PLA mail being tested against a sword

3D Printed Mail Is A Modern Solution To An Ancient Problem

The human body and sharp objects don’t get along very well, especially when they are being wielded with ill-intent. Since antiquity there have been various forms of armor designed to protect the wearer, but thankfully these days random sword fights don’t often break out on the street. Still, [SCREEN TESTED] wanted to test the viability of 3D printed chain mail — if not for actual combat, at least for re-enactment purposes.

He uses tough PLA to crank out a bed worth of what looks like [ZeroAlligator]’s PipeLink Chainmail Fabric, which just so happens to be the trending result on Bambu’s MakerWorld currently. The video shows several types of mail on the printer, but the test dummy only gets the one H-type pattern, which is a pity — there’s a whole realm of tests waiting to be done on different mail patterns and filament types.

In any case, the mail holds up fairly well to puncture from scissors and screwdrivers — with a heavy sweater or proper gambeson (a quilted cloth underlayer commonly worn with armor) on underneath, it looks like it could actually protect you. To slashing blows, PLA holds up astoundingly well, barely marked even by slashes from an actual sword. As for projectiles, well, everyone knows that to an arrow, chain mail is made of holes, and this PLA-based armor is no different (as you can see at 8:30 in the video below).

If you want to be really safe when the world goes Mad Max, you’d probably want actual chain mail, perhaps from stainless steel. On the other hand, if someone tries to mug you on the way home from a con, cosplay armor might actually keep you safer than one might first suspect. It’s not great armor, but it’s a great result for homemade plastic armor.

Of course you’d still be better off with Stepahnie Kwolek’s great invention, Kevlar.

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A photo of some drives with their controller boards

Installing An 84MB Hard Drive Into A PDP-11/44

Over on YouTube [Usagi Electric] shows us how he installed an 84MB hard drive into his PDP-11/44.

In the beginning he purchased a bunch of RA70 and RA72 drives and board sets but none of them worked. As there are no schematics it’s very difficult to figure out how they’re broken and how to troubleshoot them.

Fortunately his friend sent him an “unhealthy” Memorex 214 84MB hard drive, also known as a Fujitsu 2312. The best thing about this hard drive is that it comes complete with a 400 page manual which includes the full theory of operation and a full set of schematics. Score!

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Cheap Multimeter Gets Webified

[Mellow Labs] wanted to grab a multimeter that could do Bluetooth. Those are cheap and plentiful, but the Bluetooth software was, unsurprisingly, somewhat lacking. A teardown shows a stock Bluetooth module. A quick search found a GitHub with software. But then he had a fiendish idea: could you replace the Bluetooth module with an ESP32 and use WiFi instead of Bluetooth?

This was as good an excuse as any to buy a cheap logic analyzer. Armed with some logic captures, it was easy to figure out how to fake the meter into thinking a Bluetooth client was connected.

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FLOSS Weekly Episode 854: The Big Daddy Core

This week Jonathan and Ben chat with Jason Shepherd about Ocre and Atym.io! That’s the lightweight WebAssembly VM that lets you run the same containers on Linux and a host of embedded platforms, on top of the Zephyr embedded OS. What was the spark that led to this project’s creation, what does Atym.io bring to the equation, and what are people actually doing with it? Watch to find out!

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Radio Apocalypse: Survivable Low-Frequency Communication System

In the global game of nuclear brinksmanship, secrets are the coin of the realm. This was especially true during the Cold War, when each side fielded armies of spies to ferret out what the other guy was up to, what their capabilities were, and how they planned to put them into action should the time come. Vast amounts of blood and treasure were expended, and as distasteful as the whole thing may be, at least it kept armageddon at bay.

But secrets sometimes work at cross-purposes to one’s goals, especially when one of those goals is deterrence. The whole idea behind mutually assured destruction, or MAD, was the certain knowledge that swift retaliation would follow any attempt at a nuclear first strike. That meant each side had to have confidence in the deadliness of the other’s capabilities, not only in terms of their warheads and their delivery platforms, but also in the systems that controlled and directed their use. One tiny gap in the systems used to transmit launch orders could spell the difference between atomic annihilation and at least the semblance of peace.

During the height of the Cold War, the aptly named Survivable Low-Frequency Communication System was a key part of the United States’ nuclear deterrence. Along with GWEN, HFGCS, and ERCS, SLFCS was part of the alphabet soup of radio systems designed to make sure the bombs got dropped, one way or another.

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Morse Code For China

It is well known that pictographic languages that use Hanzi, like Mandarin, are difficult to work with for computer input and output devices. After all, each character is a tiny picture that represents an entire word, not just a sound. But did you ever wonder how China used telegraphy? We’ll admit, we had not thought about that until we ran into [Julesy]’s video on the subject that you can watch below.

There are about 50,000 symbols, so having a bunch of dots and dashes wasn’t really practical. Even if you designed it, who could learn it? Turns out, like most languages, you only need about 10,000 words to communicate. A telegraph company in Denmark hired an astronomer who knew some Chinese and tasked him with developing the code. In a straightforward way, he decided to encode each word from a dictionary of up to 10,000 with a unique four-digit number.

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Wayland’s Never-Ending Opposition To Multi-Window Positioning

There are many applications out there that use more than one window, with every modern-day platform and GUI toolkit offering the means for said application to position each of its windows exactly where it wants, and to restore these exactly in the configuration and location where the user saved it for that particular session. All toolkits but one, that is, for the Wayland project keeps shooting down proposals. Most recently merge request #264 for the ext-zones protocol by [Matthias Klumpp] as it descended into a 600+ comments spree.

This follows on an attempt two years prior with MR#247, which was rejected despite laying out sound reasons why the session protocol of Wayland does not cover many situations. In the breakdown video of the new ext-zones protocol discussion by [Brodie Robertson] the sheer absurdity of this whole situation becomes apparent, especially since KDE and others are already working around the Wayland project with their own extensions such as via KWin, which is being used commercially in e.g. the automotive world.

In a January 2024 blog post [Matthias] lays out many of his reasonings and views regarding the topic, with a focus on Linux desktop application usage from a scientific application perspective. When porting a Windows-, X11- or MacOS application to Wayland runs into compatibility issues that may necessitate a complete rewrite or dropping of features, the developer is more likely to stick to X11, to not port to Linux at all, or to use what eventually will amount to Wayland forks that patch around these missing API features.

Meanwhile X11 is definitely getting very long in the tooth, yet without it being a clean drop-in replacement it leaves many developers and end-users less than impressed. Perhaps the Wayland project should focus more on the needs of developers and end-users, and less about what it deems to be the One True Way?

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