The big white thing is is the CO2 exhaust bag.

Liquid CO2 For Grid Scale Energy Storage Isn’t Just Hot Air

January 2, 2026 by 5 Comments

There’s folk wisdom in just about every culture that teaches about renewable energy — things like “make hay while the sun shines”. But as an industrial culture, we want to make hay 24/7 and not be at the whims of some capricious weather god! Alas, renewable energy puts a crimp in that. Once again, energy supplies are slowly becoming tied to the sun and the wind.

Since “Make compute while the wind blows” doesn’t have a great ring to it, clearly our civilization needs to come up with some grid-scale storage. Over in Sardinia they’re testing an idea that sounds like hot air, but isn’t — because the working gas is CO2. 

The principle is simple: when power is available, carbon dioxide is compressed, cooled, and liquefied into pressure vessels as happens at millions of industrial facilities worldwide every day. When power is required, the compressed CO2 can be run through a turbine to generate sweet, sweet electricity. Since venting tonnes of CO2 into the atmosphere is kind of the thing we’re trying to avoid with this whole rigmarole, the greenhouse gas slash working fluid is stored in a giant bag. It sits, waiting for the next charge cycle, like the world’s heaviest and saddest dirigible. In the test project in Sardinia — backed by Google, amongst others — the gas bag holds 2000 tonnes and can produce 20 megawatts of power for up-to 10 hours.

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Print Your Own Standardized Wire Spool Storage

January 2, 2026 by 1 Comment

Hardware hackers tend to have loads of hookup wire, and that led [firstgizmo] to design a 3D printable wire and cable spool storage system. As a bonus, it’s Gridfinity-compatible!

The slot to capture loose ends is a nice touch, and the units can be assembled without external hardware.

There are a lot of little design touches we love. For example, we like the little notch into which the wire ends are held, which provides a way to secure the loose ends without any moving parts. Also, while at first glance these holders look like something that goes together with a few screws, they actually require no additional hardware and can be assembled entirely with printed parts. But should one wish to do so, [firstgizmo] has an alternate design that goes together with some M3 bolts instead.

Want to adjust something? The STEP files are included, which we always love to see because it makes modifications to the models so much more accessible. One thing that hasn’t changed over the years is that making engineering-type adjustments to STL files is awful, at best.

If there is one gotcha, it is that one must remove wire from their old spools and re-wind onto the new to use this system. However, [firstgizmo] tries to make that as easy as possible by providing two tools to make re-spooling easier: one for hand-cranking, and one for using a hand drill to do the work for you.

It’s a very thoughtful design, and as mentioned, can also be used with the Gridfinity system, which seems to open organizational floodgates in most people’s minds. Most of us are pinched for storage space, and small improvements in space-saving really, really add up.

Making The Fastest LEGO Technic Air-Powered Engine

January 1, 2026 by No comments

Just because LEGO Technic is technically a toy doesn’t mean that you cannot do solid engineering with it, like building air-powered engines. After first building a simple air-powered piston engine, this time around [Jamie’s Brick Jams] sought to not only optimize the engine, but also build a clutch and something to power with said engine.

The four-piston design in radial configuration. (Credit: Jamie's Brick Jams, YouTube)
The four-piston design in radial configuration.

The piston head is one of the handful of 3D printed parts, with the new design featuring twin rubber o-rings as a seal instead of a single big one as in the old design. This incidentally matches the multiple seal rings on an internal combustion engine’s pistons, probably for similar blow-by related reasons. The air hose diameter was also increased from 2 to 3 mm to give the engine a larger volume of air to work with, which along with a new flywheel gave a lot more torque. Next the piston rod length was optimized.

The final radial 4-piston engine turns out to work pretty well, with the clutch engaging smoothly. This was used to drive a DIY generator that turned out to produce about 3 Watt of usable power in its final configuration at 6 V, though it’s admittedly a rather crude generator that could be further optimized. When trying a twin-piston configuration with the highest air pressure before air hoses began to pop off, it hit a dizzying 14,600 RPM.

These aren’t half bad results for some LEGO Technic together with some 3D printed bits, rubber o-rings and some lube.

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A tab-based terminal window is shown, with the label “brow6l – Hackaday.” The Hackaday website is visible in the upper part of the terminal screen, and in the lower part is a text display containing information about the website and interface information.

Terminal-Based Web Browsing With Modern Conveniences

January 1, 2026 by 5 Comments

Programmers hold to a wide spectrum of positions on software complexity, from the rare command-line purists to the much more common web app developers, and the two extremes rarely meet. One point of contact, though, might be [Jan Antos]’s Brow6el, which uses sixel graphics to display a fully graphical web browser within a terminal.

