Arpeggiator

Arduino based arpeggiator for modular synthesizer.

arduino code here : https://github.com/alexiszbik/arduinoarp

2x Jack female output
1x Arduino Nano
1x MCP4725
1x 78L05 voltage regulator (for converting 12V from eurorack voltage to 5V)
14x switches
14x 10k resistors
1x 100k resistor
1x Diode 1n4148
2x 10k potentiometer (4.7 k or 100k is Ok too)

This is a first version of this project. I plan to do a second version someday, with a better circuit and more features.

There is a very interesting thread on the Look Mum No Computer forum here : https://lookmumnocomputer.discourse.group/t/arduino-arpegiator-module/2581 (Thanks to Sound Bender for posting this project in the forum).

There is few things that can be improved in the circuit :

  • Adding Schottkys diode around the clock input would protect the pin of the Arduino.
  • Also using an Op-Amp buffer at the Pitch Output will also protect the analog out of the MCP4725
  • Using a 78L05 seems to be useless cause Vin should takes a voltage between 7V and 12V. In my case, I use eurorack 12V, so it should be fine but I didn’t tested it yet!

Thanks to the people from LMNC forum for pointing out that mistakes.