- A circuit to act as USB host, most likely USB_Host_Shield_2.0?
- A microcontroller to load firmware, most likely a Teensy++ 2.0
- Voltage regulator for Teensy to drop to 3.3V
- Some kind of project box enclosure
- Recognize an attached USB MIDI device.
- Implement the Monome serial protocol
- Translate MIDI Note On/Off and CC delta (encoder) to the Monome serial protocol
- Translate Monome serial protocol to MIDI Note On/Off and MIDI CC if there's an LED ring
- USB mini device port to connect to host and send Monome serial