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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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Undo Arduino Encryption With An Oscilloscope

July 14, 2024 by 16 Comments

Cryptography ain’t easy. Seemingly small details like how many times a computationally intensive loop runs can give the game away. [Lord Feistel] gives us a demo of how this could work with nothing more than poorly designed code, a resistor, and an oscilloscope.

The hardware side is, as mentioned, really simple. Put a resistor inline with the Arduino and monitor the voltage drop across the resistor with the scope. When the chip is working hard, it consumes more current, and code sections that take longer will show up as longer dips.

On the software end, it’s only a little more complicated.  The RSA encryption scheme involves a lot of exponentiation and modulo-taking. Here, [Lord Feistel] is targeting a naive way of computing the exponents quickly, and demonstrates how you can read the exponent straight out the chip’s power demand.

Implementing this attack against a real-world RSA algorithm, in the context of the Arduino doing other stuff, will be harder. And we don’t know if the algorithm implemented in “standard” Arduino libraries is smarter than this one. (If you know, let us know in the comments.) But still, this is a cool example of just how simple and straightforward it can be to eavesdrop on bad code.

If you only need to bypass encryption instead of breaking it, check out [Lord Feistel]’s other tutorial on power glitching that we featured previously. If you haven’t played around with the hardware side of security, it gets deep pretty quickly, but you can at least dip your toes in the shallow end with what you’ve got in your closet.

Wrap Your Keyboard With A Vacuum Former

July 14, 2024 by 4 Comments

Coloured keycaps are a common customisation when it comes to making your input device special. If you are working with modern tech it’s easy, there are plenty of vendors who can sell you keycaps for any purpose. With retro tech it’s never so simple, if a keycap hasn’t been made for decades you’re out of luck. This doesn’t faze [Drygol] though, who has solved the coloured retro keycap in a unique and non-destructive way. Wrap them in vinyl film using a vacuum former.

Vacuum formers are an often-underrated tool in the hardware arsenal, but as this project shows, they can produce startlingly good results. Original keycaps are placed on a 3D-printed scaffold before the vinyl is formed over them, then they are carefully cut out and a triangular edge on both sides is folded underneath, The result is an Amiga with a striking orange keyboard, and for us the best bit is that the original key is safely preserved under the vinyl.

[Drygol]’s exceptional work in the retrocomputing sphere has delighted us many times on these pages. There are too many examples to link here, but one we particularly liked was this nearly-all-new Amiga 2000.

Ask Hackaday: Has Firefox Finally Gone Too Far?

July 14, 2024 by 119 Comments

In a world where so much of our lives depend on the use of online services, the web browser used to access those services becomes of crucial importance. It becomes a question of whether we trust the huge corporate interests which control this software with such access to our daily lives, and it is vital that the browser world remains a playing field with many players in the game.

The mantle has traditionally fallen upon Mozilla’s Firefox browser to represent freedom from corporate ownership, but over the last couple of years even they have edged away from their open source ethos and morphed into an advertising company that happens to have a browser. We’re asking you: can we still trust Mozilla’s Firefox, when the latest version turns on ad measurement by default?

Such has been the dominance of Google’s Chromium in the browser world, that it becomes difficult to find alternatives which aren’t based on it. We can see the attraction for developers, instead of pursuing the extremely hard task of developing a new browser engine, just use one off-the-shelf upon which someone else has already done the work. As a result, once you have discounted browsers such as the venerable Netsurf or Dillo which are cool as heck but relatively useless for modern websites, the choices quickly descend into the esoteric. There are Ladybird and Servo which are both promising but still too rough around the edges for everyday use, so what’s left? Probably LibreWolf represents the best option, a version of Firefox with a focus on privacy and security.

We’re interested in your views on this topic, because we know you’ll have a lot to say about it. Meanwhile if you’re a Firefox user who’s upgraded to version 128 and you’re not sure what to do, don’t panic. Find the settings page, go to “Privacy and Security”, and un-check the “Website Advertising Preferences” checkbox.

The Mysterious Roman Dodecahedron Was Possibly Just For Knitting

July 14, 2024 by 39 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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