[...] I&#8217;ve been working on a step sequencer design for a while based on the 4017 decade counter. I&#8217;ve finally gotten around to building a working prototype! I posted the schematics here a few months ago. You can also find them on the step sequencer page which I just uploaded.  I also uploaded an awesome recording of the sequencer in action. The recording was made using the sequencer to trigger three different synths. A casio SK1 was used to make the melodic sounds.  I used a Korg MS20 to make the bass drum beat. The other rhythmic tones were made with a Paia modular synth The casio has been modified to allow an external trigger to activate the recorded melody play back feature. So I can record a melody into the SK1 and play it back one note at a time every time i send a pulse to the new &#8220;playback&#8221; jack. Here&#8217;s the step sequencer page. [...]