Yes exactly, I thought that if they work as any potentiometer it should work. Actually I wasn’t thinking of mixing the signals back into the synth, but perhaps control on/off or volume of an external source with the ribbon or a button, through the Arduino. I’m not sure about the exact level.
If I mix it into the synth I guess I should shift the level as you say. How would you do it with an op-amp, is there an example somewhere?
I found this Arduino project that seems to do this wth just some resistors and some capacitors, but I haven’t tried it myself. But I guess it should be the same for the Nanosynth, perhaps?