A man in a red plaid shirt draped over an olive t-shirt holds sandpaper in one hand an an aluminum tube filled with white beads in the other over a wooden table.

Activated Alumina For Desiccating Your Filament

June 27, 2024 by 22 Comments

When you first unwrap a shiny new roll of filament for your FDM printer, it typically has a bag of silica gel inside. While great for keeping costs low on the manufacturing side, is silica gel the best solution to keep your filament dry at home?

Frustrated with the consumable nature and fussy handling of silica gel beads, [Build It Make It] sought a more permanent way to keep his filament dry. Already familiar with activated alumina beads, he crafted a desiccant cylinder that can be popped into the oven all at once instead of all that tedious mucking about with emptying and refilling plastic capsules.

A length of aluminum intake pipe, some high temperature epoxy, and aluminum mesh are all combined to make a simple, sealed cylinder. During the process, he found that using a syringe filled with the epoxy led to a much more precise application to the aluminum cylinder, so he recommends starting out that way if you make these for yourself.

We suspect something with a less permanent attachment at one end would let you periodically swap out the beads if you wanted to try this hack with the silica beads you already had. Perhaps some kind of threaded pipe fitting? If you want a more active dryer, try making one with a Peltier. If you want to know just how dry your filament is getting, you could also put in a sensor. You might also wonder, do you really need to dry filament at all?

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Portable, Full-Size Arcade Cabinets

June 27, 2024 by 3 Comments

Believe it or not, there was a time when the only way for many of us to play video games was to grab a roll of quarters and head to the mall. Even though there’s a working computer or video game console in essentially every house now doesn’t mean we don’t look back with a certain nostalgia on those times, though. Some have turned to restoring vintage arcade cabinets and others build their own. This hackerspace got a unique request for a full-sized arcade cabinet that was also easily portable as well.

The original request was for a portable arcade cabinet, and the original designs were for a laptop-like tabletop arcade. But further back-and-forth made it clear they wanted full-size cabinets that just happened to also be portable. So with that criteria in mind the group started building the units. The updated design is modular, allowing the controls, monitor, and Raspberry Pi running the machines to be in self-contained units, with the cabinets in two parts that can quickly be assembled on-site. The base is separate and optional, with the top section capable of being assembled on the base or on something like a tabletop or bar, and the electronics section quickly drops in.

While the idea of a Pi-powered arcade cabinet is certainly nothing new, the quick build, prototyping, design, and final product that’s mobile and quickly assembled are all worth checking out. There is even more information on the build at the project’s GitHub page including Fusion 360 models. If you need your cabinets to be even more portable, this tabletop MAME cabinet is a great place to start.

A Previously Unknown Supplier For A Classic Chip

June 27, 2024 by 7 Comments

It’s common enough for integrated circuits to be available from a range of different suppliers, either as licensed clones, or as reverse-engineered proprietary silicon. In the case of a generic circuit such as a cheap op-amp it matters little whose logo adorns the plastic, but when the part in question is an application processor it assumes much more importance. In the era of the 486 and Pentium there were a host of well-known manufacturers producing those chips, so it’s a surprise decades later to find that there was another, previously unknown. That’s just what [Doc TB] has done though, finding a 486 microprocessor from Shenzhen State Micro. That’s not a brand we ever saw in our desktop computers back in the 1990s.

Analysis of a couple of these chips, a DX33 and a DX2-66, shows them to have very similar micro-architecture but surprisingly a lower power consumption suggesting a smaller fabrication process. There’s the fascinating possibility that these might have been manufactured to serve an ongoing demand for 486 processors in some as-yet-unknown Chinese industrial application, but before any retrocomputer enthusiasts get their hopes up, the chips can’t be found anywhere from Shenzhen State Micro’s successor company. So for now they’re a fascinating oddity for CPU collectors, but who knows, perhaps more information on these unusual chips will surface.

Meanwhile we’ve looked at the 486’s legacy in detail  before, even finding there could still just be 486-compatible SoCs out there.

Powering Airplanes With Microwaves: An Aviation Physics Challenge Amidst Many

June 27, 2024 by 19 Comments

Falling firmly under the fascinating science category of ‘What if…?’ comes the idea of powering airplanes with beamed microwaves. Although the idea isn’t crazy by itself, since we can even keep airplanes flying using just solar power (though with no real useful payload), running through the numbers as [Ian McKay] does in a recent article in IEEE Spectrum makes it clear that there are still some major hurdles if we want to make such a technology reality. Yet is beamed microwave power that much more far out than other alternative ways to power aviation?

Most of the issues are rather hard limits with the assumed technology (phased microwave arrays), with the need for 170 meter diameter ground transmitters every 100 km along the route (including floating transmitters on the oceans with massive power cables, apparently). Due to the limited surface area on something like a Boeing 737-800 you’d need to cram the full take-off power needs (~30 MW) on its ~1,000 m2 surface area available for receiver elements, or 150 Watt per rectifying antenna (rectenna) element assuming a wavelength of 5 cm.

