8 step DIY sequencer for your DIY synthesizer or a VCO

8 step DIY sequencer for your DIY synthesizer or a VCO.
This is a very simple sequencer based on just 2 inexpensive chips and 8 potentiometers.
Very cheap and easy to build!

I've added a DIU vactrol to the synth, to control it from the sequencer.
Home made vactrol is AKA a resistive optocoupler.
It consists of an LED and a photo resistor, placed in a small tube in such a way, that LED is right in front of photo sensitive layer of a photo resistor. And it's in a tube, so that external light would not mess with the pitch of the synth.

Schematics:
https://drive.google.com/drive/u/0/folders/1xMaCq6nPapXQNU68TiEYdGeQF4CrSTsD