I am planning out a wedding present for my brother and his fiancé. I was thinking of making a 64 element (8x8) RGB chess board, with a diffused glass top. The LED would change the cell colour based on the chess piece on top of the cell. An example might be that under all the black pieces would be a red glow, and under the white pieces might be a blue glow. I have given thought that I could just have two sets of LEDs and two sets of switches turning on the appropriate colour but it still I would like to have the options that using a microcontroller presents.
I am trying to consider all the ways a person could detect the presence of the chess pieces. My problem is that, while capacitance and IR could be used to show something is on the chess board, it can’t show the colour of the piece (black or white). I am considering Hall Effect sensors using North and South Pole magnets in the base of the chess pieces. I have found several Hall Effect sensors which will produce a voltage depending on magnet polarity but the idea of needing 64 ADC is a bit scary. I know MAXIM makes 16 inputs 12bit ADC with SPI interface but even then I would still need four chips.
I suppose what I am asking here is 1) does anyone have any other ideas for a way to detect which piece is on the glass and 2) does anyone know of a hall effect sensor that detects north and south polarity but expresses it with two separate outputs. I was thinking that might be easier to multiplex digital signals then convert 64 analog signals.