Busted: Toilet Paper As Solder Wick

June 14, 2024 by 29 Comments

It didn’t take long for us to get an answer to the question nobody was asking: Can you use toilet paper as solder wick? And unsurprisingly, the answer is a resounding “No.”

Confused? If so, you probably missed our article a few days ago describing the repair of corroded card edge connectors with a bit of homebrew HASL. Granted, the process wasn’t exactly hot air solder leveling, at least not the way PCB fabs do it to protect exposed copper traces. It was more of an en masse tinning process, for which [Adrian] used a fair amount of desoldering wick to pull excess solder off the pins.

During that restoration, [Adrian] mentioned hearing that common toilet paper could be used as a cheap substitute for desoldering wick. We were skeptical but passed along the tip hoping someone would comment on it. Enter [KDawg], who took up the challenge and gave it a whirl. The video below shows attempts to tin a few pins on a similar card-edge connector and remove the excess with toilet paper. The tests are done using 63:37 lead-tin solder, plus and minus flux, and using Great Value TP in more or less the same manner you’d use desoldering braid. The results are pretty much what you’d expect, with charred toilet paper and no appreciable solder removal. The closest it comes to working is when the TP sucks up the melted flux. Stay tuned for the bonus positive control footage at the end, though; watching that legit Chemtronics braid do its thing is oddly satisfying.

So, unless there’s some trick to it, [KDawg] seems to have busted this myth. If anyone else wants to give it a try, we’ll be happy to cover it.

Continue reading “Busted: Toilet Paper As Solder Wick” →

2024 Business Card Challenge: BAUDI/O For The Audio Hacker

June 14, 2024 by 6 Comments

[Simon B] enters our 2024 Business Card Challenge with BAUDI/O, a genuinely useful audio output device. The device is based around the PCM2706 DAC, which handles all the USB interfacing and audio stack for you, needing only a reference crystal and the usual sprinkling of passives. This isn’t just a DAC board, though; it’s more of an audio experimentation tool with two microcontrollers to play with.

The first ATTiny AT1614 is hooked up to a simple LED vu-meter, and the second is connected to the onboard AD5252 digipot, which together allows one to custom program the response to the digital inputs to suit the user. The power supply is taken from the USB connection. A pair of ganged LM2663 charge-pump inverters allow inversion of the 5V rail to provide the necessary -5 V for the output amplifiers.  This is then fed to the LM4562-based CMoy-type headphone amplifier.  This design has a few extra stages, so with a bit of soldering, you can adjust the output filtering to suit. An LM1117 derives 3.3 V from the USB input to provide another power rail,  mostly for the DAC.

There’s not much more to say other than this is a nice, clean audio design, with everything broken out so you can tinker with it and get exactly the audio experience you want.

2024 Business Card Challenge

RIP Lynn Conway, Whose Work Gave Us VLSI And Much More

June 14, 2024 by 47 Comments

Lynn Conway, American engineer and computer scientist, passed away at the age of 86 from a heart condition on June 9th, at her Michigan home. Her work in the 1970s led to the integrated circuit design and manufacturing methodology known as Very Large Scale Integration, or VLSI, something which touches almost all facets of the world we live in here in 2024.

It was her work at the legendary Xerox PARC that resulted in VLSI, and its subsequent publication had the effect through the 1980s of creating a revolution in the semiconductor industry. By rendering an IC into a library of modular units that could be positioned algorithmically, VLSI enabled much more efficient use of space on the die, and changed the design process from one of layout into one of design. In simple terms, by laying out pre-defined assemblies with a computer rather than individual components by hand, a far greater density of components could be achieved, and more powerful circuits could be produced.

You may have also heard of Lynne Conway, not because of her VLSI work, but because as a transgender woman she found herself pursuing a parallel career as an activist in her later decades. As an MIT student in the 1950s she had tried to transition but been beaten back by the attitudes of the time, before dropping out and only returning to Columbia University to finish her degree a few years later in the early 1960s. A job at IBM followed, but when she announced her intent to transition she was fired from IBM and lost access to her family. Continue reading “RIP Lynn Conway, Whose Work Gave Us VLSI And Much More” →

Hackaday Podcast Episode 275: Mud Pulse Telemetry, 3D Printed Gears In Detail, And Display Hacking In Our Future

June 14, 2024 by No comments

Join Hackaday Editors Elliot Williams and Tom Nardi for a review of the best stories to grace the front page of Hackaday this week. Things kick off with the news about Raspberry Pi going public, and what that might mean for everyone’s favorite single-board computer. From there they’ll cover the technology behind communicating through mud, DIY pressure vessels, pushing the 1983 TRS-80 Model 100 to its limits, and the reality of 3D printing how that the hype has subsided. You’ll also hear about modifying Nissan’s electric vehicles, bringing new life to one of the GameCube’s oddest peripherals, and an unusually intelligent kayak.

The episode wraps up with some interesting (or depressing) numbers that put into perspective just how much copper is hiding in our increasingly unused telephone network, and a look at how hardware hackers can bend the display technology that’s used in almost all modern consumer electronics to our advantage.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Grab the Collector’s Edition MP3 of this week’s episode right here. Certificate of authenticity not included.

