Hackaday Links: May 30, 2021

That collective “Phew!” you heard this week was probably everyone on the Mars Ingenuity helicopter team letting out a sigh of relief while watching telemetry from the sixth and somewhat shaky flight of the UAV above Jezero crater. With Ingenuity now in an “operations demonstration” phase, the sixth flight was to stretch the limits of what the craft can do and learn how it can be used to scout out potential sites to explore for its robot buddy on the surface, Perseverance.

While the aircraft was performing its 150 m move to the southwest, the stream from the downward-looking navigation camera dropped a single frame. By itself, that wouldn’t have been so bad, but the glitch caused subsequent frames to come in with the wrong timestamps. This apparently confused the hell out of the flight controller, which commanded some pretty dramatic moves in the roll and pitch axes — up to 20° off normal. Thankfully, the flight controller was designed to handle just such an anomaly, and the aircraft was able to land safely within five meters of its planned touchdown. As pilots say, any landing you can walk away from is a good landing, so we’ll chalk this one up as a win for the Ingenuity team, who we’re sure are busily writing code to prevent this from happening again.

If wobbling UAVs on another planet aren’t enough cringe for you, how about a blind mechanical demi-ostrich drunk-walking up and down a flight of stairs? The work comes from the Oregon State University and Agility Robotics, and the robot in question is called Cassie, an autonomous bipedal bot with a curious, bird-like gait. Without cameras or lidar for this test, the robot relied on proprioception, which detects the angle of joints and the feedback from motors when the robot touches a solid surface. And for ten tries up and down the stairs, Cassie did pretty well — she only failed twice, with only one counting as a face-plant, if indeed she had a face. We noticed that the robot often did that little move where you misjudge the step and land with the instep of your foot hanging over the tread; that one always has us grabbing for the handrail, but Cassie was able to power through it every time. The paper describing how Cassie was trained is pretty interesting — too bad ED-209’s designers couldn’t have read it.

So this is what it has come to: NVIDIA is now purposely crippling its flagship GPU cards to make them less attractive to cryptocurrency miners. The LHR, or “Lite Hash Rate” cards include new-manufactured GeForce RTX 3080, 3070, and 3060 Ti cards, which will now have reduced Ethereum hash rates baked into the chip from the factory. When we first heard about this a few months ago, we puzzled a bit — why would a GPU card manufacturer care how its cards are used, especially if they’re selling a ton of them. But it makes sense that NVIDIA would like to protect their brand with their core demographic — gamers — and having miners snarf up all the cards and leaving none for gamers is probably a bad practice. So while it makes sense, we’ll have to wait and see how the semi-lobotomized cards are received by the market, and how the changes impact other non-standard uses for them, like weather modeling and genetic analysis.

Speaking of crypto, we found it interesting that police in the UK accidentally found a Bitcoin mine this week while searching for an illegal cannabis growing operation. It turns out that something that uses a lot of electricity, gives off a lot of heat, and has people going in and out of a small storage unit at all hours of the day and night usually is a cannabis farm, but in this case it turned out to be about 100 Antminer S9s set up on janky looking shelves. The whole rig was confiscated and hauled away; while Bitcoin mining is not illegal in the UK, stealing the electricity to run the mine is, which the miners allegedly did.

And finally, we have no idea what useful purpose this information serves, but we do know that it’s vitally important to relate to our dear readers that yellow LEDs change color when immersed in liquid nitrogen. There’s obviously some deep principle of quantum mechanics at play here, and we’re sure someone will adequately explain it in the comments. But for now, it’s just a super interesting phenomenon that has us keen to buy some liquid nitrogen to try out. Or maybe dry ice — that’s a lot easier to source.

Oil Wells Done Rube-Goldberg Style: Flatrods And Jerk Lines

The news is full of the record low oil price due to the COVID-19-related drop in demand. The benchmark Brent crude dipped below $20 a barrel, while West Texas intermediate entered negative pricing. We’ve all become oil market watchers overnight, and for some of us that’s led down a rabbit hole of browsing to learn a bit about how oil is extracted.

