I am using a Teensy 3.2 and associated Audio Shield to fully digitize the internals of the Otamatone, which was previously an analog synthesizer. Build log and source code will be featured here. Always open to any suggestions for improvement. Better formatting to come!
ah this is exciting to hear! I took apart my Deluxe a few months ago and contemplated a similar project (add Teensy-based synth). Never followed through with it, so I'll be sure to watch this one. good luck!