The clock and the rebuilt calculator from which its VFD was donated.

An RPN Calculator And A Bonus VFD Clock From Casio Revival

Have you heard the saying “the problem is the solution”? It seems to originate in the permaculture movement, but it can apply equally well to electronics. Take the problem [shiura] had: a Casio Mini CM-602 that had let out the magic smoke. The solution was a twofer: rebuild the Casio into a modern number cruncher with Reverse Polish Notation (RPN), and save the Vacuum Fluorescent Display (VFD) for a gorgeous WiFi clock.

[shiura]’s write-up includes a helpful guide for reverse engineering the pins on this sort of VFD, if you don’t happen to have the same model calculator (or VFD tube) they’re working with. If you’ve done this sort of thing, you know what to expect: power it up and kill power to the pins, one by one, to map out which segments or characters go out, thereby identifying the anodes and grid electrodes. The cathodes had already been ID’d from looking at the PCB. After that it’s just a matter of wiring the VFD to an ESP32 via a transistor array to get the voltages right, and voila! Clock. The code and case design files for this clock — including an editable .blend — are available via GitHub.

The calculator half of the project is an incredibly elegant hack that relies on the fact that the Casio’s CPU has the same pin pitch as modern micros: 2.54 mm, or 0.1″, so an RP2040 zero can sit in the footprint of the original CPU, scanning the keypads with its GPIO. Then an I2C display is separately wired up to replace the clockified VFD. Perhaps some driver circuitry for the VFD died, or [shiura] salvaged the display before deciding to save the calculator, because otherwise we see no reason why this brain transplant couldn’t be done while keeping the original display. Admittedly having two lines on the display instead of one make the “new” calculator a tad more usable. The code for that is also available on GitHub, and while the readme is in Japanese, machine translations have gotten pretty good and the code is quite readable on its own.

Longtime readers will likely be familiar with [shiura]’s work, with a number of finely crafted clocks having been featured from the Japanese maker, along with vintage pocket computer repairs. Bringing both together makes this twin hack particularly on-brand.

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[Mark] shows off footage from a D1 master on the repaired deck

Reviving ReBoot With A Tape Deck Repair

Do you remember ReBoot? If you were into early CGI, the name probably rings a bell, since when it premiered in 1994 it was the first fully computer-animated show on TV. Some time ago, a group found a pile of tapes from Mainframe Studios in Canada, the people behind ReBoot, and the computer historians amongst us were very excited… until they turned out to be digital broadcast master tapes. Exciting for fans of lost media, sure, but not quite the LTO backups of Mainframe’s SGI workstations some of us had hoped would turn up. Still, [Mark Westhaver], [Bryan Baker] and others at the “ReBoot Rewind” project have made great strides, to the point that in their latest update video they declare “We Saved ReBoot

What does it take to revive a 30-year-old television project? Well, as stated, they started with the tapes. These aren’t ordinary VHS tapes: the Sony D-1 tapes, which were also known by the moniker “4:2:2”, are a format that most people who didn’t work in the TV or film industry will have never seen, and the tape decks are rare as hen’s teeth these days. Just getting a working one, and keeping it working, was one of the biggest challenges [Mark] and Reboot Rewind faced. In the end it took three somewhat-dodgy machines long past their service lives and a miraculously located spare read/write head to get a stable scanning rate.

The uncompressed digital output of these tapes isn’t something you can just burn to a DVD, either. The 720 × 576 resolution video stream is captured raw, but there are minor editing tweaks that need to be made in addition to tape errors that have cropped up over the years, and those need to be dealt with before the video and audio data gets encoded into a modern format. The video briefly glosses [Bryan Baker]’s workflow to do just that. At least they aren’t stuck with terrible USB video capture dongles VHS lovers have to deal with. Even if you don’t care about ReBoot, this isn’t the only show that was archived on D1 tapes so that workflow might be of interest to media fans.

We covered ReBoot Rewind when they were first searching for tape decks, so it’s great to have an update. Alas, the rights holders haven’t yet decided how exactly they’re going to release this fine footage, so if like this author you have fond memories of ReBoot, you may have to wait a bit longer for a reWatch.

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Sleeping Rough In Alaska With A USPS Cargo Bike

Out of all 49 beautiful US states (plus New Jersey), the one you’d probably least want to camp outside in during the winter is arguably Alaska. If you were to spend a night camping out in the Alaskan winter, your first choice of shelter almost certainly wouldn’t be a USPS electric cargo trike, but over on YouTube [Matt Spears] shows that it’s not that hard to make a lovely little camper out of the mail bike. 

We’re not sure how much use these sorts of cargo trikes get in Alaska, but [Matt] seems to have acquired this one surplus after an entirely-predictable crash took one of the mirrors off. A delta configuration trike — single wheel in front — is tippy at the best of times, but the high center of gravity you’d get from a loading the rear with mail just makes it worse. That evidently did not deter the United States Postal Service, and it didn’t deter [Matt] either.