The good news is that the passengers inside would probably survive if the microwave-like shielding keeps up, and birds passing through the beams are likely to survive if they’re fast enough. It’d ruin a whole part of the local radio spectrum from leaked microwaves, of course. Unfortunately beaming MW levels of microwaves across 100 km is still beyond our capabilities.

After this fun science session, [Ian] then looks at alternatives like batteries and hydrogen, neither of which come even close to the energy density (or relative safety) of commercial aviation fuels. Perhaps synthetic aviation fuel might be the ticket, but at this point beamed microwave power is as likely to replace aviation fuel as batteries or hydrogen, though more likely than countries like the United States building out a fast & cheap high-speed rail network.

The SS United States: The Most Important Ocean Liner We May Soon Lose Forever

June 27, 2024 by 14 Comments

Although it’s often said that the era of ocean liners came to an end by the 1950s with the rise of commercial aviation, reality isn’t quite that clear-cut. Coming out of the troubled 1940s arose a new kind of ocean liner, one using cutting-edge materials and propulsion, with hybrid civil and military use as the default, leading to a range of fascinating design decisions. This was the context in which the SS United States was born, with the beating heart of the US’ fastest battle ships, with light-weight aluminium structures and survivability built into every single aspect of its design.

Outpacing the super-fast Iowa-class battleships with whom it shares a lot of DNA due to its lack of heavy armor and triple 16″ turrets, it easily became the fastest ocean liner, setting speed records that took decades to be beaten by other ocean-going vessels, though no ocean liner ever truly did beat it on speed or comfort. Tricked out in the most tasteful non-flammable 1950s art and decorations imaginable, it would still be the fastest and most comfortable way to cross the Atlantic today. Unfortunately ocean liners are no longer considered a way to travel in this era of commercial aviation, leading to the SS United States and kin finding themselves either scrapped, or stuck in limbo.

In the case of the SS United States, so far it has managed to escape the cutting torch, but while in limbo many of its fittings were sold off at auction, and the conservation group which is in possession of the ship is desperately looking for a way to fund the restoration. Most recently, the owner of the pier where the ship is moored in Philadelphia got the ship’s eviction approved by a judge, leading to very tough choices to be made by September.

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LEGO Bricks: Now Out Of This World

June 27, 2024 by 15 Comments

Now the eyes of space explorers are turned once more towards the Moon, there are a whole host of new engineering challenges facing engineers working on lunar missions. One such challenge relates to how any proposed Moon base might be built, and as European Space Agency (ESA) researchers turn their mind to the problem they’ve taken a uniquely European approach. They’ve made some LEGO bricks.

Sadly lunar regolith is in short supply in Europe at the moment, so as a stand-in they’ve ground up a meteorite, mixed the powder with a polymer, and 3D printed their bricks. The LEGO write-up is a little long on frothy writing style and a little short on the science, but it seems that they clutch in exactly the same way as the official bricks from Billund, and can be assembled just as you would a normal set of bricks.

It’s with some regret that we have to concede that Europe’s off-planet outpost won’t be crewed by LEGO people in a base made from LEGO bricks, but we applaud them for doing this as a practical test given the limited supply of starter material. LEGO themselves have snagged some of them to display in a range of their flagship stores, so we hot-footed it down to London to catch some pictures. What we found is a single brick in a glass case, sadly looking very like any other 3D printed brick in a shiny grey medium. It’s probably the most expensive brick in the world though, so we doubt they’ll be available to buy any time soon.

If you’re hungry for more of all things LEGO, we can do no better than suggest a trip to the mother lode, in Billund, Denmark.

Enjoy Totality Every Day With This Personal Eclipse Generator

June 27, 2024 by 29 Comments

There have been a couple of high-profile solar eclipses lately, but like us, you probably missed the news of the one that passed over Munich in 2019. And every day since then, in fact, unless you were sitting in a particular spot: the couch of one [Bernd Kraus], who has his very own personal eclipse generator.

We’ll attempt to explain. Living in an apartment with a gorgeous western view of Munich is not without its cons, chief among which is the unobstructed exposure to the setting sun. Where most people would opt for a window treatment of some sort to mitigate this, [Bernd] felt that blotting out the entire view was a heavy-handed solution to the problem. His solution is a window-mounted X-Y gantry that dangles a cutout of the moon in just the right place to blot out the sun. An Arduino uses the time and date to calculate the position of the sun as it traverses the expansive window and moves the stepper motors to keep the moon casting its shadow in just the right place: on his face as he sits in his favorite spot on the couch.

There are a couple of time-lapse sequences in the video below, as well as a few shots of the hardware. We know this isn’t an actual coronagraph, but the effect is pretty cool, and does resemble an eclipse, at least in spirit. And it goes without saying that we applaud the unnecessary complexity embodied by this solution.

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