Benchy, printed upside down on [Josh's] Core R-Theta printer.

Non-planar Slicing Is For The Birds

April 20, 2025 by Tyler August 15 Comments

When we say non-planar slicing is for the birds, we mean [Joshua Bird], who demonstrates the versatility of his new non-planar S4-Slicer by printing a Benchy upside down with the “Core R-Theta” printer we have featured here before.

A benchy model, upside down, with the path from the end of the prow to the printbed highlighted. — S4 slicer uses the path from any point (here, Benchy’s prow) as its basis…

This non-planar slicer is built into a Jupyter notebook, which follows a relatively simple algorithm to automatically generate non-planar toolpaths for any model. It does this by first generating a tetrahedral mesh of the model and then calculating the shortest possible path through the model from any given tetrahedron to the print bed. Even with non-planar printing, you need to print from the print-bed up (or out).

Quite a lot of math is done to use these paths to calculate a deformation mesh, and we’ll leave that to [Joshua] to explain in his video below. After applying the deformation, he slices the resulting mesh in Cura, before the G-code goes back to Jupyter to be re-transformed, restoring the shape of the original mesh.

… to generate deformed models for slicing, like this.

So yes, it is G-code bending as others have demonstrated before, but in a reproducible, streamlined, and straightforward workflow. Indeed, [Josh] credits much of the work to earlier work on the S^3-Slicer, which inspired much of the logic and the name behind his S4 slicer. (Not S4 as in “more than S^3” but S4 as a contraction of “Simplified S^3”). Once again, open source allows for incremental innovation.

It is admittedly a computationally intensive process, and [Joshua] uses a simplified model of Benchy for this demo. This seems exactly the sort of thing we’d like to burn compute power on, though.

This sort of non-planar 3D printing is an exciting frontier, one which we have covered before. We’ve seen techniques for non-planar infill, or even to print overhangs on unmodified Cartesian printers, but this is probably the first time we’ve seen Benchy given the non-planar treatment. You can try S4 slicer for yourself via GitHub, or just watch the non-planar magic in action after the break. Continue reading “Non-planar Slicing Is For The Birds” →

Rockbox 4.0 Released

April 19, 2025 by John Elliot V 23 Comments

It’s traditional to launch new software on April Fool’s Day, which is when we heard that Rockbox 4.0 has been released. But, in this case, the venerable MP3 firmware actually did update after a long absence. It’s great to see that good old Rockbox is still kicking along. We first mentioned Rockbox here at Hackaday approaching 20 years ago. How time flies. There used to be a whole ‘scene’ around hacking Personal Media Players (PMPs), also known as “MP3 Players”.

We tracked down Rockbox contributor [Solomon Peachy] to ask for some simple advice: If someone wants to install Rockbox on a personal media player today, what hardware should they buy? [Solomon] referred us to the AIGO EROS Q / EROS K, which is the only compatible hardware still being manufactured and sold. Beyond that, if you want to buy compatible hardware, you’ll need to find some secondhand somewhere, such as eBay. See the Rockbox Wiki for supported hardware.

Smartphones and streaming services have subsumed the single-purpose personal media player. Will you put the new Rockbox on something? Let us know in the comments.

Frankenflair 58: Manual Roots, Advanced Brew

April 19, 2025 by Matt Varian 2 Comments

The user interface of things we deal with often makes or breaks our enjoyment of using a device. [Janne] thinks so, he has an espresso machine he enjoys but the default controls were not what he was looking for and so in true hacker fashion he took what was and made it his own.

Continue reading “Frankenflair 58: Manual Roots, Advanced Brew” →

The TMSR-LF1 building seen from the sky. (Credit: SINAP)

China’s TMSR-LF1 Molten Salt Thorium Reactor Begins Live Refueling Operations

April 19, 2025 by Maya Posch 33 Comments

Although uranium-235 is the typical fuel for commercial fission reactors on account of it being fissile, it’s relatively rare relative to the fertile U-238 and thorium (Th-232). Using either of these fertile isotopes to breed new fuel from is thus an attractive proposition. Despite this, only India and China have a strong focus on using Th-232 for reactors, the former using breeders (Th-232 to U-233) to create fertile uranium fuel. China has demonstrated its approach — including refueling a live reactor — using a fourth-generation molten salt reactor.

