I wanted to make something cool while challenging my proficiency with Arduino and building electromechanical systems. I was interested in using magnets to do something to make it appear magical so I basically set out to make the 'Wizard's Chess' game from the Harry Potter series. Game is between two people sharing the computer; the computer isn't the second player unfortunately...yet.
Featured as a Top Project in the December 2018 issue of HackSpace Magazine (https://hackspace.raspberrypi.org/)
The board is hooked up to a computer and requires the player to input a square address of the piece to be moved and the new location for the piece. The electromagnet is moved by two stepper motors and timing belts. Each piece has a loose steel ball bearing inside to allow them to easily slide around.
The biggest problem I had was getting the vertical axis to move smoothly without catching and missing steps. It doesn't happen often but when it does I just had to close the serial monitor and reopen it which reset the Arduino and zeroed the magnet position.
Pieces are initially offset to the corner and moved along the lines between squares to avoid colliding with other pieces.