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3 Articles

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.

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Hackaday Links: August 13, 2023

August 13, 2023 by 14 Comments

Remember that time when the entire physics community dropped what it was doing to replicate the extraordinary claim that a room-temperature semiconductor had been discovered? We sure do, and if it seems like it was just yesterday, it’s probably because it pretty much was. The news of LK-99, a copper-modified lead apatite compound, hit at the end of July; now, barely three weeks later, comes news that not only is LK-99 not a superconductor, but that its resistivity at room temperature is about a billion times higher than copper. For anyone who rode the “cold fusion” hype train back in the late 1980s, LK-99 had a bit of code smell on it from the start. We figured we’d sit back and let science do what science does, and sure enough, the extraordinary claim seems not to be able to muster the kind of extraordinary evidence it needs to support it — with the significant caveat that a lot of the debunking papers –and indeed the original paper on LK-99 — seem still to be just preprints, and have not been peer-reviewed yet.

So what does all this mean? Sadly, probably not much. Despite the overwrought popular media coverage, a true room-temperature and pressure superconductor was probably not going to save the world, at least not right away. The indispensable Asianometry channel on YouTube did a great video on this. As always, his focus is on the semiconductor industry, so his analysis has to be viewed through that lens. He argues that room-temperature superconductors wouldn’t make much difference in semiconductors because the place where they’d most likely be employed, the interconnects on chips, will still have inductance and capacitance even if their resistance is zero. That doesn’t mean room-temperature superconductors wouldn’t be a great thing to have, of course; seems like they’d be revolutionary for power transmission if nothing else. But not so much for semiconductors, and certainly not today.

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Flipper Zero “Smoking” A Smart Meter Is A Bad Look For Hardware Hackers

June 14, 2023 by 126 Comments

Alright, we’re calling it — we need a pejorative equivalent to “script kiddie” to describe someone using a Flipper Zero for annoyingly malign purposes. If you need an example, check out the apparent smart meter snuff video below.

The video was posted by [Peter Fairlie], who we assume is the operator of the Flipper Zero pictured. The hapless target smart meter is repeatedly switched on and off with the Flipper — some smart meters have contactors built in so that service can be disconnected remotely for non-payment or in emergencies — which rapidly starts and stops a nearby AC compressor. Eventually, the meter releases a puff of Magic Smoke, filling its transparent enclosure and obscuring the display. The Flipper’s operator mutters a few expletives at the results, but continues turning the meter on and off even more rapidly before eventually running away from the scene of the crime.

We qualify this as “apparent” because the minute we saw this over on RTL-SDR.com, we reached out to reverse engineer par excellence and smart meter aficionado [Hash] for an opinion. Spoiler alert: [Hash] thinks it’s an elaborate hoax; the debunking starts at the 4:32 mark in the second video below. The most damning evidence is that the model of smart meter shown in the video doesn’t even have a disconnect, so whatever [Peter] is controlling with the Flipper, it ain’t the meter. Also, [Hash] figured out where [Peter] lives — he doxxed himself in a previous video — and not only does the meter shown in the video not belong to the Canadian power company serving the house, StreetView shows that there’s a second meter, suggesting that this meter may have been set up specifically for the lulz.

It should go without saying that Hackaday is about as supportive of hardware experimentation as an organization can be. But there have to be some boundaries, and even if this particular video turns out to be a hoax, it clearly steps over the line. Stuff like this paints a poor picture of what hardware hacking is all about, and leads to unintended consequences that make it harder for all of us to get the tools we need.

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