I2C Game Controller for Arduino / Raspberry Pi

As part of my LED-Matrix Table project (https://github.com/rottaca/LEDTableEngine/wiki) , I designed this game controller to control the table and to play games. It can be used as an input device for a wide variety of micro-controllers or raspberry pi computers.
Up to 8 controller can be used in parallel with the same control chip. The state of the eight buttons can be read by using the I2C protocol and therefore it only requires 4 wires for connection.

The setup instructions can be found