Mysterious Files PH

As common as the Xbox 360 was, the development kits (XDKs) for these consoles are significantly less so. This makes it even more tragic when someone performs a botched surgery on one of these rare machines, leaving it in dire straits. Fortunately [Josh Davidson] was able to repair the XDK in question for a customer, although it entailed replacing the GPU, CPU and fixing many traces.

The Xbox 360 Development Kit is effectively a special version of the consumer console — with extra RAM and features that make debugging software on the unit much easier, such as through direct access to RAM contents. They come in a variety of hardware specifications that developed along with the game console during its lifecycle, with this particular XDK getting an upgrade to being a Super Devkit with fewer hardware restrictions.

Replacing the dead GPU was a new old stock Kronos 1 chip. Fortunately the pads were fine underneath the old GPU, making it easy to replace. After that various ripped-off pads and traces were discovered underneath the PCB, all of which had to be painstakingly repaired. Following this the CPU had apparently suffered heat damage and was replaced with a better CPU, putting this XDK back into service.

We are going to bet that as a kid, you had a View-Master. This toy has been around for decades and is, more or less, a handheld stereoscope. We never thought much about the device’s invention until we saw a recent video from [View Master Travels and Peter Dibble]. It turns out that the principle of the whole thing was created by the well-known [Charles Wheatstone]. However, it was piano repairman [William Gruber] who invented what we think of as the View-Master.

[Gruber] didn’t just work on normal pianos, but complex player pianos and, in particular, the pianos used to record player piano rolls. He was also, as you might expect, a stereo photography enthusiast. Many of the ideas used in automating pianos would show up in the View-Master and the machines that made the reels, too. In the 1930s, stereoscopes were not particularly popular and were cumbersome to use. Color film was also a new technology.

[Gruber] realized that a disk-like format would be easy to use and, more importantly, easy to mass produce. The reels had a few features to simplify their use. For example, if you show each image in sequence, you’d eventually see pictures upside down. [Gruber’s] solution? Use an odd number of pairs and advance the reel two positions for each jump forward. That way, you never show an image to the wrong eye.

The model “A” didn’t look much like the View-Master you probably remember. By 1940, the toy was a hit. But initially, it wasn’t really a toy so much as a way for adults to view distant sites. Of course, World War II could have stopped the enterprise dead, but instead, they shifted to producing training aids for the military. The War Department would buy 100,000 viewers and about 6 million reels to help train soldiers to identify aircraft and ships, as well as to estimate range.

Training was always a key use of the View-Master technology, but the company eventually bought a competitor with rights to Disney films and exploded into a must-have toy. When the company was bought by GAF, the focus on the toy market grew. Despite some efforts to keep the company relevant in an era with virtual reality and other 3D technologies, View-Master is, sadly, a bit of nostalgia now, even though you can still buy them. But it is impressive that despite many changes to the viewer and the production methods, the View-Master reel remained virtually unchanged despite the production of about 1.5 billion of them. Sure, there were fancy viewers that had audio tracks, too, but the basic idea of an odd number of film frames mounted in a circle in a notched disk remained the same.

These days, a phone can be your View-Master, at least, if you can cross your eyes. Want to preserve your View-Master reels for posterity? So did [W. Jason Altice].

Thermoforming is the process of softening a material enough so that it can be tweaked into a new shape, with the source of the thermal energy being not particularly relevant. Correspondingly, after [Zion Brock]’s recent video on his journey into thermoforming PLA with a mold and a heat gun, he got many comments suggesting that he should use hot water instead.

We covered his previous video as well, in which he goes through the design steps of making these grilles for a retro-styled, 3D printed radio. The thermoforming method enables him to shape the curvy grille with a heat gun and two-piece mold in a matter of minutes, rather than spending hours more time printing and removing many supports.

Theoretically using hot water instead of hot air would provide a more equal application of heat, but putting your hands into 70°C water does require some more precautions. There’s also the issue that PLA is very hygroscopic, so the part requires drying afterwards to prevent accelerated hydrolysis. Due to the more even heating, the edge of the PLA that clamped into the mold also softened significantly, causing it to pop out of the mold and requiring a small design modification to prevent this.

