Commercialization And Innovation

The last year or two has seen relatively affordable multi-material printers hit the market, and the question that [Tom Nardi] and I were kicking around when he was writing up the 2025 year-in-review article was what it was going to mean for our folks. I don’t think he got it wrong per se, but his heading for that section “Grandma is 3D-Printing in Color” only tells half the story.

He did get that part right, though. We’ve certainly seen a flourishing of multi-material designs out there that take advantage of the availability of (usually) four colors. The ability to print in color has given life to the purely decorative models, of course. Think full-color Pokemon desktop toys, for instance. But even functional prints have benefited from contrasting color labels printed right into the box, not to even mention the multi-material supports that pull off easier and cleaner than ever before.

Since most of these multi-filament machines are pretty much locked down as far as hardware tinkering goes, our sights were firmly locked on what the end-user would do with the new capability. But we overlooked the third axis of 3D printering: the software hackers. And it’s precisely in this area of slicer and path-planning that we’ve seen some of the coolest developments this year. Why? Because people have the hardware in their hands that they need to test out the algorithms.

FullSpectrum and the more recent ImageMap are two techniques to get the missing in-between colors out of a four-filament printer, and in particular ImageMap tries to get the job done faster, and with fewer purges. We are amazed to see two different approaches to color blending popping up in just a few months of each other, and we have no doubt that work on this is going to continue.

At the end of the day, this really is just “put new tools in the hands of creative hackers, and they’ll find new ways to use them”, so we shouldn’t have been surprised at all. But if this is what comes out of the commercialization of the multi-material printer, what’s going to come when some of the more esoteric machine designs go mainstream? We can’t wait to find out!

Testing A 3D Printed Cycloidal Gearbox Design

Cycloidal gearboxes are a recurring theme in the hobbyist space due to the performance their promise in a compact package. They are capable of taking in a high-speed input and reducing it down to a set ratio with very low backlash, which theoretically makes them perfect for a wide range of projects where size and weight matter. Correspondingly, [Advanced Hobby Lab] has been tinkering with a 3D printed design to fit on NEMA 17 stepper motors.

For [Advanced Hobby Lab] the primary goal was to check that his cycloidal gearbox design was a real improvement over the planetary gearbox alternative. Although the 3D printed cycloidal drive worked well enough, some testing put real numbers to it, including a 92% efficiency. The gearbox also adds some noise over the stepper motor, but less so than the 3D printed planetary gearbox.

Of course, all of this is within the limits of FDM 3D printing and with a few metal parts, so there’s always room for improvement, but in the world of hobbyist 3D printed gearboxes it’s not a bad showing. The print and project files are available for anyone who is also feeling the itch. Of course, you can also opt for the dual-nested cycloidal design that we recently featured, as it promises to be even more compact, have even fewer parts and smoother action.

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A Compact Game Controller For Your Phone

[Gil Yankovitch] noted that playing games on a touchscreen phone gave up a certain something in terms of the tactile feedback one gets from real buttons. To that end, he was inspired to build a controller specifically for phones that solved this very problem.

The result was JoyFon. It’s a small gamepad built around the Raspberry Pi Pico, and can be put together around an RP2040 or an RP2350 as desired. It has four face buttons, a directional pad, and start and select buttons, as well as additional shoulder buttons up top in later revisions.

The JoyFon enumerates as a standard USB HID gamepad, so you could use it to play games on just about any PC, laptop, or tablet. However, the JoyFon is specifically designed for use with smartphones in the vertical orientation. This guided the design of the 3D printed enclosure, which positions the USB-C port to plug into the base of a phone, such that the buttons sit neatly beneath it. It does cover some of the phone screen, but that’s not always a problem when playing emulated games with a 4:3 or similar aspect ratio. The result is a button and screen layout not dissimilar to that of the original Game Boy handhelds.

We’ve seen some other great custom controller builds over the years, like this fantastic design using keyswitches.

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Casual Repair And Maintenance On An Amiga 1000

Recently [Drygol] had an Amiga 1000 system over for some repairs as well as maintenance and general TLC. This is a Motorola 68000-based home computer from 1985 that also has the distinction of being the first Amiga system to be released by Commodore. At a time when the IBM PC was still strutting its monochrome and EGA graphics alongside PC speaker beeps, the Amiga 1000 featured relatively high-res graphics and advanced stereo audio courtesy of special accelerator chips.

Overall the system was in a pretty good condition, even coming with the very nifty modern Parceiro expansion that adds 8 MB of fast RAM, an SD card slot and RTC. This thus meant that they mostly just had to perform the typical maintenance task, such as recapping the PSU and mainboard, as well as recapping and lubing up the floppy drive. The original 230 VAC fan in the PSU also got swapped with a 12V unit that was much quieter.

After disassembling the keyboard for some deep cleaning and retr0brighting, a little glitch in the form of the use of a too long screw by a previous owner was addressed, as well as a broken plastic clip. With how little attention the Amiga 1000 received after its release it’s good to see some of these units still kicking.

Turning Glass Into A Touch-Sensitive Button

Although generally glass isn’t associated with touch-sensitive surfaces, the addition of an ITO (indium tin oxygen) coating adds the exciting property of not only being transparent to the visible light part of the electromagnetic spectrum, but also of being electrically conductive. The logical result is that fine folk like [Sokol] simply had to use their newly acquired ITO-coated glass to make a button out of.

Here the easy option is of course to just use it as a capacitive sensor where the conductive ITO layer is used for the capacitive charge and the glass provides the insulator, but here we see it demonstrated how to create a pressure-sensitive implementation instead.

The measured conductivity on the ITO-coated glass in the video is pretty good, at just over 20 Ohm. This thus makes said capacitive button very easy to achieve. To make it a touch-sensitive button, two pieces of glass are used, with the ITO sides facing. Paper is used to create a spacer, after which the slight flex of the glass allows for the two ITO surfaces to touch, completing the circuit.

This is somewhat similar to how resistive touch screens work, with the position of the finger or stylus determined by the resistance between the two sides. In a hobbyist setup this would make it fairly easy to create a multi-position touch screen using just two pieces of glass and some firmware.

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A Complex Way To Push A Button

We’ve likely all looked at a simple problem in our lives and thought that it would be an easy fix, only to realize that the project is enormously more complicated than we first realized. Whether that’s starting a home improvement project, doing a quick repair to a bicycle or car, or trying to install an obscure piece of software on a Linux machine, the amount of time we budget for these tasks often ends up woefully underestimated. []’s night light needs to have its brightness set every night, and it seems easy enough to get a microcontroller to automate that, right?

Well, upon opening the small device, the first issue is that there is no labeling on any of the parts, so simply adding a jumper on to existing microcontroller pins without damaging anything wouldn’t easily be possible. Adding a secondary microcontroller is the next logical step, but the power supply in the night light is extremely underpowered so using even the smallest Raspberry Pi or off-the-shelf Arduino was out of the question too. [Oscar] instead chose an ATtiny85, which solves the power requirement issue, but these are a bit more of a challenge to program without a USB device. From there, it needs a transistor wired in to the circuit to actually push the button for him, plus a few support resistors, so [Oscar] actually had a PCB custom-built to hold all of these components.

Even after all of that, the space within the night light enclosure made installing the PCB a challenge, but in the end he has a device which, when his home automation system powers on the plug for the nightlight, automatically boots up and pushes the switch the required number of times and then puts itself to sleep. We’d call that a success even after the colossal effort getting this inexpensive, small light working the way he wanted. There are some other low-powered solutions for problems like these too, as long as being battery-powered isn’t a dealbreaker.

Tiny Desktop Robot Has Radar

One thing our futuristic world is largely lacking in is droids and robot companions and the like. [solitary dev] is helping to rectify that problem by building a little robot called TongDou.

As [solitary dev] tells it, TongDou is a “tiny open-source desktop gremlin.” An ESP32-S3 serves as TongDou’s brain, buried inside a tasteful brass chassis. An OLED display is TongDou’s face, and he uses a pair of wheels driven by gearmotors for locomotion. A speaker plays back pre-recorded voice lines, while a 24 GHz radar and an IMU enables TongDou to keep track of the space it’s moving through. They are publishing the design files on GitHub so other makers can build their own if so desired.

[solitary dev] hopes to develop TongDou into something to make a “workspace feel less dead.” It’s not dissimilar from the way studios used to use robots to liven up otherwise hackneyed movies and TV shows, and we could absolutely use some of that whimsy in the real world. We’ve featured other fun desktop companions before, too.

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