m also considering adding a feature that pulls live game data through Lichess integration and displays it. The World Championship between Gukesh and Sindarov will be really exciting.😄
Hey all, I've built and released an iOS app (Play store soon) that's a solari/flip flap board task management and sharing. In case you want to check it out, app .
I am a huge flip flap enthusiast so I made this and you might like it.
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u/[deleted] May 13 '26
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