Arduino based 4-voice multi-timbral mini MIDI synthesizer.
Based on dzlonline/the_synth, "Arduino synth V4.1 Dzl/Illutron 2014", see the source code. There's multiple enhancements over the original one like low-pass filter and possibility to save and load all settings (patch).
To build just open with Arduino IDE, choose Arduino pro mini 16MHz and build!
The code needs Arduino MIDI and EEPROM libraries and also my simple lib for TDI1400, that you can find from my github repo.