Working on the sequencer. It uses a 4017 decimal counter, and, at least for this test, an Arduino as clock source, because I couldn’t get my 555 circuit to work.
Ran the output of the sequencer into one of the analog inputs of the Auduino synth, which made for some funny noises. Also connected the synth to the newer oscilloscope. Great stuff.
Finally, I managed to build a filter stage for the synth to clean up the PWM output signal (which you can now see on the scope). Turned out pretty much as I hoped it would. Circuits etc. will come later.