You make a move on your board and the system wirelessly transmits the info for the corresponding to move to take place on your opponent's board. They make a move, and you see the piece move on your own board...
FunGowRightNow12' frameborder='0' allowfullscreen> has documented the Wireless Arduino Powered Chess project on YouTube:
Our goal is to allow people to connect and play board games with each other from anywhere in the world. By combing a physical board with modern technology, we hope to bring a more interpersonal experience that is not achieved through a computer screen. See our other videos for a look inside the system and how moves such as castling and en passant are handled.
A view of the device's insides:
But chess isn't draughts, there are lots of weird and wonderful moves and exceptions (en passant, castling, illegal moves). How are these handled?
Time to see the system in full, game glory: (I like it when a taken piece makes its own humble way to the sidelines, on the remote board!)
You know, it kinda reminds me of Ol' El Ajedrecista ("The Chess player") - see El Ajedrecista, the first (chess playing) computer game