Basically, aqua-thermoforming like this has many advantages, as its slower and more consistent, but it’s less straightforward to use than hot air. This makes both a useful tool when you’re looking at doing thermoforming.

Here’s the Hackaday Europe 2026 announcement that you’ve all been waiting for. But wait! This year there’s a twist, or rather two. What absolutely hasn’t changed, though, is that we’d love to see you there, and we’d love to hear about what you’ve been up to, so get your talk or workshop proposal in before March 18th.

New Place, New Time

Hackaday Europe is moving in all four dimensions! We’ll be meeting up in the absolutely lovely Lecco, Italy — just about equidistant from Milan and Bergamot, and taking place May 16th and 17th, with the traditional pre-event meetup on the night of the 15th for those who are already in town. The location is the Politecnico Milano campus, a hub of engineering nestled in the mountains.

Who is going to be speaking at Hackaday Europe? You could be! We’re opening up the Call for Participation right now, both for talks and for workshops. Whether you’ve presented your work live before or not, you’re not likely to find a more appreciative audience for epic hacks, creative constructions, or you own tales of hardware, firmware, or software derring-do.

Workshop space is limited, but if you want to teach a group of ten or so people your favorite techniques, we’d love to hear from you.

All presenters get in free, of course, so firm up what you’d like to share, and get your proposal submitted ASAP.

The Badge

We’ll be bringing the 2025 Hackaday Supercon Communicator Badge with us to Europe, so this is also your chance to get your hands on the retro-styled super sexy keyboard, LoRa module, and fantastically oblong screen. At Supercon, we ran our own custom mesh network, and it worked flawlessly, even on microwatts. We’ll be continuing the experiment in Italy, on different frequencies of course, but maybe pushing some of the transmission parameters to see how far we can go.

The user side of the badge is very accessible as well, being programmed in Micropython and supported with a sweet plug-in architecture that makes adding your own apps a breeze, or at least reasonably straightforward. And when Hackaday Europe comes to a close, you can simply reflash the badge with new firmware, and you’ve got the sweetest Meshtastic device out there.

And it wouldn’t be a Hackaday badge if it weren’t meant to be modified.

The People

The real reason to come to Hackaday Europe, though, is the other folks who come to Hackaday Europe. You’ve never seen a more interested group of hardware hackers, and that’s coincidentally also why you’d like to give a presentation. You get to tell everyone what you’re up to — it’s the ultimate ice-breaker.

At the risk of saying it again: Get your proposal in before March 18th, and we look forward to seeing you on the shore of Lake Como. (Info on tickets and more pre-conference hype coming soon.)

Ever wanted to know how engineers made their calculations before digital calculators were on every workbench? [Richard Carpenter] and [Robert Wolf] have just the thing—a sliderule simulator that can teach you how to do a whole bunch of complex calculations the old fashioned way!

The simulator is a digital recreation of the Hemmi/Post 1460 Versalog slide rule. This was a particularly capable tool that was sold from 1951 to 1975 and is widely regarded as one of the best slide rules ever made. It can do all kinds of useful calculations for you just by sliding the scales and the cursor appropriately, from square roots to trigonometry to exponents and even multi-stage multiplication and divisions.

You can try the simulator yourself in a full-screen window here. It’s written in JavaScript and runs entirely in the browser. If you’ve never used a slide rule before, you might be lost as you drag the center slide and cursor around. Fear not, though. The simulator actually shows you how to use it. You can tap in an equation, and the simulator will both spit out a list of instructions to perform the calculation and animate it on the slide rule itself. There are even a list of “lessons” and “tests” that will teach you how to use the device and see if you’ve got the techniques down pat. It’s the sort of educational tool that would have been a great boon to budding engineers in the mid-20th century. With that said, most of them managed to figure it out with the paper manuals on their own, anyway.

We’ve featured other guides on how to use this beautiful, if archaic calculation technology, too. We love to see this sort of thing, so don’t hesitate to notify the tipsline if you’ve found a way to bring the slide rule back to relevance in the modern era!

Thanks to [Stephen Walters] for the tip!

