Before I begin, I must say that I am very poor in programming and especially so in Python. I am pretty good at hardware so I doubt that how I have wired my circuit is the issue (though I cannot rule it out). I am here because I am doing a final project for a microprocessors class and can't seem to get it to work.
The Problem:
I have assembled a very simple version of the SamplerBox with only a Raspberry Pi 3, SD card reader, USB DAC, 6N138 optocoupler, and brand new USB (a Cruzer Blade, if that matters) for samples. My ultimate goal is to only play one set of ten samples; no other sets and no more than ten samples (Maybe there is some simplified code I could use instead?). I downloaded all three image files I could find and currently have the 2016 version on my SD card. My sample-set is in a folder named as suggested in the FAQ (i.e., number-space-name) with samples named by their MIDI notes. I guess I should also note that I made my own MIDI controller using the Arduino MEGA.
Troubleshooting:
I first figured I must have shorted out something in the circuit, so I tested many points and they all seemed to be receiving the right amount of voltage and current. Seeing that there was nothing wrong with the physical components, I figured I might as well check the code. I first checked the Arduino code and there seemed to be nothing wrong with it. Therefore, my suspicion is that it has something to do with the Python code. I have tried changing some lines in the config.ini file, but I'm not really sure if I'm doing it right. One thing I did notice, however, is that none of the image files I downloaded have the default "Saw" folder. In fact I did not see any sample folders whatsoever. This may be normal of course, because I honestly have no clue what most of the files are for anyway.