As noted in Tanishq Jaiswal’s write-up, “The general perception of stepper motors nowadays is the ones used in the 3D printers, that is Nema 17, but to my surprise, I came across some really weird stepper motors on one of my expeditions on AliExpress.” Such motors are available in a wide variety of sizes, some so small in fact that they can fit on the tip of your finger!
What you’ll do with something like this is left, as they say, as an exercise for the reader. With ridiculously low prices, and typically extremely long lead times, however, sometimes it’s worth ordering a few for experiments. According to Jaiswal, these mini motors require such a small amount of power that they can even be driven directly, at least in some cases, by an Arduino’s output pins.
You simply need to connect each of the four leads to an output, controlling the outputs in what amounts to a rudimentary H-bridge configuration. Software-wise, one can then use Arduino’s built-in stepper library, other available code, or even write your own. More background about how this type of motor works is found in the video below.
The biggest challenge here, or at least the most delicate part, is actually connecting the wires together, given the very small scale. The video below elaborates a bit more on how these motors are driven, and such a small stepper setup could serve as both an interesting component for a very small robot etc, but as a neat learning tool since there’s no complication of using separate drivers. On the other hand, Jaiswal doesn’t have specific current requirements for his stepper, and there are many models from which to choose, such a technique should definitely be considered experimental!