This design has since evolved into the Auto-Step Synthesizer which is built with the same circuit.
This is based on a stepped-tone generator. What makes it different is the built-in sweeping LFO that gives it an almost automated effect. As well as a low-pass filter that allows you to sweep the high-end in or out.
You have controls for LFO speed, frequency, pulse length, lo-pass filter, and volume. The case is an old repurposed wooden box and some salvaged parts were used.
With a 1/4″ output jack it is easy to connect to amps, effects or recording equipment. It is powered by either an included U.S. wall adapter or an also included 9volt battery.