(noob question) how to make a midi retrofit with arduino

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1

Hello, I dont know if its possible to make an arduino midi retrofit kit

Because I have an old Casio PT-88 and I want to add the MIDI IN (specially this one to use it a sound module) and MIDI OUT (for use it a controller, not so important function as a MIDI IN, because I really love the Casiotone 85 sounds), so the thing is that I want to use mi casio (as a MIDI sound module, RX PIN) to play jazzy harmonies (4 or five notes for chord polyphony minimum) with my MIDI controller plugged into it, and somethimes use it as a micro controller (but this function is less important (TX pin, MIDI OUT)

the casio pt-80 victim candidate of the midi surgery uses a "OKI JAPAN m6251-02 172019" microprocessor for sound engine (PCM lofi wavetable data), pseudo sequencing (the infamous CASIO ROM CASSETTES uses EEPPROM that its very similar to the midi function)

thanks in advance, greetings from Mexico

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    USBMIDIHost by Yuuichi Akagawa
2

I dont know if its possible to make an arduino midi retrofit kit

It probably is possible but it will not be easy.

At first glance it looks like you will need to wire an Arduino output ( or two ) to every key so the code can simulate pushing a key.
As the keys are probably being scanned in a matrix then the Arduino would need to control an analogue switch to short out the matrix scan just like the key does. That is a lot of wires and a lot of analogue switches.

If you can get a schematic or look at the signals with an oscilloscope then you might be able to simplify this method.

Then you need to simulate the velocity sensitivity of the generator. This is normally acheaved by timing the diferance between a keyboard switch being open when it is first pressed to it been closed at the end of the travel. This would involve using two analogue switches per key.

So while I am sure it could be done it is not a beginner’s project.