[HN Gopher] Pi Chess Board
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Pi Chess Board
Author : GordonS
Score : 129 points
Date : 2024-11-10 18:40 UTC (4 hours ago)
(HTM) web link (readymag.website)
(TXT) w3m dump (readymag.website)
| johtso wrote:
| Not sure if I missed it, but I didn't see any mention of how
| player moves are detected. Is there a camera and CV? It's always
| seemed like a fiddly problem to solve with electronics as you end
| up needing a matrix of sensors so there's a lot of wiring.
| stevenpetryk wrote:
| I've always wanted to try making a smart chess board (with no
| moving parts; merely detecting moves rather than making them).
|
| I've thought of:
|
| - RFID. Have 64 antennas and multiplex them to detect which
| piece is on which square (idk much about RF so this felt tough)
|
| - Vision with a fiduciary mark under each piece, and an acrylic
| board
|
| - Hall effect sensors, where instead of knowing which piece is
| which, it instead assumes the normal starting position and pays
| attention to which square was picked up from and which square
| was placed onto to infer which piece moved.
|
| I think with any of these approaches it'd be fun to make a
| tiny, single-PCB board.
| moffkalast wrote:
| Yeah there are some trainer chess boards that use hall
| sensors to track piece movements. But I think there is a
| possibility to actually encode pieces with different magnetic
| field strengths and flip them for each player. That way you
| can just do stateless reads and you'll always get the correct
| readout, plus you can recover from illegal states.
|
| I did a project [0] a few years back that did this absolute
| encoding for senet, since there is only one type of figure
| and two players so just flipping the magnetic field worked
| really well once calibrated. I still need to make a proper
| writeup/video on that thing one day...
|
| [0] https://imgur.com/a/a29CTXl
| awfulneutral wrote:
| I was trying to do something like this a while back, our
| approach was to have a different color underneath each piece,
| with an elaborate setup to get the colors reflected into a
| camera, but I could never get the color detection working
| reliably with the way we were doing it. It was a fun project
| though, there's got to be some easy way to detect moves and
| get a cheap-ish internet-enabled board.
| dmurray wrote:
| > RFID. Have 64 antennas and multiplex them to detect which
| piece is on which square (idk much about RF so this felt
| tough)
|
| The professional-level boards by DGT use RFID and retail for
| about $500.
|
| I looked into building a competitor some time ago. 64 RFID
| antennas alone would have eaten up that budget. I believe
| they do something smarter like having 8 antennas and
| arbitrating the signals. They have some patents in this area.
|
| I've seen Hall effect and barcode-based systems too. They've
| always been a bit less reliable than DGT. Actually DGT is not
| all that reliable: if you are broadcasting a 20-player
| tournament you will need to manually update the broadcast
| around once per round. However I think the position detecting
| (hardware side) is solid and they could do with improving the
| move detection in software.
|
| None of this is meant to deter you from building this as a
| hobby project! I think all the approaches would be fun to
| try.
| thrtythreeforty wrote:
| DGT uses a (patented, expired [1]) resonant LC circuit, not
| RFID.
|
| [1]: https://patents.google.com/patent/US6168158B1/en
| tzs wrote:
| Put an ultrasonic emitter and an accelerometer in each piece.
| When a piece completes a move emit an ultrasonic pulse
| pattern unique to the piece. Pick that up with 3 ultrasonic
| microphones places around the board and use the time
| differences between when the pulses arrive at the 3
| microphones to find the location of the piece.
|
| Maybe use 6 different frequencies (one for the white King,
| one for white pawns, and one for the rest of white, and
| similar for black) to make it easier to handle moves that
| affect more than one piece.
|
| The moves that involve more than one piece are captures (one
| piece of each color), castling (one King and one Rook), and
| pawn promotion (one pawn, one piece of the same color that
| the pawn promotes to, and possibly one piece of the opposite
| color if the pawn captures during the promotion).
| programjames wrote:
| > Functionality and Features
|
| > The Pi Board is an advanced automated chess system powered by a
| Raspberry Pi, utilizing an XY stepper motor mechanism and magnets
| to move chess pieces seamlessly across the board. The development
| process involved several key stages, including precise
| calibration of stepper motor coordinates, calculating the weight
| of each piece for accurate handling, integrating a robust chess
| engine, and optimizing piece-grabbing strategies and movement
| detection. Special attention was given to selecting the most
| efficient algorithm to minimize the stepper motors' power
| consumption.
