This is a four button USB MIDI controller, plug and play ready to start making beats at any time. It features Sparkfun's 2x2 LED friendly button pads and PCB, an ATMega328P for the main logic, 74HC595 for controlling the 4 RGB LEDs, and a laser cut enclosure.
Made possible by today's healthy distributed digital economy:
* pads and pad PCBs from Sparkfun
* other parts from Digikey
* logic PCBs fabricated by OSHPark
* wood box laser cut by Ponoko
I've uploaded the Eagle PCB files (now with the correct pull-down resistors), OpenSCAD files for the box (and a ready-to-laser SVG export), and the AVR C firmware for the ATMega328, all to Github for your cloning pleasure: https://github.com/spro/megamidi
The PCBs arrived from OSHPark and came out perfectly to spec, as usual. The only issue was my own oversight, forgetting the pull-down resistors for the button pads. The solution was easy enough: