I have a Midibox SID with a basic control surface. Using the knob to select random patches is not the best when you are trying to pick a specific patch, or a higher numbered patch.
In performance, there are generally lighting problems and these displays can be hard to read. Being able to enter a patch number via a keypad would be more efficient. A display would be nice, but not necessary. I may look at the C64 8x8 keyboard encoder to see if I can make that work. The software would then have to be changed to accept input from the keypad.
There should be a way to do this as a Midibox module which could plug into the DIN/DOUT bus rather than MIDI. That would avoid the requirement for a MIDI merger.
Update : Just found some 16 button keypads in my parts box. They are wired as individual switches with a common ground. Keys are 0-9, A, B, C, D, # and *. I could just connect this keypad to a DIN module, then I would just need software to make it work. Pointers on how to do this would be appreciated.
--tom