Hey all, I'm pretty far along on an arduino-based MIDI arpeggiator. You run a midi controller into this widget, then run a midi cable from the arpeggiator to the tone source of your choice, and when you play a chord it will be arpeggiated. Rate is adjustable with a knob, as is tone length (i.e. how long after a "note on" is sent is the "note off" sent). Toggles for direction, range, hold, and whether notes are arranged in chromatic order or in the order played — this last setting combined with hold means you can make up your own arpeggiation patterns. There's also a PANIC button that sends an All Notes Off, for when a note ends up stuck on. I'll be posting the code etc when it's finished, or at least a little closer to finished. Still to come: syncing to a trigger (e.g. footpedal, audio line), syncing to a midi clock (i may not deal with this one), and last but not least:
How should I turn the thing off? Or more precisely, what should the ON/OFF button do? As far as I can think, I have two options:
- The OFF position has the micro just forward MIDI events as they are received without arpeggiating notes.
- The OFF position electrically disconnects the MIDI out port from the micro, and instead connects it to the input port (ideally using a MIDI thru amp circuit).
The first option isn't ideal because the midi library I'm using (understandably) doesn't have a "forward" function, so I think I'd need to write individual little handlers that I skipped for the arpeggiator (e.g. "when a program change is received do x", "when a pitch bend message is received do y", etc etc). That seems like a pain, and although they'd be minuscule, it'd add latency. On the other hand, I should arguably be forwarding messages other than note on/off anyway, and this way you could switch off the arpeggiator while it's playing without worrying about creating a stuck note.
The second option skips the hassle and latency involved in me writing an arduino middle man, but you could easily end up with a stuck note if you flip the switch at a bad time. Just swapping a midi electrical connection also feels a little "wrong" to me, but I don't have a specific reason why (bad for the opto on the other end, maybe).
Any thoughts? Am I overlooking a convenient third option? Or being an idiot worrying about the downside of one of the above two?
