Do you remember that I have asked you such a project a week or so ago, to do FM modulation aka adding vibrato to the oscillator bits ?
Of course, you can modulate the VCO at the input, but there is no way to keep tune tracking correctly and to modulate the signal.
By now, I found two ways to work it out, using the arduino or to modulate the VCO, or to make yourself a bit module, which can combine the modulation wave and the tune input.
For such, we certainly need a sone wave. The arduino can generate a sine PWM or we can use brute LFO.
More of this will certainly follow shortly in this forum, and we can compare the circuits all together and make combinations
BTW, did you check out the string synthesiser that I’ve made possible into the littlebits environment ?
And oh, @alexpikkert, how did you manage to tighten the spin disc on the fan ?