Behind the scenes, the Chromium Embedded Framework renders webpages headless, then Brow6el uses libsixel to convert the rendered output image to sixels, a simple kind of console-based graphics representation, which it then outputs to the terminal. It regularly re-renders the page to catch page updates and display them in real time, and it can send mouse or keyboard input back to the webpage. For more advanced work, it also has a JavaScript development console, and it’s possibly to manually inject scripts into rendered webpages, or inject them automatically using URL match patterns. Continue reading “Terminal-Based Web Browsing With Modern Conveniences” →

Putting A Cheapo 1800W DC-DC Boost Converter To The Test

January 1, 2026 by 11 Comments

These days ready-to-use DC-DC converters are everywhere, with some of the cheaper ones even being safe to use without an immediate risk to life and limb(s). This piques one’s curiosity when browsing various online shopping platforms that are quite literally flooded with e.g. QS-4884CCCV-1800W clones of a DC-DC boost converter. Do they really manage 1800 Watt even without active cooling? Are they perhaps a good deal? These were some of the questions that [Josh] over at the [Signal Drift] channel set out to answer.

The only real ‘datasheet’ for this module seems to come courtesy of a Floridian company who also calls it the 36843-PS, but it features specifications that are repeated across store listings so it might as well by the official ‘datasheet’. This module is marketed as being designed for the charging of lead-acid and similar batteries, including the boosting of PV solar panel outputs, though you’d really want to use an MPPT charger for that.

With this use case in mind, it’s probably no surprise to see on the oscilloscope shots under load that it has a tragic 100 kHz switching frequency and a peak-to-peak noise on the output of somewhere between 1-7 VDC depending on the load. Clearly this output voltage was not meant for delicate electronics.

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Welded frame and cylinders for T1 #5550

Building A Steam Loco These Days Is Nothing But Hacks

January 1, 2026 by 13 Comments

The Pennsylvania Railroad (PRR)’s T1 class is famous for many reasons: being enormous, being a duplex, possibly having beaten Mallard’s speed record while no one was looking… and being in production in the 21st century. That last fact is down to the redoubtable work by the PRR T1 Steam Locomotive Trust, who continued their efforts to reproduce an example of these remarkable and lamentably unpreserved locomotives in the year 2025.

They say that 2025 was “the year of the frame” because the frame was finally put together. We might say that for the PRR Trust, this was the year of welding. Back when the Baldwin and Altoona works were turning out the originals, the frames for steam locomotives were cast, not welded. There might not be anywhere on Earth to get a 64′ long (19.5 m), 71,000 lbs steel casting made these days. Building it up with welded steel might not be perfectly accurate, but it’s the sort of hack that’s needed to keep the project moving.

The cylinders, too, would have been bored-out castings back the day. Getting the four (it’s a duplex, remember) assemblies cast as one piece didn’t prove practical, so T1 #5550 will have welded cylinders as well. Given modern welding, we expect no problem with holding steam pressure. The parts are mostly machined and will be welded-together next year.

The giant wheels of the locomotive have been cast, but need to be machined. It’s not impossible to believe that locomotive #5550 will be on its frame, on its wheels, in 2026. The boiler is already done and the injectors to get water into it have been reinvented, which can perhaps be considered another hack. Continue reading “Building A Steam Loco These Days Is Nothing But Hacks” →

A giant pokeball is the best place to hide this holiday season.

Our New Years Wish Is To Hide In A Giant Pokéball

January 1, 2026 by 4 Comments

Between the news, the world situation, and the inevitable family stresses that come this time of year, well — one could be excused for feeling a certain amount of envy for those adorable pocket monsters who spend their time hidden away in red-and-white orbs. [carlos3dprint] evidently did, but he didn’t just dream of cozy concave solitude: he made it happen, with 3D printing and way too much post-processing.

Arguably 3D printing is not the ideal technique for such a large build, and even [carlos], despite the 3dprint in his handle, recognized this: the base frame of the sphere is CNC-routed plywood. He tried to use Styrofoam to make a skin, but evidently he’d lost access to the large CNC cutter he’d borrowed for the plywood frame at that point, as he was trying to do the cuts by hand. It still seems like it wouldn’t have be any worse than the little printed blocks from four different printers he eventually hot-stapled into a shell.

We only say that because based on his description of how much resin and filler went into creating a smooth outer surface on his Pokéball, the raw surface of the prints must have been pretty bad before fiberglass was applied. Still, it’s hard to argue with results, and the results are smooth, shiny and beautiful after all the sanding and painting. Could another technique have been easier? Maybe, but we hack with what we have, and [carlos] had 3D printers and knows how to make the best of them.

The interior of the ball is just large enough for a cozy little gaming nook, and no guesses what [carlos] is playing inside. The Instructable linked above doesn’t have many interior photos, though, so you’ll have to check the video (embedded below) for the interior fitting out, or jump to the tour at about the 15 minute mark.

Given ongoing concerns about VOCs from 3D printers, we kind of hope the Bulbsaur-themed printer he’s got in there is decorative, but it’s sure a nice homage to the construction method. Other pokeballs featured on Hackaday have been much smaller, but we’ve always had a soft spot for scaled-up projects.

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