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Hackaday Links: October 18, 2020

Remember subliminal advertising? The idea was that a movie theater operator would splice a single frame showing a bucket of hot buttered popcorn into a movie, which moviegoers would see and process on a subconcious level and rush to the concession stand to buy the tub o’ petrochemical-glazed starch they suddenly craved. It may or may not work on humans, but it appears to work on cars with advanced driver assistance, which can be spoofed by “phantom street signs” flashed on electronic billboards. Security researchers at Ben Gurion University stuck an image of a stop sign into a McDonald’s ad displayed on a large LCD screen by the side of the road. That was enough to convince a Tesla Model X to put on the brakes as it passed by the sign. The phantom images were on the screen anywhere from an eighth of a second to a quarter second, so these aren’t exactly subliminal messages, but it’s still an interesting attack that bears looking into. And while we’re skeptical about the whole subliminal advertising thing in the first place, for some reason we really want a bacon cheeseburger right now.

Score one for the good guys in the battle against patent trolls. Mycroft AI, makers of open-source voice assistants, proudly announced their latest victory against what they claim are patent trolls. This appears to be one of those deals where a bunch of investors get together and buy random patents, and then claim that a company that actually built something infringes on their intellectual property. Mycroft got a letter from one such entity and decided to fight it; they’ve won two battles so far against the alleged trolls and it looks pretty good going forward. They’re not pulling their punches, either, since Mycroft is planning to go after the other parties for legal expenses and punitive damages under the State of Missouri’s patent troll legislation. Here’s hoping this sends a message to IP squatters that it may not be worth the effort and that their time and money are better spent actually creating useful things.

Good news from Mars — The Mole is finally completely buried! We’ve been following the saga of the HP³, or “Heat Flow and Physical Properties Package” aboard NASA’s Mars InSight lander for quite a while. The self-drilling “Mole”, which is essentially the guts of an impact screwdriver inside a streamlined case, has been having trouble dealing with the Martian regolith, which is simultaneously too soft to offer the friction needed to keep the penetrator in its hole, but also too hard to pierce in places where there is a “duricrust” of chemically amalgamated material below the surface. It took a lot of delicate maneuvers with the lander’s robotic arm to get the Mole back on track, and it’s clearly not out of the woods yet — it needs to get down to three meters depth or so to do the full program of science it was designed for.

If watching Martian soil experiments proceed doesn’t scratch your itch for space science, why not try running your own radio astronomy experiments? Sure, you could build your own radio telescope to do that, but you don’t even have to go that far — just log into PICTOR, the free-to-use radio telescope. It’s a 3.2-m parabolic dish antenna located near Athens, Greece that’s geared toward hydrogen line measurements of the galaxy. You can set up an observation run and have the results mailed back to you for later analysis.

Here’s a fun, quick hack for anyone who hates the constant drone of white noise coming from fans. Build Comics apparently numbers themselves among that crowd, and decided to rig up a switch to turn on their fume extractor only when the soldering iron is removed from its holder. This hack was executed on a classic old Weller soldering station, but could easily be adapted to Hakko or other irons

And finally, if you’ve never listened to a Nobel laureate give a lecture, here’s your chance. Andrea Ghez, co-winner of the 2020 Nobel Prize in physics for her work on supermassive black holes, will be giving the annual Maria Goeppert Mayer lecture at the University of Chicago. She’ll be talking about exactly what she won the Nobel for: “The Monster at the Heart of Our Galaxy”, the supermassive black hole Sagittarius A*. We suspect the talk was booked before the Nobel announcement, so in normal times the room would likely be packed. But one advantage to the age of social distancing is that everything is online, so you can tune into a livestream of the lecture on October 22.

Hackaday Podcast 089: 770 Potato Battery, Printing Resin Resist, And No-Internet Video Chat

Hackaday editors Mike Szczys and Elliot Williams weigh the hacking gold found across the internet this week. We can’t get over the epic adventure that went into making a battery from 100 pounds of potatoes. It turns out you don’t need Internet for video conferencing as long as you’re within a coupe of kilometers of everyone else. And move over toner transfer method, resin printers want a shot at at-home PCB etching. We’ll take a look at what the Tesla selfie cam is doing under the hood, and lose our marbles over a ball-bearing segment clock that’s defying gravity.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (60 MB or so.)

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This Week In Security: BleedingTooth, Bad Neighbors, And Unpickable Locks

This week, the first details of BleedingTooth leaked onto Twitter, setting off a bit of a frenzy. The full details have yet to be released, but what we know is concerning enough. First off, BleedingTooth isn’t a single vulnerability, but is a set of at least 3 different CVEs (Shouldn’t that make it BleedingTeeth?). The worst vulnerability so far is CVE-2020-12351, which appears to be shown off in the video embedded after the break.

