What do I need to know when choosing the right optocoupler for a MIDI input?
There are a bunch of schematics on the internet for midi input using the 4N25, 4N28, 6N137 like in the shruthi, 6N138, etc. I have been reading up as much as I can, but still don’t understand why or if one type would be better suited for midi input. Or how to calibrate my circuit with the optocoupler for the best performance.
Also, I did make this circuit here at “instructables”:http://www.instructables.com/id/Arduino-MIDI-in-shield/
Although I got it to work, the midi data bytes were not accurate coming through the optocoupler on the serial monitor, even though they were in typical 3 byte midi groups.
Any help would be greatly appreciated. Thanks!