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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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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Getting Rid Of All The Space Junk In Earth’s Backyard

Space, as the name suggests, is mostly empty. However, since the first satellite launch in 1957, mankind began to populate the Earth orbit with all kinds of spacecraft. On the downside, space also became more and more cluttered with trash from defunct or broken up rocket stages and satellites. Moving at speeds of nearly 30,000 km/h, even the tiniest object can pierce a hole through your spacecraft. Therefore, space junk poses a real threat for both manned and unmanned spacecraft and that is why space agencies are increasing their efforts into tracking, avoiding, and getting rid of it.
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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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Lowering The Bar For Exam Software Security

Most standardized tests have a fee: the SAT costs $50, the GRE costs $200, and the NY Bar Exam costs $250. This year, the bar exam came at a much larger cost for recent law school graduates — their privacy.

Many in-person events have had to find ways to move to the internet this year, and exams are no exception. We’d like to think that online exams shouldn’t be a big deal. It’s 2020. We have a pretty good grasp on how security and privacy should work, and it shouldn’t be too hard to implement sensible anti-cheating features.

It shouldn’t be a big deal, but for one software firm, it really is.

The NY State Board of Law Examiners (NY BOLE), along with several other state exam boards, chose to administer this year’s bar exam via ExamSoft’s Examplify. If you’ve missed out on the Examplify Saga, following the Diploma Privilege for New York account on Twitter will get you caught up pretty quickly. Essentially, according to its users, Examplify is an unmitigated disaster. Let’s start with something that should have been settled twenty years ago.

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Andrea Ghez Gazes Into Our Galaxy’s Black Hole

Decades ago, Einstein predicted the existence of something he didn’t believe in — black holes. Ever since then, people have been trying to get a glimpse of these collapsed stars that represent the limits of our understanding of physics.

For the last 25 years, Andrea Ghez has had her sights set on the black hole at the center of our galaxy known as Sagittarius A*, trying to conclusively prove it exists. In the early days, her proposal was dismissed entirely. Then she started getting lauded for it. Andrea earned a MacArthur Fellowship in 2008. In 2012, she was the first woman to receive the Crafoord Prize from the Royal Swedish Academy of Sciences.

Image via SciTech Daily

Now Andrea has become the fourth woman ever to receive a Nobel Prize in Physics for her discovery. She shares the prize with Roger Penrose and Reinhard Genzel for discoveries relating to black holes. UCLA posted her gracious reaction to becoming a Nobel Laureate.

A Star is Born

Andrea Mia Ghez was born June 16th, 1965 in New York City, but grew up in the Hyde Park area of Chicago. Her love of astronomy was launched right along with Apollo program. Once she saw the moon landing, she told her parents that she wanted to be the first female astronaut. They bought her a telescope, and she’s had her eye on the stars ever since. Now Andrea visits the Keck telescopes — the world’s largest — six times a year.

Andrea was always interested in math and science growing up, and could usually be found asking big questions about the universe. She earned a BS from MIT in 1987 and a PhD from Caltech in 1992. While she was still in graduate school, she made a major discovery concerning star formation — that most stars are born with companion star. After graduating from Caltech, Andrea became a professor of physics and astronomy at UCLA so she could get access to the Keck telescope in Mauna Kea, Hawaii.

The Keck telescopes and the Milky Way. Image via Flickr

The Center of the Galaxy

Since 1995, Andrea has pointed the Keck telescopes toward the center of our galaxy, some 25,000 light years away. There’s a lot of gas and dust clouding the view, so she and her team had to get creative with something called adaptive optics. This method works by deforming the telescope’s mirror in real time in order to overcome fluctuations in the atmosphere.

Thanks to adaptive optics, Andrea and her team were able to capture images that were 10-30 times clearer than what was previously possible. By studying the orbits of stars that hang out near the center, she was able to determine that a supermassive black hole with four millions times the mass of the sun must lie there. Thanks to this telescope hack, Andrea and other scientists will be able to study the effects of black holes on gravity and galaxies right here at home. You can watch her explain her work briefly in the video after the break. Congratulations, Dr. Ghez, and here’s to another 25 years of fruitful research.

Firmware Hints That Tesla’s Driver Camera Is Watching

Currently, if you want to use the Autopilot or Self-Driving modes on a Tesla vehicle you need to keep your hands on the wheel at all times. That’s because, ultimately, the human driver is still the responsible party. Tesla is adamant about the fact that functions which allow the car to steer itself within a lane, avoid obstacles, and intelligently adjust its speed to match traffic all constitute a driver assistance system. If somebody figures out how to fool the wheel sensor and take a nap while their shiny new electric car is hurtling down the freeway, they want no part of it.

So it makes sense that the company’s official line regarding the driver-facing camera in the Model 3 and Model Y is that it’s there to record what the driver was doing in the seconds leading up to an impact. As explained in the release notes of the June 2020 firmware update, Tesla owners can opt-in to providing this data:

Help Tesla continue to develop safer vehicles by sharing camera data from your vehicle. This update will allow you to enable the built-in cabin camera above the rearview mirror. If enabled, Tesla will automatically capture images and a short video clip just prior to a collision or safety event to help engineers develop safety features and enhancements in the future.

But [green], who’s spent the last several years poking and prodding at the Tesla’s firmware and self-driving capabilities, recently found some compelling hints that there’s more to the story. As part of the vehicle’s image recognition system, which usually is tasked with picking up other vehicles or pedestrians, they found several interesting classes that don’t seem necessary given the official explanation of what the cabin camera is doing.

If all Tesla wanted was a few seconds of video uploaded to their offices each time one of their vehicles got into an accident, they wouldn’t need to be running image recognition configured to detect distracted drivers against it in real-time. While you could make the argument that this data would be useful to them, there would still be no reason to do it in the vehicle when it could be analyzed as part of the crash investigation. It seems far more likely that Tesla is laying the groundwork for a system that could give the vehicle another way of determining if the driver is paying attention.

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