ERRF 22: Baby Belt Promises Infinite Z For Under $200

Hackaday has been reporting on belt printers for around a decade now, since MakerBot released (and then quickly pulled) an automated build platform for their very first Cupcake printer. Turns out that not only has the concept been difficult to pull off from a technical perspective, but a murky patent situation made it tricky for anyone who wanted to bring their own versions to market. For a long time they seemed like the fusion reactors of desktop 3D printing — a technology that remains perennially just outside of our grasp.

But finally, things have changed. The software has matured, and there are now several commercial belt printers on the market. The trick now, as it once was for traditional desktop 3D printing, is to bring the costs down. Enter the Baby Belt, created by [Rob Mink]. This open-source belt printer relies on light-duty components and a largely 3D printed structure to get the price point down, though some will find its diminutive dimensions a bit too limiting…even if one of its axes is technically infinite.

If you’ve already got a printer and filament to burn, [Rob] is selling the part kit for just $130 USD. But even if you opt for the full ready-to-build kit, it will only set you back $180. Considering even the cheapest belt printers on the market now have a sticker price of more than $500, that’s an impressive accomplishment.

Of course, it’s hard to compare the Baby Belt with anything else on the market. For one thing, save for a few metal rods, its frame is made almost entirely from 3D-printed parts. Rather than the NEMA 17 stepper motors that are standard on even the cheapest of traditional desktop 3D printers, this little fellow is running on the dinky 28BYJ-48 steppers that you’d expect to find in a cheap toy. Then again, considering the printer only offers 85 x 86 mm in the X and Y axis, the structure and motors don’t exactly need to be top of the line.

What really sets this machine apart is the belt — while we’ve seen other makers go all out with their belt material, [Rob] has come up with an impressively low-tech solution. It’s a simple stack-up of construction paper, carpet tape, and fabric that you could probably put together with what you’ve got laying around the house right now.

Between that outer cloth layer and the printed frame, the Baby Belt offers a lot of room for customization, something which was on clear display at the 2022 East Coast RepRap Festival. The machines dotted several tables on the show floor, and you could tell their builders had a lot of fun making each one their own

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Automating Mini Blinds The Rental-Friendly Way

[Chris Mullins] wanted to automate opening and closing the slats of mini blinds in his apartment, and came up with a system to do it as a fun project. Manually opening and closing the slats means twisting a rod. Seems straightforward to automate that, but as usual when having to work around something that already exists, making no permanent alterations, complications arose.

The blinds are only 1 inch wide, leaving little room for mounting any sort of hardware. While there is a lot of prior art when it comes to automating blinds, nothing he found actually fit the situation [Chris] had, so he rolled his own.

The rod that is normally twisted to control the blinds is removed, and the shaft of a stepper motor takes its place. [Chris]’ mounting solution is made to fit blinds with narrow 1 inch tracks (existing projects he found relied on 2 inch tracks) and the 3D printed mount is fully adjustable, so the 28BYJ stepper motor can be moved into exactly the right position. Speaking of the stepper motor, the 28BYJ motor is unipolar but the A4988 driver he wanted to use is for bipolar steppers only. Luckily, cutting a trace on the motor’s PCB is all it takes to turn a unipolar motor into bipolar.

To drive the motor and provide wireless functionality, the whole thing works with a Wemos D1 ESP8266, an A4988 stepper driver, and a buck converter. While it worked fine as a one-off on a perfboard, [Chris] used the project as an opportunity to learn how to make a PCB using KiCad; the PCB project is here on GitHub and the ESP8266 runs the ESPHome firmware. Be sure to check out the project page on his blog for all the details; [Chris] links to all the resources there, and covers everything from a bill of materials to walking through configuration of ESPHome with integration into the open-source Home Assistant project.

Looking to control natural light but blinds aren’t your thing? Maybe consider automated curtains.