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Hackaday Links: July 14, 2024

July 14, 2024 by 11 Comments

We’ve been going on at length in this space about the death spiral that AM radio seems to be in, particularly in the automotive setting. Car makers have begun the process of phasing AM out of their infotainment systems, ostensibly due to its essential incompatibility with the electronics in newer vehicles, especially EVs. That argument always seemed a little specious to us, since the US has an entire bureaucracy dedicated to making sure everyone works and plays well with each other on the electromagnetic spectrum. The effort to drop AM resulted in pushback from US lawmakers, who threatened legislation to ensure every vehicle has the ability to receive AM broadcasts, on the grounds of its utility in a crisis and that we’ve spent billions ensuring that 80% of the population is within range of an AM station.

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Five Ways To Repair Broken PCB Traces

July 14, 2024 by 23 Comments

When everything used wires, it was easy to splice them or replace them. Not so much with PC boards, but everyone has their favorite method for repairing a broken trace. [Mr. SolderFix] has his five favorite ways, as you can see in the video below.

Of course, before you can repair a trace, you probably have to expose it since most boards have solder mask now. Unless you plan to shut the trace at both ends, exposing the actual trace is probably the first step.

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The Mysterious Roman Dodecahedron Was Possibly Just For Knitting

July 14, 2024 by 38 Comments

Over the years archaeological digs of Roman sites have uncovered many of these strange dodecahedrons, usually made out of metal and with various holes in their faces. With no surviving records that describe how they were used, speculation has ranged from jewelry to a knitting aid. In a 2023 video by [Amy Gaines] it is this latter use which is explored, using a 3D printed dodecahedron and some wooden dowels to knit both gold wire and yarn into rather intricate patterns that are also referred to as ‘Viking Knitting’.

As we mentioned previously when yet another one of these dodecahedrons was uncovered, their use was unlikely to be of supreme relevance in military or scientific circles on account of a lack of evidence. What is quite possible is that these were both attractive shapes for jewelry (beads), and useful knitting aids for both jewelry makers (for e.g. gold wire braiding) and quite possibly yarn-related uses. The results which [Amy] demonstrates in the video for the gold wire in particular bear a striking resemblance to ancient braided gold chains on display at the Met and other museums, which leads credence to this theory.

If these items were effectively just common knitting tools, that would explain why the historical record is mum on them, as they would have been as notable as a hammer or a precision lathe used by the ancient Greeks.

Thanks to [john] for the tip.

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Print Wave Metal Casting

July 13, 2024 by 4 Comments

Direct 3D printing of metal remains out of reach for the hobbyist at the moment, so casting is often the next best thing, particularly given the limitations of 3D printed metals. [Denny] from Shake the Future shows us how to simplify the process with “print wave metal casting.”

The first step of printing a PLA object will seem familiar to any 3D print to metal process, but the main differentiator here is pouring the investment casting on the printer build plate itself. We like how he used some G-code to shake the build plate to help remove bubbles. Once the plaster solidifies, the plastic and mold are placed in the microwave to soften the plastic for removal.

The plaster is dried in an oven (or air fryer) and then [Denny] bolts the mold together for the casting process. Adding a vacuum helps with the surface finish, but you can always polish the metal with a generous helping of elbow grease.

If [Denny] seems familiar, you might remember his very detailed breakdown of microwave casting. We’ve seen plenty of different approaches to metal casting over the years here. Need a part in another material? How about casting concrete or resin?

Thanks to [marble] on the Hackaday Discord for the tip!

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It’s Not Unusual To Love Hacking

July 13, 2024 by 21 Comments

Most of what we do here at Hackaday is look out for cool projects and then write them up so that you all know about them. Nothing is better than being really stoked about a clever hack and then being able to share it with tens of thousands of like-minded folks. Sure, it’s our job, but we really do it because we love to share. And it’s clear that you all do too! After all, we write up the hacks that you document for us.

We recently featured a hack where the guy who did the work in question said that he didn’t think it was “worthy of Hackaday”. (Of course, it was!) And I don’t like that sentiment at all, honestly, because a hack that you enjoyed doing is a hack worth sharing, even if just for sharing the joy of doing it, and that came across fully.

Of course we gladly feature the ultra-bravado hacks where the nearly impossible is made real. But there’s equal value in the simple hacks that inspire others to pursue one odd path or another. Or even pieces where there’s no hack involved, but simply the sharing of something cool.

