The cheater's chessboardSun Jan 03 2021
The idea is to build a custom chessboard that looks like a regular chessboard (with maybe clock at the side for time games) but can actually read the state of the board, calculate the best move, and secretly leak information about the best move to a player in the know.
How we'd do it
We'd have to wire up a Hall effect sensor for each square. A Hall effect sensor is like a reed switch which can detect the presence of a magnetic field.
The idea is that when the piece is lifted up, the circuit will cut off (0) amd when the piece is put down, the circuit will close again (1).
We won't be able to distinguish between pieces, but we will be able to guess it by assuming that the board is set up in the correct position at the start.
So for example if we detect that e2 square cuts off, then shortly after e4 square cuts on, it's most probably e2e4 move. We will have to handle things like castling, en passant, promotion (especially hard because a pawn can promote to any piece).
We would then feed this board state to a Raspi mounted within the chessboard, which would use a chess engine to calculate the best move and leak information to the player in a surreptitious way.
How do we leak information?
We need to leak information in a sneaky way Basically if you think about it we need to leak 12 bits: 6 bits starting square and 6 bits ending square uniquely determine any move (except pawn promotion, but we can worry about that later). For castling you can talk about the position of the King (moving two or three squares).
My idea is that we have clocks on either side of the board which act as time controls, but they will leak the information somehow, either by a different border thickness/ brightness level/something else.