I took an undocumented project from a friend of mine (DJ Soulmachine) who happily supplied his code for a mellotron digital clone from 6 years earlier. Looking at the code and his photos I was able to build my version of his Psylotron project.
https://www.djsoulmachine.com/farbeyondperception/index.html
It uses an Arduino nano (I used an Uno clone) and a wav trigger board for sound generation. A simple low pass filter is on the output to give some tone variation.
I modded the code to double the amount of stored samples from 20 to 40 available as the new updated firmware of the wav trigger allows for 4096 samples to be loaded instead of the earlier 2048. The samples must be stereo with no metadata.
Plenty of mellotron samples around on the net to download or you could create your own banks.
GitHub link
