Wow. This is one of best DIY thing I've seen. Bruce Murphy built this kind midi controller for his Clavia Nord Modular G2 Engine. Into his site he explain features and how he built it.
From his site:
"The LCD panel displays patch numbers and names, The knob is an endless rotary encoder used to dial up a patch, the keypad allows a number to be typed in directly, and the buttons on the right control mode, patch loading etc. LEDs display communication status with the G2, MIDI busy, and so on.
Current features:
- Query current patch by slot
- Dial/Enter patch number, buttons to switch banks
- Query name of patch by bank/number
- Load patch into synth"