|
| Is there a reason for the marketing speech? I'm assuming most
| people interested in this would rather read engineering speech,
| like so:
|
| > The Pi Board, as the name suggests, uses a Raspberry Pi under
| the hood to calculate engine moves from <Stockfish? Leela Zero?>,
| and move the pieces with a series of stepper motors and magnets.
| We spent a significant amount of effort minimizing power
| consumption, including weighing the individual pieces to get more
| efficient grabbing and moving motions for each one.
| jstanley wrote:
| Probably an LLM-assisted blog post.
| jihadjihad wrote:
| Yeah it really does read like something spat out by ChatGPT.
| They always have to include the word "key" for some reason.
| dankwizard wrote:
| I wish they added some LLM-assisted CSS & Div tags because
| this layout is atrocious.
| metal_am wrote:
| It must be. The part about minimizing the stepper motor power
| consumption is nonsensical. Steppers use the same current
| whether moving or stationary.
| alexfromapex wrote:
| Truly a mechanical turk
| ramon156 wrote:
| Really cool!
|
| Side note: there are some typos in the last header :P
| dr_kiszonka wrote:
| Maybe slimmer pieces would help prevent collisions during
| movement? (It is a pretty obvious suggestion, so likely there is
| a reason the author didn't take this approach. Is the lower bound
| of the piece's base determined by electromagnet strength?)
| beardyw wrote:
| The pieces look to be well below normal size for that board. At
| normal size it would be very difficult.
| bitwize wrote:
| The fact that we have tinkerers building their own working
| versions of a well-known 1980s Brookstone novelty gadget makes me
| smile. Reminds me of the guys who built their own Segways back
| when we thought Segways were things people actually wanted.
| vunderba wrote:
| I've seen these kinds of chessboard automaton systems before, and
| they commonly struggle with complex movements, such as castling
| pieces, capturing, and the movement of knights.
|
| A lot of them can't handle "contingent movements" where you need
| to displace piece X but in order to do so, you first have to
| displace piece Y, and then rewind the stack to restore the
| original pieces positions.
|
| The second video where they demonstrate the actual gameplay
| footage exhibits some of these problems with this board, e.g.
| pieces that are displaced don't seem to re-center automatically,
| etc.
| btbuildem wrote:
| Interesting approach! I like how moves with pieces in the way
| were solved for the most part. A bit disappointing that the taken
| pieces have to be manually removed -- one way to handle that
| could have been to extend the range of the "head" to the margin
| of the board, and have it drag off the captured piece to that
| area before moving the capturing piece there.
|
| I wonder if another mechanism altogether could work a bit better
| -- a matrix of electromagnets embedded under the board, with a
| resolution of say 1/4", so that when deployed in sequence, they
| could move the pieces from one magnetic field to another and
| another, without any actual moving parts involved.
| CrazyStat wrote:
| > I wonder if another mechanism altogether could work a bit
| better -- a matrix of electromagnets embedded under the board,
| with a resolution of say 1/4", so that when deployed in
| sequence, they could move the pieces from one magnetic field to
| another and another, without any actual moving parts involved.
|
| A standard chessboard has squares of 2-2.5", so this would
| require at least 4096 electromagnets.
|
| There was a kickstarter [1] for such a design a couple years
| ago. The conclusion in the chess community was that the
| kickstarter was a fraud [2] (with faked videos) and such a
| board would not be commercially feasible.
|
| [1] https://www.kickstarter.com/projects/soontech/regium-
| automat...
|
| [2] https://lichess.org/@/lichess/blog/regium-extraordinary-
| clai...
| gizajob wrote:
| Hate to be a spoil sport but if when pieces move they nudge other
| pieces out of the way and then those nudged pieces have to be put
| back by hand, then there's still work left to be done. Same goes
| for capturing - the captured piece should walk itself off the
| board.
| ekianjo wrote:
| Yeah the videos were far from impressive...
| jtxt wrote:
| Cool project!
|
| Could a hefty reverse magnetic pulse launch captured pieces off
| the board? And maybe with some precision by controlling the
| offset and power?
| omoikane wrote:
| I watched through all of that game play footage just to see if a
| castle would happen, and it did happen at the end, with the same
| bumpy movement that ran throughout the game.
|
| The most interesting bit was probably near 1:50 where the pawn
| moved sideways.
| MarcelOlsz wrote:
| >the pawn moved sideways
|
| Holy hell!
| GianFabien wrote:
| So if there are challenges in moving the pieces from below, then
| why not have a robotic arm that reaches down and grabs and moves
| pieces? A bit of computer vision might help with accuracy.
| realslimjd wrote:
| Because that's even harder.
| lambdaone wrote:
| It really, really struggles to move the pieces. More development
| is needed.
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