Basically, the ATTINY is pretty cool. I love making small one evening circuits that I can put on a breadboard, sample a bit and tear it down when I'm done.
For this project, you really just need the ability to program attiny chips, a bread board, wires, pots, leds and perhaps a few ways to HEAR the sound. I can touch on a few of those, but really, I will post links for that.
From there, just mix and match components like you would a modular synth.
I have created a few "convenience" tools, but really, I just tend to get an idea and throw it at the breadboard.
Here are some samples:
ACS-85-0210 is a delay like vco. Really, it puts the pot values in a buffer You can adjust the spread.
## Similar works
MiniMoSynthA Formfactor and open source/open hardware design to make ATTiny Blocks. Certainly the closest to what I have here. I do not really have a
consistant strategy nor a consistant input like these little
blocks. Check em out.
Rad-fi System from Bleep Labs Uses Arduinos as building blocks for Synths on a breadboard. A collection of ATTiny micros with these sketches would be completely compatible with this system.
Bastl Kastle uses 2 ATTiny85s that can be programmed with other features.
Electric Druid has some AVRs and others as building blocks. For example, an LFO.
Moffenzeefmodularhas a project called MSG. One of these sketches has made its way into that. Neat! If your not solder/hardware inclined, just get this and stick that that form factor. Looks solid, if its not sold out.