Continue reading “China’s TMSR-LF1 Molten Salt Thorium Reactor Begins Live Refueling Operations” →

A nuclear coolant tower dwarfs other buildings in the area.

They Hacked A Nuclear Power Plant! Whoops! Don’t Make A Sound!

April 19, 2025 by John Elliot V 3 Comments

What do you do with an unused nuclear reactor project? In Washington, one of them was hacked to remove sound, all in the name of science.

In 1977, a little way outside of Seattle, Washington Nuclear Projects 3 and 5 (WNP-3 and WNP-5) were started as part of Washington Public Power Supply System (WPPSS, pronounced “whoops”). They ran over budget, and in the 80s they were mothballed even though WNP-3 was nearly complete.

Continue reading “They Hacked A Nuclear Power Plant! Whoops! Don’t Make A Sound!” →

Hydroplaning RC Jet Boat Steers Clear Of Convention

April 19, 2025 by Seth Mabbott 19 Comments

[CovaConcepts], who has a background in motorsports, has been busy designing an unconventional radio-controlled watercraft she calls the HydraJet.

There are two key design decisions that make the HydraJet what it is. First, she chose to propel the boat by pushing against the air via an electric ducted fan (EDF) rather than the water via a traditional water propeller. This simplified construction and made it more affordable, partly because she already had the fan on hand.

Her other design choice was to use wings underneath the boat to lift it out of the water. Not as hydrofoils, where the wings ride below the surface of the water, but for hydroplaning where the wings ride on the surface of the water. Lifting the vehicle out of the water, of course, reduces drag, improving performance as we’ve often seen with high speed watercraft (including RC models) as well as slower bicycle-powered ones. The choice to rely on hydroplaning also reduces the complexity of the design. Certain hydrofoil designs need to make adjustments in order to keep the vehicle at a steady level, whereas a hydroplaning wings can use a static angle. Hydrofoils also must overcome challenges to maintain stability.

[CovaConcepts] hopes to eventually scale the HydraJet up large enough to carry human passengers and we’re looking forward to the opportunity to take it for a spin around the lake.

Continue reading “Hydroplaning RC Jet Boat Steers Clear Of Convention” →

Vibing, AI Style

April 19, 2025 by Elliot Williams 48 Comments

This week, the hackerverse was full of “vibe coding”. If you’re not caught up on your AI buzzwords, this is the catchy name coined by [Andrej Karpathy] that refers to basically just YOLOing it with AI coding assistants. It’s the AI-fueled version of typing in what you want to StackOverflow and picking the top answers. Only, with the current state of LLMs, it’ll probably work after a while of iterating back and forth with the machine.

It’s a tempting vision, and it probably works for a lot of simple applications, in popular languages, or generally where the ground is already well trodden. And where the stakes are low, as [Al Williams] pointed out while we were talking about vibing on the podcast. Can you imagine vibe-coded ATM software that probably gives you the right amount of money? Vibe-coding automotive ECU software?

While vibe coding seems very liberating and hands-off, it really just changes the burden of doing the coding yourself into making sure that the LLM is giving you what you want, and when it doesn’t, refining your prompts until it does. It’s more like editing and auditing code than authoring it. And while we have no doubt that a stellar programmer like [Karpathy] can verify that he’s getting what he wants, write the correct unit tests, and so on, we’re not sure it’s the panacea that is being proclaimed for folks who don’t already know how to code.

Vibe coding should probably be reserved for people who already are expert coders, and for trivial projects. Just the way you wouldn’t let grade-school kids use calculators until they’ve mastered the basics of math by themselves, you shouldn’t let junior programmers vibe code: It simultaneously demands too much knowledge to corral the LLM, while side-stepping any of the learning that would come from doing it yourself.

And then there’s the security side of vibe coding, which opens up a whole attack surface. If the LLM isn’t up to industry standards on simple things like input sanitization, your vibed code probably shouldn’t be anywhere near the Internet.

So should you be vibing? Sure! If you feel competent overseeing what [Dan] described as “the worst summer intern ever”, and the states are low, then it’s absolutely a fun way to kick the tires and see what the tools are capable of. Just go into it all with reasonable expectations.