The Decisioninator Decides Dinner, Saves Marriage

September 5, 2025 by Tyler August 14 Comments

For something non-explosive, this might be the most American project we’ve featured in a while. [Makerinator]’s domestic bliss was apparently threatened by the question “what shall we have for dinner”– that’s probably pretty universal. Deciding that the solution was automation is probably universal to software devs and associated personalities the world over. That the project, aptly called “The Decisioninator” apes a popular game-show mechanic to randomly select a fast-food restaurant? Only people with 100-octanes of freedom running through their veins can truly appreciate its genius.

In form factor, it’s a tiny slot machine which [Makerinator] fabbed up on his laser cutter. The lovely “paintjob” was actually a print out with dye-sublimation ink that was transferred to plywood before laser cutting. Mounted to this are illuminated arcade buttons and a small ISP display. The interface is simplicity itself: the big button spins a virtual “wheel” on the display (with sound effects inspired by The Price is Right) to tell the family what deliciously unhealthy slop they’ll be consuming, while the other button changes decision modes. Of course you can pick more than just dinner with The Decisioninator. You need only decide what spinners to program. Which, uh, that might be a problem.

Luckily [Makerinator] was able to come up with a few modes without recursively creating a The Decisioninator-inator. He’s got the whole thing running on a Pi4, which, with its 1980s supercomputer performance, is hilariously overpowered for the role it plays (in true American fashion). He’s coded the whole thing in the Flame Engine, which is a game engine built on the Flutter UI toolkit by American technology giant Google.

What’s more American than tech giants and fast food? A propane powered plasma cannon, for one thing; or maybe mental gymnastics to translate into freedom units, for another.

Thanks to [Makerinator] for the tip.

A photo of two magnetic bubble memories installed in a circuit board

Scott Baker’s Magnetic Bubble Memory Mega-Post

September 5, 2025 by John Elliot V 11 Comments

Over on his blog our hacker [Scott Baker] has a Magnetic Bubble Memory Mega-Post.

If you haven’t heard of magnetic bubble memory before it’s basically obsolete nonvolatile memory. Since the 1970s when it was introduced this type of memory has been outperformed in every dimension including durability, reliability, price, density, performance, and so on. For any given application of bubble memory you will be able to find an alternative technology which is better in many ways. Except if you want some old tech to geek out over, in that case magnetic bubble memory is for you!

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Restoring A Cheap Fume Hood

September 5, 2025 by Fenix Guthrie 8 Comments

Semiconductor fabrication is complicated requiring nasty chemicals for everything from dopants to etchants. Working with such chemicals at home is dangerous and after releasing hydrochloride acid fumes into his lab, [ProjectsInFlight] decided the time was right to get one for a mere $200.

I can hear the readers down in the comments already saying, “why not just make one?” But a properly engineered fume hood provides laminar flow which absolutely ensures no leakage of fumes out of the hood. However, such proper engineering comes with an impressive price tag, so the used market was the only choice. This is less dangerous then it sounds as companies are required by both OSHA and the EPA to clean their fume hoods before removal, so no chemical residue should remain after purchase.

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Dialing It In: A 3D-Printed Knob With Touchscreen Flair

September 5, 2025 by Matt Varian 34 Comments

Knobs are ubiquitous in technology user interfaces, but touchscreens are increasingly replacing them for interface controls. The latest project from [upir] combines a rotating knob with a touchscreen for a stunning result. The knob-over-display design features a touchscreen where you can place and remove a spinning knob, creating an interface reminiscent of Microsoft’s Surface Dial but at a fraction of the cost.

The core functionality of this device relies on the MT6701 magnetic encoder, which precisely tracks the orientation of the surrounding magnetic field. This encoder is held in place with a 3D-printed jig behind the small touchscreen, hiding the encoder without blocking the magnetic field generated by the magnet above the display. Most circular magnets are axially magnetized, meaning their larger face is one pole. However, diametrically magnetized magnets, where opposite sides of the smaller face are the poles, are used here.

To avoid scratching the screen and ensure smooth turning, [upir] designed a knob that holds the diametrically magnetized magnet slightly above the screen, with a ball bearing connecting the outside of the knob to the center resting on the screen. All the design files needed to recreate this are available on [upir]’s GitHub page; be sure to check them out. Also, browse through our back catalog for other knob-related projects.