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Axe Hacks: Spinning Knobs And Flipping Switches

From a guitar hacking point of view, the two major parts that are interesting to us are the pickups and the volume/tone control circuit that lets you adjust the sound while playing. Today, I’ll get into the latter part and take a close look at the components involved — potentiometers, switches, and a few other passive components — and show how they function, what alternative options we have, and how we can re-purpose them altogether.

In that sense, it’s time to heat up the soldering iron, get out the screwdriver, and take off that pick guard / open up that back cover and continue our quest for new electric guitar sounds. And if the thought of that sounds uncomfortable, skip the soldering iron and grab some alligator clips and a breadboard. It may not be the ideal environment, but it’ll work.

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Linux Fu: Global Search And Replace With Ripgrep

If you are even a casual Linux user, you probably know how to use grep. Even if you aren’t a regular expression guru, it is easy to use grep to search for lines in a file that match anything from simple strings to complex patterns. Of course, grep is fine for looking, but what if you want to find things and change them. Maybe you want to change each instance of “HackADay” to “Hackaday,” for example. You might use sed, but it is somewhat hard to use. You could use awk, but as a general-purpose language, it seems a bit of overkill for such a simple and common task. That’s the idea behind ripgrep which actually has the command name rg. Using rg, you can do things that grep can do using more modern regular expressions and also do replacements.

A Note on Installing Ripgrep

Your best bet is to get ripgrep from your repositories. When I tried running KDE Neon, it helpfully told me that I could install a version using apt or take a Snap version that was newer. I usually hate installing a snap, but I did anyway. It informed me that I had to add –classic to the install line because ripgrep could affect files outside the Snap sandbox. Since the whole purpose of the program is to change files, I didn’t think that was too surprising, so I did the install.

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Quality Control, Done Anywhere

Modern society has brought us all kinds of wonders, including rapid intercontinental travel, easy information access, and decreased costs for most consumer goods thanks to numerous supply chains. When those supply chains break down as a result of a natural disaster or other emergency, however, the disaster’s effects can be compounded without access to necessary supplies. That’s the focus of Field Ready, a nonprofit that sets up small-scale manufacturing in places without access to supply chains, or whose access has been recently disrupted.

As part of this year’s Hackaday Prize, a each of our four nonprofit partners outline specific needs that became the targets of a design and build challenge. Field Ready was one of those nonprofits, and for the challenge they focused on quality control for their distributed manufacturing system. We took a look at Field Ready back in June to explore some of the unique challenges associated with their work, which included customers potentially not knowing that a product they procured came from Field Ready in the first place, leading to very little feedback on the performance of the products and nowhere to turn when replacements are needed.

The challenge was met by a dream team whose members each received a $6,000 microgrant to work full time on the project. The’ve just made their report on an easier way of tracking all of the products produced, and identifying them even for those not in the organization. As a result, Field Ready has a much improved manufacturing and supply process which allows them to gather more data and get better feedback from users of their equipment. Join us after the break for a closer look at the system and to watch the team’s presentation video.

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Fail Of The Week: Putting Guitar Strings On A Piano

The piano is a bit of an oddball within the string instrument family. Apart from rarely seeing people carry one around on the bus or use its case to discretely conceal a Tommy Gun, the way the strings are engaged in the first place — by having little hammers attached to each key knock the sound of of them — is rather unique compared to the usual finger or bow movement. Still, it is a string instrument, so it’s only natural to wonder what a piano would sound like if it was equipped with guitar strings instead of piano wire. Well, [Mattias Krantz] went on to actually find out the hard way, and shows the results in this video.

After a brief encounter with a bolt cutter, the point of no return was reached soon on. Now, the average piano has 88 keys, and depending on the note, a single key might have up to three strings involved at once. In case of [Mattias]’ piano — which, in his defense, has certainly seen better days — a total of 210 strings had to be replaced for the experiment. Guitars on the other hand have only six, so not only did he need 35 packs of guitar strings, the gauge and length variety is quite limited on top. What may sound like a futile endeavor from the beginning didn’t get much better over time, and at some point, the strings weren’t long enough anymore and he had to tie them together. Along with some inevitable breakage, he unfortunately ran out of strings and couldn’t finish the entire piano, though it seems he still managed to roughly cover a guitar’s frequency range, so that’s an appropriate result.

We’re not sure if [Mattias] ever expected this to actually work, but it kinda does — there is at least some real sound. Are the results more than questionable though? Oh absolutely, but we have to admire the audacity and perseverance he showed to actually pull through with this. It took him 28 hours just to get the guitar strings on, and another good amount of time to actually get them all in tune. Did it pay off? Well, that depends how you look at it. It definitely satisfied his and other’s curiosity, and the piano produces some really unique and interesting sounds now — but check for yourself in the video after the break. But that might not be for everyone, so luckily there are less final ways to change a piano’s sound. And worst case, you can always just turn it into a workbench.

(Thanks for the tip, [Keith])

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