It's three 555 oscillators a 1M pot each for for the osc rate and then three 100K pots that control the way the oscillators affect each other. I drilled sereval different size holes for the speaker on the right hand side. I pulled apart a cup that was designed to hold pens to make a screen for the speaker. I'm really happy with the whole aesthetic of it. There is also a LM386 chip in there too. It helps make it nice and loud.
I used 10k resistors from pin 7 to pin 8 on each of the three 555. The capacitors I used were .022uf, .22uf, and 2.2uf. The first two values were mylar caps and the last one was electrolytic.
I used a 1k pot for the voltage starve pot on the left hand side. Originally I was just hoping it would work as sort of a volume knob, but it ended up adding a cool distortion effect as well.
When I first added the three 100k pots, I just intended them to just kind of affect the pitch in a different way by varying the resistance from pin 7 to pin 8. I also didn't put the diodes in between the three different outputs from each 555 at first either. After I was running it for awhile I noticed the chips all got crazy hot. The oscillators started feeding back into each other and i was lucky they didn't melt. So I added the diodes and added fixed resistors in between pin 7 and pin 8. I found out that the three 100k pots now affected the way the oscillators mixed with each other. Here is a very basic diagram of how the pots work.
Here is a video of it in action...
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