There are wonderful oddities of synth creation breeds out there in the wild — strange, one-of-a-kind birds with three wings and forked duck-bills and other oddities. They might not all be practical for more than their creator, but like evolutionary anomalies, some adaptation or design feature might well make it into other productions – all the more reason that open schematics and permissive licenses could benefit the larger ecosystem, the rich, muddy wetland marsh of sounds.

Friend and neighbor Marc Resibois points me this week to the Fatduino. It’s pertinent to our discussion of marriages between DIY synths and the open source Arduino prototyping platform. Specs:

  • Paia Fatman analog synth (described by the creator here as “a digitally-controlled analog monophonic synth kit. It has 2 sawtooth oscillators, a resonant filter, ADSR for amplitude and ASR for filter cutoff.”)
  • Arduino MEGA as controller.
  • Synth + step sequencer + arp + software LFO.

Here’s the idea: the Fatman already has a controller that receives MIDI notes, and uses those as digital control of the analog oscillators fine and coarse tuning (and envelope generators). In this project, the Arduino cleverly substitutes for that controller for easier programmability and inputs.

Upshot: you get arpeggiator and step sequencer modes, and, for those wanting to program, the cozy confines of the Arduino environment.

There’s also a new, software-based, routable LFO.

Full details and schematics and code are available on the site. Bless you, garage Scottish engineering, and Nibbler Nibbles:

This wouldn’t be a bad starting point for other projects interfacing digital control with an analog synth for more convenience. And you get some tasty-sounding results, as in the videos.

On the MeeBlip project, we’ve had a number of conversations about interfacing with the Arduino. They come down to this: the Arduino is most useful in musical purposes as an interface for controls, sequencing, and MIDI. Now, you don’t actually need much in the way of interfacing for most projects. Because the MeeBlip is already a digital project, you don’t really even need a “shield” as such – you can just connect serial or MIDI directly into the synth. By contrast, trying to implement a synth on the Arduino’s fixed hardware and firmware isn’t necessarily satisfying.

But I’ll defend the Arduino for simple sequence timing and control input; on these tasks, it’s pretty straightforward for a hobbyist.

The previous example:
SJS-ONE: Open, Arduino-Based Synth, with Crazy Cases and Web Troubleshooting

I’m interested to see if anyone builds on this kind of project.