Thermoacoustic Stirling Engine Is Now Fully 3D Printable

Would you like to make your own energy? Why, who doesn’t in this era of rising costs! A Stirling engine always looks like a good fit for that: highly efficient, with no risk of a boiler explosion. A thermoacoustic Stirling engine looks even better, since it has only one moving part at the output end. A thermoacoustic Stirling engine you can 3D print yourself looks best of all, and that’s what [my engines] has on offer, now that even the burner and hot end of his thermoacoustic engine are designed for SLA metal printing.

We previously reported on the open-source engine, but there’ve been some improvements worth talking about. For one thing, he’s integrated a biogas/methane burner directly inside the 3D-printable hotend. For another, that 3D-printed design allows for an excellent heat exchange geometry that would be very hard to get any other way. The whole thing is open source with plans available at OwnEnergy.org, where you can find links to the apparently mandatory Discord channel and now an old-style forum to actually collaborate on the design, which is open-source. The site is also now the home of all data and discussion about [my engines]’s homescale biogas plant, which is the power source for this little engine.

If you’d rather print a combustion engine, you can do that, too, but you’ll need more “vitamins” than this unit requires.

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Samsung Printer Is The Next Frontier Of Minecraft Servers

While DOOM remains the undisputed champion of ‘game you play on every piece of hardware’ it seems that the role of ‘game you play on everything just because you can’ is slowly being shifted to Minecraft, as we have yet another Minecraft server somewhere Minecraft has no business being served– in this case, a Samsung Printer.

The hack actually requires opening up the printer to get at the debug ports to bang your way in via serial, but as any security expert will tell you, once the black hats have physical access to a machine, they own it. That isn’t to say it’s easy– [vimpo] had to dump the firmware and find an exploit. Since it’s 2026 [vimpo] tried to get an LLM to do all that hard work for him, and while it helped with identifying functions in the dump, ultimately the hacking still fell upon [vimpo]’s human intelligence, though not before burning through millions of tokens.  Having found a good old fashioned UDP overflow exploit, he’s gets control of the printer and puts an improved version of his lightweight Minecraft server, UCraft, on it.  Like the server, the exploit is also on GitHub but you’ll very likely need the exact same printer to get it to work: a Samsung C410W with firmware V3.00.02.20, DEC-15-2015. One important caveat is that while you can still use the printer as intended after this hack, you cannot do so while playing Minecraft: it crashes the server if you try. Good to know.

In case you’re wondering, yes, this is the same guy who got a Minecraft server running on a light-bulb, which arguably more impressive. Where he might mine and/or craft next is anybody’s guess. Somebody else already did the ESP32-C3, and while we suspect nothing will ever beat the 1960s Univac implementation for sheer impracticality, we’re willing to be surprised.

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Historical Hack: Henri Giffard’s Steam Injectors

Here’s a historical hack for you: you have a big, rolling pressurized kettle, also known as a steam locomotive. It needs water to make up for the steam constantly chuff-chuff-chuffing away, or bad things happen. How do you get water from an unpressurized tender into a high pressure boiler with no moving parts? What you need is a some way to inject steam with no moving parts — a steam injector, if you will. [Marc Flint] found that the steam injectors were the hardest part of a loco to understand, so he made a video for all of us once he’d figured it out.

The steam injector isn’t a new idea. [Henri Giffard] came up with it back in the 1850s to replace expensive and maintenance-hungry pumps. It’s rather ingenious and uses the fluid mechanics uncovered by another European bloke by the name of Bernoulli. First, the high-pressure steam from the boiler goes through a converging-diverging nozzle to drop its pressure and speed its flow up, just as you’d guess if you’ve seen Bernoulli’s laws. Even more vacuum-inducing is the presence of water: the steam, already cooled by its expansion, hits the water in the pipe open to the tender, and condenses into it, shrinking a couple of orders of magnitude, creating a vacuum that draws in no small quantity of feed water. That one we did not expect from Bernoulli, but it makes sense. So how to get from below atmospheric pressure to the 180-odd PSI or more in the boiler?

Well, the water is now moving at a good clip, between the Venturi effect and the momentum gained from absorbing that steam, so another converging nozzle is the trick. Bernoulli’s law, once more! A one-way valve lets the now-pressurized water into the boiler, with a gap in between to dump water while the pressure builds up. It’s a clever trick, and since the steam coming from the boiler makes it back inside along with at least some of its heat energy, it’s much more efficient in both coal and water than running a pump. It’s also a bit of a head scratcher how it works unless someone sits you down to explain it, so we’re glad [Marc] did.

Not many of us are likely to use this knowledge directly — unless we’re firing up a 90 year old boiler or building a new steam locomotive — but seeing how great engineers of years past made use of basic physical laws can serve both as education and inspiration.

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Compress Links For Optimal QR Codes

Link shorteners have been a staple of the online world for over two decades now, but they’ve got some issues– for one thing, it’s totally non-transparent where the link actually goes, leaving you open to all sorts of shenanigans, of which RickRolling is probably the best case. For two, your traffic is going through an external service who may have their own nefarious intent. [PortalRunner] had an idea: don’t shorten the link, but compress it.

You see, a traditional URL shortener like tinyurl just generates a random code and associates that with your original link in its database. That’s fine, but you’re relying on a third party database. The alternative is to take the URL, encode it in some way, and apply some compression algorithm to the data. If the encoding and compression are open-source– which [Portal ]’s absolutely are— then you can check yourself before following the link, and/or self-host the whole thing for piece of mind. As a bonus [Portal]’s Ha.mr– that’s pronounced Hammer– also gives you a QR code optimized for easy scanning. QR codes have a specific alphanumeric character set built in, and it isn’t the full UTF-8– if you naively use random text, you’re in byte mode, which needs a lot more QR real estate. Or inverting that, the fewer bits it has to store, the easier a qr code is to scan at the same size. The text version of the compressed links can use UTF-8– including emoticons– but they don’t have to.

