MIDI 4+1

MIDI to 4x CV/gate, with polyphonic and monophonic voice allocation modes

A DIY Arduino-powered MIDI to 4x CV/gate interface in 6 HP, with both polyphonic and monophonic voice allocation modes.

• Single MIDI input via DIN or TRS Type A (now the MIDI standard).
• Four 1V/oct CV/gate outputs with gate LEDs.
• Button for cycling through four different modes, with coloured mode LED:
  • Poly (red): four-voices polyphony with priority to last, LRU strategy and voice stealing;
  • Poly-first (green): four-voices polyphony with priority to first and first-available strategy;
  • Split poly+mono (blue): split keyboard with three-voices polyphony on the left, and monophony on the right (priority to last);
  • Split mono+poly (pink): same as above, but flipped;
  • Mono (teal): four independent monophonic allocators, one for each MIDI channel 1 to 4.
• Additional output which can work as one of the following:
  • Gate output that stays high while at least one polyphonic voice is active (logic OR), useful for single-filter setups;
  • Trigger output for MIDI clock, with customizable PPQ (can be enabled in code).
• Voices lock with a long-press of the mode button: all gates of currently held polyphonic voices stay high, ignoring key releases until next reallocation.

The code is open-source, and can be customized with the Arduino on the back.

https://www.tindie.com/products/joeseggiola/midi-41-a-4x-cvgate-interface-pcb-panel/