Despite the best efforts of the manufacturers, there are folks out there that try to repair power tools, with [Dean Doherty] being one of them. Recently he got a Milwaukee M18 cordless planer in for repairs, which started off with just replacing some dodgy bearings, but ended up with diagnosing a faulty controller. Consequently the total repair costs went up from reasonable to absolutely unreasonable, leading to a rant on why Milwaukee tools are terrible to repair.

Among the symptoms was the deep-discharged battery, which had just a hair over 7 V while unloaded. Question was what had drained the battery so severely. What was clear was that the tool was completely seized after inserting a working battery with just a sad high-pitched whine from a stalled motor.

After replacing both bearings and grumbling about cheap bearings, the tool had a lot of drywall dust cleaned out and was reassembled for a test run. This sadly showed that the controller board had been destroyed due to the seized rotor bearing, explaining the drained battery. Replacing the controller would have cost €60-70 as it comes with the entire handle assembly, rendering the repair non-viable and a waste.

Perhaps the one lesson from this story is that you may as well preventively swap the cheap bearings in your Milwaukee tools, to prevent seizing and taking out the controller board. That said, we’d love to see an autopsy on this controller board fault.

Thanks to [paulvdh] for the tip.

Today, we take ice for granted. But having ice produced in your home is a relatively modern luxury. As early as 1750 BC, ancient people would find ice on mountains or in cold areas and would harvest it. They’d store it, often underground, with as much insulation as they could produce given their level of technology.

By 500 BC, people around Egypt and what is now India would place water in porous clay pots on beds of straw when the night was cold and dry. Even if the temperature didn’t freeze, the combination of evaporation and radiative cooling could produce some ice. However, this was elevated to a high art form around 400 BC by the Persians, who clearly had a better understanding of physics and thermodynamics than you’d think.

The key to Persian icemaking was yakhchāls. Not all of them were the same, but they typically consisted of an underground pit with a conical chimney structure. In addition, they often had shade walls and ice pits as well as access to a water supply.

Solar Chimney

The conical shape optimizes the solar chimney effect, where the sun heats air, which then rises. The top was typically not open, although there is some thought that translucent marble may have plugged the top to admit light while blocking airflow. yakhchālThe solar chimney produces an updraft that tends to cool the interior. The underground portion of the yakhchāl has colder air, as any hot air rises above the surface.

Insulation and Shade

The structure uses a water-resistant mortar made of sand, clay, egg whites, lime, goat hair, and ash. This has good insulating properties, although how the Persians found this recipe is a mystery. Many also had windcatcher towers that allowed for evaporative cooling in the dry air.

Adjacent to the yakhchāl was often a shallow ice pool protected by a shade wall to block the sun. The shade wall minimized heating from the sun. Just as the Egyptians leveraged evaporative and radiative cooling to create ice, cold nights could produce ice in the pool, which workers would harvest and store inside the yakhchāl. They could also, of course, store ice harvested from elsewhere. Even with the shade wall, though, workers had to harvest ice before sunrise.

You could think of the whole system as an RC circuit. The dome and the soil around the pit form a resistance, while the ice, cold stone, and air inside form a thermal capacitor. Thick insulating walls make a large R, and tons of ice and stone make a big capacitor. The dome shape gets less solar radiation most of the time. With a big resistor and capacitor, bleeding off charge (in this case, leaking in heat) takes a long time.

Meanwhile, ice melting effectively absorbs leftover or leaking heat. Sure, you lose some ice, although with the ice pits, on a cold and dry night, you might be able to recover at least some of it.

Why?

The Persians wanted ice for the same reasons everyone else did. They preserved food, created frozen beverages (sharbat), and even a dessert, faloodeh, that combined noodles, rose syrup, lime, and ice. There were also medical uses. Of course, having ice in the hot desert was also a status symbol.

Other Tech

In China, around 600 AD, they used saltpeter to produce ice chemically instead of simply harvesting and storing it. It would be 1748 before [William Cullen] would demonstrate producing ice using artificial means. While [Oliver Evans] described a fairly modern refrigerator in 1805, nothing like it was built until [Jacob Perkins] did it in 1834. Australian [James Harrison] was probably the first commercial ice makaer in the mid 1800s.

These days, we don’t usually ship ice around, but we still have to ship cold things. And of course, refrigerators ended the ice harvesting business.

Featured image: “kosar” by [Elyaskb]