The whole project has a “why isn’t everyone doing it this way” vibe about it. We’d probably want to self-host this if we were using it seriously– [Portal] put this together on a lark and makes no promises it will be online forever–but again, this is open source, so we can. [Portal] is using normal compression algorithms here, but if you really want to squeeze text, use a neural net. 

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Store Tunes On Paper And Stream Them Over LoRA

Some projects seem too good to be true until you dig into it and find the secret magic that makes it all work. Take Paper Tunes by [Makestreame], a project which purports to store a song on a single sheet of paper via QR code and transmit the data over LoRA. If it was a MIDI sequence, maybe. But the promise of Paper Tunes is to take any MP3 and give it this treatment, and that just seems like an impossible level of compression at first glance.

The music is heavily compressed, make no doubt about that. There’s samples in the Instructables link above and in the video below, but it sounds far better than it has any right to. The secret is Meta’s EnCodec neural codec, which like you’d guess uses neural nets to squeeze the absolute minimum information needed to reconstruct a sample. With it [Makestreame] is able to get a 2.9 MB MP3 file down to just 21.44 kB.

Of course, that’s still not going to fit in a 3.3 kB QR code. But by simply making eight of them, [Makestreame] is able to fit the song onto the front and back of a piece of paper. Yes, each song has an “A” and a “B” side — and you thought flipping a record halfway through got old fast. Having to scan eight codes to get one song may strike some as a bit silly, but we do enjoy some silly things here.

The same EnCodec compression that gets the song so tiny as to fit in a brace of QR codes is obviously also what enables its transmission over LoRA. While it’s got far lower bandwidth than something like WiFi, 21 kB is well within its limits. It’s often said that LoRA isn’t suitable for audio, but this project is another example that one person’s “unsuitable” is another person’s “challenge accepted”.

We’ve seen other LoRA audio projects before. Speaking of things not suitable for audio, we once featured an entire album crammed onto a floppy disk. Continue reading “Store Tunes On Paper And Stream Them Over LoRA”

Edison Motors Offering All-Mechanical Trucks, At Least To Start

We’ve been following Canadian startup Edison Motors for some time now, but their latest offering caught us a bit off guard — their BDE series truck will be offered first without the electric hybrid drive that first piqued our interest. They make a good case for why in the video below, in which the production prototype tows around a junked Nikola semi as a sort of memento mori of what Edison does not want to end up as.

Now, make no mistake: Edison Motors is going to be selling the series-hybrid version of these big rigs eventually. That truck will have a Scania diesel rated at 500 kW driving electric motors rated at a combined 1800 kW peak power — that’s 2400 ponies. Along with the diesel generator those ponies will be driven by a big o’l battery, but none of that is in the truck in the video. It’s the same cab, and the same frame, but in order to get some revenue in while jumping regulatory hurdles and working the kinks out of the hybrid drive, they put a conventional Cummins diesel and 16-speed transmission in the “Big D” as the truck is known.

The business case makes sense: they don’t want to have their single new product hit a snag, possibly require a recall, and fall into bankruptcy the way the electric truck company Nikola did. The conventional drivetrain also lets them prove their engineering prowess to companies that might like the idea of a Made-in-Canada truck, but be nervous about new technology from a new company.

If you want to know more about the whole diesel-electric scheme, we covered that last year. Edison also has plans to offer its hybrid drive technology for smaller trucks in kit form, which is perhaps the most exciting part from a hacker perceptive.

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One Man’s Perfect Retro-Style Monitor Takes All Inputs

Perfection is an inherently subjective measure, in that one must choose the criteria against which to measure. A perfect circle is an absolutely rubbish octagon, for example. So when you see that [RetroBuiltGames] declares that he has built “the perfect multi-input display for retro gaming and vintage computing” — dubbed the “PixelVision AV1000 MKII”— keep in mind that he means the perfect display for his use case. That’s who he’s building it for, after all! The degree to which you find his product perfect is going to depend by-and-large how similar his use case is to yours. In that sense detailed explanations in the design/build video embedded below may be more valuable than the STEP files and PCBs in the GitHub link above– that way if your use case isn’t identical, you can perhaps learn something on the journey to build your own perfect monitor.

For [RetroBuiltGames] the aesthetic was obviously a big part of it– he’s inspired by the Amiga 1000’s monitor, and a tiny tilting Sony CRT TV.  He was obviously looking for many inputs, as given by the title, and he has an unusually high interest in pixel density for a retro enthusiast. Hence a 9.7″ 2K iPad display forms the basis of the project. The multi-input aspect is provided by a retrotink clone whose PCB lives in a bulge on the back of the unit that could easily house an SBC if you wanted an all-in-one emulation station– it already has a couple of decent speakers mounted in the sides.

Another big piece of the puzzle we don’t see enough of in such projects is Design For Manufacturing– the manufacturing method of choice being FDM 3D printing. The whole assembly was designed in chunks that can be easily printed  with the most visible surface flat on the bed – and if assembly proved difficult, than the parts were redesigned. His explanations aren’t a full DFM course by any means, but it’s good to see these things considered. If you need more detail on that front, we’ve featured plenty of such guides before.

We’re particularly taken by the conceit of creating his own packaging for the unit, and going to the effort of filming an unboxing video for a product he made himself. It’s just a bit of silly fun. We’ve seen boxes before, but generally speaking that sort of thing is saved for when a project becomes a product.

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