His conversion is rather minimal: to turn the cargo compartment into a camper, he only adds a few lights, a latch on the inside of the rear door, and a wood-burning stove for heat. Rather than have heavy insulation shrink the already-small cargo compartment, [Matt] opts to insulate himself with a pile of warm sleeping bags. Some zip-tie tire chains even let him get the bike moving (slowly) in a winter storm that he claims got his truck stuck.

While it might not be a practical winter vehicle, at least on un-plowed mountain roads, starting with an electric-assist cargo trike Uncle Sam already paid for represented a huge cost and time savings vs starting from scratch like this teardrop bike camper we featured a while back. While not as luxurious, it seems more practical for off-roading than another electric RV we’ve seen.

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Pickle Diodes, Asymmetric Jacobs Ladders, And Other AC Surprises

While we’re 100 years past Edison’s fear, uncertainty, and doubt campaign, the fact of the matter is that DC is a bit easier to wrap one’s head around. It’s just so honest in its directness. AC, though? It can be a little shifty, and that results in some unexpected behaviors, as seen in this video from [The Action Lab].

He starts off with a very relatable observation: have you ever noticed that when you plug in a pickle, only half of it lights up? What’s up with that? Well, it’s related to the asymmetry he sees on his Jacobs ladder that has one side grow hotter than the other. In fact, it goes back to something welders who use DC know about well: the Debye sheath.

The arc of a welder, or a Jacobs ladder, or a pickle lamp is a plasma: ions and free electrons. Whichever electrode has negative is going to repel the plasma’s electrons, resulting in a sheath of positive charge around it. This positively-charged ions in the Debye sheath are going to accelerate into the anode, and voila! Heating. That’s why it matters which way the current goes when you’re welding.

With DC, that makes sense. In AC, well — one side starts as negatively charged, and that’s all it takes. It heats preferentially by creating a temporary Debye sheath. The hotter electrode is going to preferentially give off electrons compared to its colder twin — which amplifies the effect every time it swings back to negative. It seems like there’s no way to get a pure AC waveform across a plasma; there’s a positive feedback loop at whatever electrode starts negative that wants to introduce a DC bias. That’s most dramatically demonstrated with a pickle: it lights up on the preferentially heated side, showing the DC bias. Technically, that makes the infamous electric pickle a diode. We suspect the same thing would happen in a hot dog, which gives us the idea for the tastiest bridge rectifier. Nobody tell OSHA.

[The Action Lab] explains in more detail in his video, and demonstrates with ring-shaped electrode how geometry can introduce its own bias. For those of us who spend most of our time slinging solder in low-voltage DC applications, this sort of thing is fascinating.  It might be old hat to others here; if the science of a plain Jacobs ladder no longer excites you, maybe you’d find it more electrifying built into a blade.

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The solar-electric tractor is out standing in its field.

Adding Solar Power To An Electric Tractor

In my country, we have a saying: the sun is a deadly lazer. Well, it’s not so much a folk saying as a meme, and not so much in one country as “the internet”. In any case, [LiamTronix] was feeling those cancer rays this harvest season when running his electric tractor, and realized that– since he’s already charging it with ground-mounted solar panels anyway–if he’s going to build a roof for his ride, he might as well make charge the batteries.

Another bonus is safety: the old Massey-Ferguson at the heart of the electric tractor build didn’t come with any rollover protection from the factory back in the 1960s. Since having however many tons of tractor roll onto you was bad enough before it got a big hefty battery pack, we heartily approve of including a roll cage in this build. Speaking of battery packs, he’s taking this chance to upgrade to a larger LiFePo pack from the LiIon pack he installed when we first featured this conversion in 2024.

Atop the new roll cage, and above the new battery, [Liam] installed four second-hand 225 W solar panels. Since that’s under 1kW even if the panels have not degraded, the tractor isn’t going to be getting much charge as it runs. In the northern winter, [Liam] is only able to pull 80 W from the set. That’s not getting much work done, but who wants a tractor without a cab or heater when it’s below freezing? In the summer it’s a much better story, and [Liam] estimates that the roof-mounted panels should provide all of the energy needed to run the tractor for the couple hours a day he expects to use it.

If you’re wondering how practical all this is, yes, it can farm  — we covered [Liam] putting the project through its paces in early 2025.

The big white thing is is the CO2 exhaust bag.

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

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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Welded frame and cylinders for T1 #5550

Building A Steam Loco These Days Is Nothing But Hacks

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.

Right now, if donations continue to trickle in at the current rate– and prices don’t rise any faster than they have been– the Trust hopes to have the locomotive steaming in 2030. She’s now 59.8% complete. That’s up from 40% when we last checked in, back in 2022, which is great progress considering this is a volunteer-driven, crowd-funded effort.

If you don’t have the skills or geographical location to volunteer with this build, but we’ve piqued your love of steam, perhaps you could 3D print an engine to scratch the itch.

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