PCB Stepper Motor Micro Robots

[Kevin Lynagh] is interested in tiny PCB stepper motors, and after reviewing the various projects and patents to-date, decided to give it a try himself. These are basically a stepper motor that’s been unrolled and made flat — traces on the PCB act as the coils and tiny magnetic “robots” act as the rotor.

If you want to try this concept yourself, [Kevin]’s post contains an excellent survey of prior art and projects, as well as exploring the theory behind how these things work. He has taken a deep dive in to the theory, deep enough to grasp what’s going on and to build some preliminary prototypes with a bit of confidence. First off was just a hand-wound flat coil as a proof-of-concept. Next was a PCB version that worked almost exactly as planned, although he confesses to burning out a motor driver circuit before stepping back and making some calculations.

We covered one such project back in 2014 and wrote about a Hackaday.io magnetic robot project from reader [bobricius] in 2018. Have you ever used this technology for anything besides a demonstration? Let us know in the comments below.

Thanks to [Adrian] for sending us the tip.

The Two-Dimensional Stepper Motor

Over on hackaday.io and deep in the Hackaday Prize, a lot of cool people are playing around with the possibilities of putting coils in printed circuit boards. On the face of it, it makes sense: drawing spirals on a PCB gets you an electromagnet. This allows you to do all sorts of crazy things. You can make miniature model maglev trains using the track as a motor. Someone built a wearable Tesla coil.

The latest build to show off the possibilities of motors etched on PCBs is [bobricius]’ micro manipulator. It’s a 100 mm square board capable of moving a small magnet around the surface. The point? Well, if you have to ask that question you’re really never going to get the point.

The design of this stepper motor is simply two coils of wire, with the X axis of the grid placed on the top copper layer of the PCB and the Y axis on the bottom copper layer. There are four poles to each of these coils, and they plug right into a standard stepper driver, so to control this board all you need is a basic Arduino and a motor shield. Or a RepRap board, take your pick, you probably have something sitting around in a junk drawer.

In the test of this board, the stepper motor can move small rare earth magnets around quickly and with high repeatability. As for what use this PCB stepper motor has, if you have to ask that question, you’ll never know. Also, because it looks cool.

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