Hope you all are safe and healthy. Recently, I been working with some projects on microtonal music. Projects like PreenFM2 & H-Pi TBX2b inspired me to a great extent, it would be fascinating in case we could replicate or create a DIY project similar to those with the bare-bones minimum using Arduino or teensy. In my scenario, scala files will be stored in an external MicroSD card as cent values, then it will be read and pre-processed in poly mode from 1-16 MIDI channels separately into arduino. Obviously, the deal here is to convert cents to pitchbend values and perhaps maybe we might also need to create a separate library for that purpose. By random on Google search, I came across a thread with the title "polyphonic microtonal converter using arduino" but that thread is no more active now. Someone, should you are familiar with this topic can shed some light.
Given that a pitch bend gives you a predictable shift it should be a simple matter to calculate how many you need to add to each note to achieve the not you want. Are you looking for half or quarter note intervals?
The amount of shift a cent gives you is also related to the master control of the pitch bend, so that might need to be set as well.
I have listened to some microtonal music and I find it difficult to spot if the interval is too fine.
I have a friend who did a similar thing, I will ask him if he made it open source, he normally does.
I have managed to pull things together for my Teensy Micro Tuner… though it’s taken some effort to track down working versions of the Arduino sketches.
I need to test these actually work before I upload them to GitHub and post to my blog, but I don’t want to inadvertently brick my working device - so I’ve ordered some of the components I need and will build another breadboard prototype to test the code.