Is Box Turtle The Open Source AMS We’ve Been Waiting For?

Multimaterial printing was not invented by BambuLabs, but love them or hate them the AMS has become the gold standard for a modern multi-material unit. [Daniel]’s latest Mod Bot video on the Box Turtle MMU (embedded below) highlights an open source project that aims to bring the power and ease of AMS to Voron printers, and everyone else using Klipper willing to put in the work.

A 3d Printed panda with black and white filament
This isn’t a torture test, but it’s very clean and very cute.

The system itself is a mostly 3D printed unit that sits atop [Daniel]’s Voron printer looking just like an AMS atop a BambuLab. It has space for four spools, with motorized rollers and feeders in the front that have handy-dandy indicator LEDs to tell you which filament is loaded or printing. Each spool gets its own extruder, whose tension can be adjusted manually via thumbscrew. A buffer unit sits between the spool box and your toolhead.

Aside from the box, you need to spec a toolhead that meets requirements. It needs a PTFE connector with a (reverse) boden tube to guide the filament, and it also needs to have a toolhead filament runout sensor. The sensor is to provide feedback to Klipper that the filament is loaded or unloaded. Finally you will probably want to add a filament cutter, because that happens at the toolhead with this unit.  Sure, you could try the whole tip-forming thing, but anyone who had a Prusa MMU back in the day can tell you that is easier said than done. The cutter apparently makes this system much more reliable.

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Keep Track Of The Compost With LoRaWAN

Composting doesn’t seem difficult: pile up organic matter, let it rot. In practice, however, it’s a bit more complicated– if you want that sweet, sweet soil amendment in a reasonable amount of time, and to make sure any food-born pathogens and weed seeds don’t come through, you need a “hot” compost pile. How to tell if the pile is hot? Well, you could go out there and stick your arm in like a schmuck, or you could use [Dirk-WIllem van Gulik]’s “LORAWAN Compostheap solarpowered temperaturesensor” (sic).

The project is exactly what it sounds like, once you add some spaces: a solar-powered temperature sensor that uses LoRaWAN to track temperatures inside (and outside, for comparison) the compost heap year round. Electronically it is pretty simple: a Helltech CubeCell AB01 LoraWAN module is wired up with three DS18B20 temperature sensors, a LiPo battery and a solar panel. (The AB01 has the required circuitry to charge the battery via solar power.) Continue reading “Keep Track Of The Compost With LoRaWAN”

Head To Print Head: CNC Vs FDM

It’s a question new makers often ask: “Should I start with a CNC machine or a 3D Printer?”– or, once you have both, every project gets the question “Should I use my CNC or 3D printer?” — and the answer is to both is, of course, “it depends”. In the video embedded below by [NeedItMakeIt] you can see a head-to-head comparison for one specific product he makes, CRATER, a magnetic, click-together stacking tray for tabletop gaming. (He says tabletop gaming, but we think these would be very handy in the shop, too.)

[NeedItMakeIt] takes us through the process for both FDM 3D Printing in PLA, and CNC Machining the same part in walnut. Which part is nicer is absolutely a matter of taste; we can’t imagine many wouldn’t chose the wood, but de gustibus non disputandum est–there is no accounting for taste. What there is accounting for is the materials and energy costs, which are both surprising– that walnut is cheaper than PLA for this part is actually shocking, but the amount of power needed for dust collection is something that caught us off guard, too.

Of course the process is the real key, and given that most of the video follows [NeedItMakeIt] crafting the CNC’d version of his invention, the video gives a good rundown to any newbie just how much more work is involved in getting a machined part ready for sale compared to “take it off the printer and glue in the magnets.” (It’s about 40 extra minutes, if you want to skip to the answer.) As you might expect, labour is by far the greatest cost in producing these items if you value your time, which [NeedItMakeIt] does in the spreadsheet he presents at the end.

What he does not do is provide an answer, because in the case of this part, neither CNC or 3D Printing is “better”. It’s a matter of taste– which is the great thing about DIY. We can decide for ourselves which process and which end product we prefer. “There is no accounting for taste”, de gustibus non disputandum est, is true enough that it’s been repeated since Latin was a thing. Which would you rather, in this case? CNC or 3D print? Perhaps you would rather 3D Print a CNC? Or have one machine to do it all? Let us know in the comments for that sweet, sweet engagement.

While you’re engaging, maybe drop us a tip, while we offer our thanks to [Al] for this one.

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Tamagotchi Torture Chamber Is Equal Parts Nostalgia And Sadism

Coming in hot from Cornell University, students [Amanda Huang], [Caroline Hohner], and [Rhea Goswami] bring a project that is guaranteed to tickle the funny bone of anyone in the under-40 set, and sadists of all ages: The Tamagochi Torture Chamber.

Tamagotchi Torture Chamber displaying Tombstone
He’s dead, Jim.

In case you somehow missed it, Bandai’s Tamagochi is a genre-defining digital pet that was the fad toy at the turn of the millennium, and has had periodic revivals since. Like the original digital pet, there are three pushbuttons to allow you to feed, play with, and clean your digital pet. These affect the basic stats of happiness, health, food and weight in ways that will be familiar to anyone who played with the original Tamagochi. Just as with the original, mistreatment or neglect causes the Tamagochi to “die” and display a tombstone on the TFT display.

