Eurorack has taken over the synthesizer community, and hundreds of people are building their own eurorack modules. [Michael Forrest] designed and built his own Eurorack sequencer module that doesn’t use weird things like capacitors and chips to store a signal. Instead, he’s doing it with stepper motors and some clever engineering.
The basic idea of a Eurorack sequencer is to somehow store a series of values and play them back repeatedly. Connect that sequence to a clock, and you get the same pattern of sounds out of your synth. This can be done digitally with a circular buffer, in the analog domain with a bunch of FETs and caps, or in this case, on a piece of paper glued to a stepper motor.
The key bit of mechanism for this build is a stepper motor with 96 steps per rotation. This is important, because the module is controlled by a clock pulse … // Read more: original article.