This week, [Arya Voronova] wrote a piece about her experience using MicroPython on embedded devices, and it apparently resonated with a lot of our readers. It’s not a deep-dive into MicroPython, or a mind-bending abuse of the language. Instead, it’s a simple “this is what I love about doing things this way”, and that’s a great perspective that often gets lost when we get deep in the technical weeds.

I had the same realization a few months back at Hackaday Europe. In the lightning talks, most everyone gave talks about cool projects that they are working on, and they’re absolutely worth watching for that. [Jaap Meijers] gave a wonderful talk about making animated QR codes, but it wasn’t about how he invented animated QR codes, because he was just using someone else’s project. Instead, it was about how neat he thought someone else’s work was, and how he really wanted to share it with us. (And now you know too.)

Epic hacks are fantastic, no question. But the simple expression of the love of hacking, whether in words or in the doing, is equally important. Show us your work, but don’t forget to show us your joy along the way.

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Amputation and wound care behavior in C. floridanus (A) Illustration of a worker providing wound care on a femur-injured individual. (B) A worker amputating (biting) the injured leg at the trochanter. (C) A worker providing wound care on the newly created trochanter wound after amputation. (D) Percentage of amputations performed on ants with an infected or sterile femur (red) or tibia (blue) injury after 24 h. Numbers above the bars represent the sample size for each treatment. (E) Percentage of time the injured ant received wound care behavior over 3 h, binned in 10 min intervals, with a local polynomial regression (loess) showing a 95% confidence interval for the first 3 h after the experimental femur injury (femur, red: n = 8) and the first 3 h after amputation on the trochanter wound (trochanter, brown: n = 7).

Surgery — Not Just For Humans Anymore

July 12, 2024 by 21 Comments

Sometimes, a limb is damaged so badly that the only way to save the patient is to amputate it. Researchers have now found that humans aren’t the only species to perform life-saving amputations. [via Live Science]

While some ants have a gland that secretes antimicrobial chemicals to treat wounds in their comrades, Florida carpenter ants have lost this ability over the course of evolution. Lacking this chemical means to treat wounds, these ants have developed the first observed surgery in an animal other than humans.

When an ant has a wounded leg, its fellow ants analyze the damage. If the femur is the site of the wound, the other ants removed the damaged limb in 76% of cases by biting it off, while tibial wounds were treated in other ways. Experimental amputations of the tibia by researchers showed no difference in survivability compared to leaving the limb intact unless the amputation was performed immediately, so it seems the ants know what they’re doing.

Maybe these ants could be helpful surgical aids with some cyborg additions since they’ve already got experience? Ants can help you with programming too if that’s more your speed.

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Tiny Transceiver Gets It Done With One Transistor

July 12, 2024 by 23 Comments

When we first spotted the article about a one-transistor amateur radio transceiver, we were sure it was a misprint. We’ve seen a lot of simple low-power receivers using a single transistor, and a fair number of one-transistor transmitters. But both in one package with only a single active component? Curiosity piqued.

It turns out that [Ciprian Popica (YO6DXE)]’s design is exactly what it says on the label, and it’s pretty cool to boot. The design is an improvement on a one-transistor transceiver called “El Pititico” and is very petite indeed. The BOM has only about fifteen parts including a 2N2222 used as a crystal-controlled oscillator for both the transmitter and the direct-conversion receiver, along with a handful of passives and a coupe of hand-wound toroidal inductors. There’s no on-board audio section, so you’ll have to provide an external amplifier to hear the signals; some might say this is cheating a bit from the “one transistor” thing, but we’ll allow it. Oh, and there’s a catch — you have to learn Morse code, since this is a CW-only transmitter.

As for construction, [Ciprian] provides a nice PCB  layout, but the video below seems to show a more traditional “ugly style” build, which we always appreciate. The board lives in a wooden box small enough to get lost in a pocket. The transceiver draws about 1.5 mA while receiving and puts out a fairly powerful 500 mW signal, which is fairly high in the QRP world. [Ciprian] reports having milked a full watt out of it with some modifications, but that kind of pushes the transistor into Magic Smoke territory. The signal is a bit chirpy, too, but not too bad.

We love minimalist builds like these; they always have us sizing up our junk bin and wishing we were better stocked on crystals and toroids. It might be good to actually buckle down and learn Morse too.

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