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Engineering For Slow Internet Even When Not Stuck In Antarctica

September 5, 2025 by Maya Posch 25 Comments

With the days of dial-up and pitiful 2G data connections long behind most of us, it would seem tempting to stop caring about how much data an end-user is expected to suck down that big and wide broadband tube. This is a problem if your respective tube happens to be a thin straw and you’re located in a base somewhere in the Antarctic. Take it from [Paul Coldren], who was stationed at a number of Antarctic research stations as an IT specialist for a total of 14.5 months starting in August of 2022.

Prepare for hours of pain and retrying downloads. (Credit: Paul Coldren]

As [Paul] describes, the main access to the Internet at these bases is via satellite internet, which effectively are just relay stations. With over a thousand people at a station like McMurdo at certain parts of the season, internet bandwidth is a precious commodity and latency is understandably high.

This low bandwidth scenario led to highly aggravating scenarios, such as when a web app would time out on [Paul] while downloading a 20 MB JavaScript file, simply because things were going too slow. Upon timing out, it would wipe the cache, redirect to an error page and have [Paul] retry and retry to try to squeeze within the timeout window. Instead of just letting the download complete in ~15 minutes, it would take nearly half an hour this way, just so that [Paul] could send a few kB worth of text in a messaging app.

In addition to these artificial timeouts – despite continuing download progress – there’s also the issue of self-updating apps, with a downloader that does not allow you to schedule, pause, resume or do anything else that’d make downloading that massive update somewhat feasible. Another thing here is distributed downloads, such as when hundreds of people at said Antarctic station are all trying to update MacOS simultaneously. Here [Paul] ended up just – painfully and slowly – downloading the entire 12 GB MacOS ISO to distribute it across the station, but a Mac might still try to download a few GB of updates regardless.

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Psst… Got A Second? Here Are The 2025 One-Hertz Challenge Winners

September 5, 2025 by Dan Maloney 20 Comments

Even with teachers with names like Kirchhoff and Helmholtz, old Heinrich Hertz himself likely didn’t have the slightest idea that his name would one day become an SI unit. Less likely still would have been the idea that Hackaday would honor him with the 2025 One-Hertz Challenge.

The challenge was deliberately — dare we say, fiendishly? — simple: Do something, anything, but do it once a second. Flash a light, ring a bell, click a relay, or even spam comments on a website other than Hackaday; anything at all, but do it at as close to one Hertz as possible. These are our favorite kinds of contests, because the simplicity affords a huge canvas for the creative mind to paint upon while still providing an interesting technical constraint that’s just difficult enough to make things spicy.

And boy, did you respond! We’ve received over a hundred entries since we announced the contest back in June, meaning that many of you spent 4,662,000 seconds of your summer (at least those of you above the equator) rising to the challenge. The time was well spent, with projects that pushed the limits of what we even expected.

While we loved ’em all, we had to winnow them down to the top three, each of which receives a $150 gift certificate from our sponsor, DigiKey. Let’s take a look at them, along with our favorite runners-up.

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Hackaday Podcast Episode 336: DIY Datasette, Egg Cracking Machine, And Screwing 3D Prints

September 5, 2025 by Jenny List 1 Comment

Thunderstorms were raging across southern Germany as Elliot Williams was joined by Jenny List for this week’s podcast. The deluge outside didn’t stop the hacks coming though, and we’ve got a healthy smorgasbord for you to snack from. There’s the cutest ever data cassette recorder taking a tiny Olympus dictation machine and re-engineering it with a beautiful case for the Commodore 64, a vastly overcomplex machine for perfectly cracking an egg, the best lightning talk timer Hackaday has ever seen, and a demoscene challenge that eschews a CPU. Then in Quick Hacks we’ve got a QWERTY slider phone, and a self-rowing canoe that comes straight out of Disney’s The Sorcerer’s Apprentice sequence.

For a long time we’ve had a Field guide series covering tech in infrastructure and other public plain sight, and this week’s one dealt with pivot irrigation. A new subject for Jenny who grew up on a farm in a wet country. Then both editors are for once in agreement, over using self-tapping screws to assemble 3D-printed structures. Sit back and enjoy the show!

Want to listen offline? Grab yourself an MP3 hot off the press.