From the MAKE: Flickr pool
Spikenzie Labs’ impressive Button64 project offers a whole lotta input for Arduino/etc –
Decoding a button press is done with the help of a MCP23S17 port expander from Microchip. This chip has 16 general purpose I/O pins (GPIOs). Eight I/Os are used for the columns and other eight for the rows, forming a 64 button matrix. The columns (port B of the MCP23S17) are set-up as outputs and the rows (port A) inputs.
One of the great features of this project is that there are no diodes! Unlike many button matrices, itâ€™s just the buttons and the MCP23S17.
Great aesthetics for such a useful device. It’d likely be a great interface for Arduino-Bingo ;)
Thoroughly detailed description of how it all come together in software/hardware over there – Project 64 / 64 Buttons
1.5 hours of wiring â€¦