Where the “Torture Chamber” part comes in is the presence of an accelerometer and soft physics simulation– the soft physics gets an entire core of the Pi Pico at the heart of this build dedicated to it, while the other core handles all inputs, display and game logic. What this enables is the ability to bounce the digital pet off the walls of its digital home with an adorable squish (and drop in health stat) by tilting the unit. You can check that out in the demo video blow.

Is it overkill for a kids toy to have a full soft body simulation, rather than just a squish-bounce animation? Probably, but for an ECE project, it lets the students show off their chops… and possibly work out some frustrations.

We won’t judge. We will point you to other Tamagotchi-inspired projects, though: like this adorable fitness buddy, or this depressingly realistic human version.

If you’ve got an innovative way to torture video game characters, or a project less likely to get you on Skynet’s hitlist, don’t forget to send in a tip!

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Tiny Tellurium Orbits Atop A Pencil

We like scale models here, but how small can you shrink the very large? If you’re [Frans], it’s pretty small indeed: his Micro Tellurium fits the orbit of the Earth on top of an ordinary pencil. While you’ll often see models of Earth, Moon and Sun’s orbital relationship called “Orrery”, that’s word should technically be reserved for models of the solar system, inclusive of at least the classical planets, like [Frans]’s Gentleman’s Orrery that recently graced these pages. When it’s just the Earth, Moon and Sun, it’s a Tellurium.

The whole thing is made out of brass, save for the ball-bearings for the Earth and Moon. Construction was done by a combination of manual milling and CNC machining, as you can see in the video below. It is a very elegant device, and almost functional: the Earth-Moon system rotates, simulating the orbit of the moon when you turn the ring to make the Earth orbit the sun. This is accomplished by carefully-constructed rods and a rubber O-ring.

Unfortunately, it seems [Franz] had to switch to a thicker axle than originally planned, so the tiny moon does not orbit Earth at the correct speed compared to the solar orbit: it’s about half what it ought to be. That’s unfortunate, but perhaps that’s the cost one pays when chasing smallness. It might be possible to fix in a future iteration, but right now [Franz] is happy with how the project turned out, and we can’t blame him; it’s a beautiful piece of machining.

It should be noted that there is likely no tellurium in this tellurium — the metal and the model share the same root, but are otherwise unrelated. We have featured hacks with that element, though.

Thanks to [Franz] for submitting this hack. Don’t forget: the tips line is always open, and we’re more than happy to hear you toot your own horn, or sing the praises of someone else’s work. Continue reading “Tiny Tellurium Orbits Atop A Pencil”

The Most Satisfying Way To Commit

Have you ever finished up a bit of code and thought that typing “git push” in a terminal is just not a satisfying finish? So did [penumbriel], so he built a big red button he could smash instead.

This is a very simple hack: an Arduino sits inside a 3D-printed case that holds a big, red button. The case itself is very sturdily made to withstand a good satisfying smack: it has thick walls, brass insets, and rubber feet to protect the de The code for the Arduino is very, very simple: it spoofs a USB HID using the standard keyboard library, and automatically types out “git push” whenever the button is pressed. Or smashed, because you know you’re going to want to slam that thing. So far, so good– very innovative for 2006, right?

The detail that made this project stand out in 2025 was the technique [penumbriel] used for lettering– we’re always looking

With a simple soap-and-water mask, the cured silicone peels right off, leaving a clean label.

for new ways to make a good front panel. In this case, the letters were printed as a valley and filled with silicone adhesive. To protect the top surface of the print, soapy water was used as a mask. The silicone would not adhere to the wet plastic, so all [penumbriel] had to do was peel it off after it had cured, leaving solid white inside. It’s a neat trick, and a great way to use up an old tube of silicone before it goes hard. You could also use it for injection molding, but this is a great use for the dregs.

This might go well next to the programmer’s macro pad we featured a while back, but it really needs to stay as a big red button for maximum satisfaction.

 

Pi Pico Powers Parts-Bin Audio Interface

USB audio is great, but what if you needed to use it and had no budget? Well, depending on the contents of your parts bin, you might be able to use [Veyniac]’s Pico-Audio-Interface as a free (and libre! It’s GPL3.0) sound capture device.

In the project’s Reddit thread, [Veyniac] describes needing audio input for his homemade synth, but having no budget. Necessity being the mother of invention, rather than beg borrow or steal a device with a working sound card, he hacked together this lovely device. It shows up as a USB Audio Class 2.0 device so should work with just about anything, and offers 12-bit resolution and 4x oversampling to try and deal with USB noise with its 2-channel, 44.1 kHz sample rate.

Aside from the Pico, all you need is an LM324 op-amp IC and a handful of resistors and capacitors — [Veyniac] estimates about $10 to purchase the whole BOM. He claims that the captured audio sounds okay in his use, but can’t guarantee it will  be for anyone else, noise being the fickle beast that it is. We figure that sounding “Okay” has got to be pretty good, given that you usually get what you pay for — and again, [Veyniac] did build this in a cave with a box of scraps. Well, except for the cave part. Probably.

While the goal here was not to rival a commercial USB sound card, we have seen projects to do that. We’re quite grateful to [Omadeira] for the tip, because this really is a hack. If you, too, want a share of our undying gratitude (which is still worth its weight in gold, despite fluctuations in the spot price of precious metals), send in a tip of your own.