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How Good (Or Bad) Are Fake Power Semiconductors?

June 14, 2024 by 12 Comments

We all know that there’s a significant risk of receiving fake hardware when buying parts from less reputable sources. These counterfeit parts are usually a much cheaper component relabeled as a more expensive one, with a consequent reduction in performance. It goes without saying that the fake is lower quality then, but by just how much? [Denki Otaku] has a video comparing two power FETs, a real and a fake one, and it makes for an interesting watch.

For once the fact that a video is sponsored is a positive, for instead of a spiel about a dodgy VPN or a game involving tanks, he takes us into Keysight’s own lab to work with some high-end component characterization instruments we wouldn’t normally see. A curve tracer produces the equivalents of all those graphs from the data sheet, while a double pulse tester puts the two transistors through a punishing high-power dynamic characteristic examination. Then back in his own lab we see the devices compared in a typical circuit, a high-power buck converter. The most obvious differences between the two parts reveal something about their physical difference, as a lower parasitic capacitance and turn-on time with a higher on resistance for the fake is a pointer to it being a smaller part. Decapping the two side by side backs this up.

So it should be no surprise that a fake part has a much lower performance than the real one. In this case it’s a fully working transistor, but one that works very inefficiently at the higher currents which the real one is designed for. We can all be caught by fakes, even Hackaday scribes.

Continue reading “How Good (Or Bad) Are Fake Power Semiconductors?” →

This Week In Security: Unicode Strikes Again, Trust No One (Redditor), And More

June 14, 2024 by 7 Comments

There’s a popular Sysadmin meme that system problems are “always DNS”. In the realm of security, it seems like “it’s always Unicode“. And it’s not hard to see why. Unicode is the attempt to represent all of Earth’s languages with a single character set, and that means there’s a lot of very similar characters. The two broad issues are that human users can’t always see the difference between similar characters, and that libraries and applications sometimes automatically convert exotic Unicode characters into more traditional text.

This week we see the resurrection of an ancient vulnerability in PHP-CGI, that allows injecting command line switches when a web server launches an instance of PHP-CGI. The solution was to block some characters in specific places in query strings, like a query string starting with a dash.

The bypass is due to a Windows feature, “Best-Fit”, an automatic down-convert from certain Unicode characters. This feature works on a per-locale basis, which means that not every system language behaves the same. The exact bypass that has been found is the conversion of a soft hyphen, which doesn’t get blocked by PHP, into a regular hyphen, which can trigger the command injection. This quirk only happens when the Windows locale is set to Chinese or Japanese. Combined with the relative rarity of running PHP-CGI, and PHP on Windows, this is a pretty narrow problem. The XAMPP install does use this arrangement, so those installs are vulnerable, again if the locale is set to one of these specific languages. The other thing to keep in mind is that the Unicode character set is huge, and it’s very likely that there are other special characters in other locales that behave similarly.

Downloader Beware

The ComfyUI project is a flowchart interface for doing AI image generation workflows. It’s an easy way to build complicated generation pipelines, and the community has stepped up to build custom plugins and nodes for generation. The thing is, it’s not always the best idea to download and run code from strangers on the Internet, as a group of ComfyUI users found out the hard way this week. The ComfyUI_LLMVISION node from u/AppleBotzz was malicious.

The node references a malicious Python package that grabs browser data and sends it all to a Discord or Pastebin. It appears that some additional malware gets installed, for continuing access to infected systems. It’s a rough way to learn. Continue reading “This Week In Security: Unicode Strikes Again, Trust No One (Redditor), And More” →

A Super-Simple Standalone WSPR Beacon

June 14, 2024 by 26 Comments

We’ve said it before and we’ll say it again: being able to build your own radios is the best thing about being an amateur radio operator. Especially low-power transmitters; there’s just something about having the know-how to put something on the air that’ll reach across the planet on a power budget measured in milliwatts.

This standalone WSPR beacon is a perfect example. If you haven’t been following along, WSPR stands for “weak-signal propagation reporter,” and it’s a digital mode geared for exploring propagation that uses special DSP algorithms to decode signals that are far, far down into the weeds; signal-to-noise ratios of -28 dBm are possible with WSPR.

Because of the digital nature of WSPR encoding and the low-power nature of the mode, [IgrikXD] chose to build a standalone WSPR beacon around an ATMega328. The indispensable Si5351 programmable clock generator forms the RF oscillator, the output of which is amplified by a single JFET transistor. Because timing is everything in the WSPR protocol, the beacon also sports a GPS receiver, ensuring that signals are sent only and exactly on the even-numbered minutes. This is a nice touch and one that our similar but simpler WSPR beacon lacked.

This beacon had us beat on performance, too. [IgrikXD] managed to hit Texas and Colorado from the edge of the North Sea on several bands, which isn’t too shabby at all with a fraction of a watt.

Thanks to [STR-Alorman] for the tip.

[via r/amateurradio]