These Two Small Steppers Are One Giant Leap for Maker-kind!

Even if you know what you're looking for, finding what you need on AliExpress can be hit-and-miss. You've got to think of a wide range of sometimes sensible, but often nonsensical search terms that might represent your desired components. A lot of it is down to translation, some of it... Well, we just don't know.

If you don't know what you're looking for, you can end regaining consciousness some many hours later, with a shopping cart full of weird and wonderful parts that you'd never have found in even the most wide-ranging surplus house stockpile!

You could fill a Venti cup with the most diverse collection of beautifully machined, high-spec DC, brushless or stepper motors, gear sets and drivers, and still pay less than you would have to have filled that cup with coffee!

Some of my recent finds below can be seen, both brushless out and in runner motors, an all-metal DC geared part, and a tiny coreless motor with a nylon gearset, that even ships with a free propeller.

In terms of cost, I think the outrunner broke the bank at 2.60 USD /pc. Ouch.

Despite my love for tiny motors, the one set of parts I've rarely stocked up on are the minute geared stepper motor assemblies that are commonplace among these listings.

There's a huge range to pick from, with the items below repesenting a fraction of the available wierd and wonderful assemblies to choose from!

And look at those prices too! Precision micro metal gearboxes, linear actuators on rails, lead screw sets that could let you build the worlds smallest Utilmaker, all for the extortionate sum of 1-2 USD each. Madness.

So, how is it that these parts are all so cheap, and more so, all so varied? Well, what you're looking at are usually the stock remnants of products that have failed to float on the market, or worse, never made it through the ramp up to production. This leaves a lot of parts, with nowhere to go, costing suppliers money to store, or dispose of. Parts like these tiny, high-spec geared linear actuators.

Most of these micro metal stepper gearboxes are from high-end auto focal optics for DSLR and CCTV cameras alike, and as such, they are well designed, to a high specification — optics need smooth motion, with a lot of torque to move the dampened, heavy glass elements.

And if you've ever taken apart an optical disc drive, you will likely recognize the larger linear rails often found within these devices, where they are tasked with moving the laser head carriage.

They are all manufactured at mind boggling scale, which drives the cost down to peanuts, and further more, when the parts are for a product that is not so common any more, they get even cheaper!

This is great for makers! These things are fractions of the cost, and often much smaller than a hobby servo, making them perfect for us to tinker with on the cheap — something that we are happy to see Mike Rankin starting to investigate over on his Twitter feed!

Having taken the financial plunge on a few of these micro stepper miniature linear actuators, we can only emphasize the confusion Rankin must have had when they turned up on his door a month later — these parts are cheap, so we're likely not going to spring for FedEx here!

But he's gotten them dutifully into line, and onto a custom ESP32-based controller PCB, in order to evaluate them for an upcoming secret project, which he teases us, involves this hardware, along with an high power IR laser diode.

Step to it!

As we've impressed already, these are simple 4 wire stepper motors, and having teased out enough information from the listing to determine the pin out of the motor coils, he selected the ST STSPIN220 driver IC in order to get these gears tuning.

It's a neat little IC, requiring only a few jellybean passives to support it, and takes up far less space PCB than an off-the-shelf stepper driver module. Sure, it doesn't come anywhere near those in terms of spec, but it's perfect for the little motors being driven by it here.

In conjunction with some roughly placed SMD limit switches, the ESP32 has no trouble in generating the PWM train and DIR pulses required by the SPIN220, and also won't have to worry about driving the slider carriage beyond the rail limits, and potentially damaging parts.

While he plans to release his schematic in due time, this is currently a proof-of-concept for Rankin.

But, he's given you all the information you might need already, and these parts are so cheap and so simple, that you can probably fill in any questions you might have right now by picking up a few bits, and simply having some fun playing around!

There are a few catches though...

While these parts are cheap, and can be fun to implement in a custom project, bear in mind two potential caveats before spooling up a production run a design based on up-cycled stock!

Firstly, you can expect no supplier support beyond what is listed on the item page — with the exception of additional information from the same part, but listed else where. Cross check your suppliers and the information the provide! Even then, be prepared for what is shipped to you to have some variance on spec, or even dimension!

Oh, and what is here today, may not be here tomorrow!

Remember, these are parts designed for a production run that may never happen again, or have even happened at first! These parts will likely never be made again, so if you find something you like, think carefully about future stock before designing it in.