Arduino Nano based MIDI to CV and DCO

I have programmed an arduino nano as a MIDI to CV with the following DAC channels (requires 2 external MCP4922 DACs)

1v/octave CV
DCO Offset CV
MIDI Modulation Wheel
Pitch Bend

There is also a square wave out at the exact note frequency to create a digitally controlled oscillator.

 

A note on pitch bend

The VCO pitch bend is via a DAC that is set at 1 volt and the pitch bend raises and lowers this voltage, so you would add this to the tune CV, tune your VCO with the 1 volt then the pitch bend would raise and lower the frequency.

The DCO manipulates the timer frequency. This is more difficult as it is a digital control without the smoothness of analog, the current design doesn’t ‘set’ the next played note to a bent value, a future version will fix this.

Also the pitch bends are not syncronised, so if you use this chip for a DCO/VCO dual oscillator be wary of the pitch bend being out of frequency. I’ve not tried it, maybe it will give a cool sound!

All files are available here

https://github.com/RHElectronics/Arduino-VCO-DCO