Many of us will have seen offshore oil platforms or nodding pumpjacks, but how many of us outside the industry have much more than a very superficial knowledge of it? Of all the various technologies to provide enlightenment of the curious technologist there’s one curious survivor from the earliest days of the industry that is definitely worth investigation, the jerk line oil well pump. This is a means of powering a reciprocating pump in an oil well not through an individual engine or motor as in the pump jacks, but in a system of rods transmitting power over long distances from a central location by means of reciprocating motion. It’s gloriously simple, which has probably contributed to its survival in a few small-scale oil fields over a century and a half after its invention.

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How Can Heavy Metal Fly?

Scientists found a surprising amount of lead in a glacier. They were studying atmospheric pollution by sampling ice cores taken from Alpine glaciers. The surprising part is that they found more lead in strata from the late 13th century than they had in those deposited at the height of the Industrial Revolution. Surely mediaeval times were supposed to be more about knights in shining armour than dark satanic mills, what on earth was going on? Why was the lead industry in overdrive in an age when a wooden water wheel represented high technology?

The answer lies in the lead smelting methods used a thousand miles away from that glacier, and in the martyrdom of a mediaeval saint.

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Get Compressed Air From Falling Water With The Trompe

If you’re like us, understanding the processes and methods of the early Industrial Revolution involved some hand waving. Take the blast furnace, which relies on a steady supply of compressed air to stoke the fire and supply the oxygen needed to smelt iron from ore. How exactly was air compressed before electricity? We assumed it would have been from a set of bellows powered by a water wheel, and of course that method was used, but it turns out there’s another way to get compressed air from water: the trompe.

As [Grady] from Practical Engineering explains in the short video below, the trompe was a clever device used to create a steady supply of high-pressure compressed air. To demonstrate the process, he breaks out his seemingly inexhaustible supply of clear acrylic piping to build a small trompe. The idea is to use water falling around a series of tubes to create a partial vacuum and entrain air bubbles. The bubbles are pulled down a vertical tube by the turbulence of the water, and then enter a horizontal section where the flow evens out. The bubbles rise to the top of the horizontal tube where they are tapped off by another vertical tube, as the degassed water continues into a second vertical section, the height of which determines the pressure of the stored air. It’s ingenious, requiring no power and no moving parts, and scales up well – [Grady] relates a story about one trompe that provided compressed air commercially for mines in Canada.

Need an electricity-free way to pump water instead of air? Check out this hydraulic ram pump that takes its power from the water it pumps.

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Radio Free Blockchain: Bitcoin From Space

Cryptocurrencies: love them, hate them, or be baffled by them, but don’t think you can escape them. That’s the way it seems these days at least, with news media filled with breathless stories about Bitcoin and the other cryptocurrencies, and everyone from Amazon to content creators on YouTube now accepting the digital currency for payments. And now, almost everyone on the planet is literally bathed in Bitcoin, or at least the distributed ledger that makes it work, thanks to a new network that streams the Bitcoin blockchain over a constellation of geosynchronous satellites.

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Hackaday Visits The Electric City

Much to the chagrin of local historians, the city of Scranton, Pennsylvania is today best known as the setting for the American version of The Office. But while the exploits of Dunder Mifflin’s best and brightest might make for a good Netflix binge, there’s a lot more to the historic city than the fictional paper company. From its beginnings as a major supplier of anthracite coal to the introduction of America’s first electrically operated trolley system on its streets, Scranton earned its nickname “The Electric City” by being a major technological hub from the Industrial Revolution through to the Second World War.

Today, the mines and furnaces of Scranton lie silent but not forgotten. In the 1980’s, the city started turning what remained of their industrial sites into historic landmarks and museums with the help of State and Federal grants. I recently got a chance to tour some of these locations, and came away very impressed. They’re an exceptional look into the early technology and processes which helped turn America into an industrial juggernaut.

While no substitute for visiting these museums and parks for yourself, hopefully the following images and descriptions will give you an idea of what kind of attractions await visitors to the modern day Electric City.

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The Science Of Landing On An Asteroid

Exploiting the resources of the rock-strewn expanse of space between Mars and the outer planets has been the stuff of science fiction for ages. There’s gold in them ‘thar space rocks, or diamonds, or platinum, or something that makes them attractive targets for capitalists and scientists alike. But before actually extracting the riches of the asteroid belt, stuck here as we are at the bottom of a very deep gravity well that’s very expensive to climb out of, we have to answer a few questions. Like, how does one rendezvous with an asteroid? What’s involved with maneuvering near a comparatively tiny celestial body? And most importantly, how exactly does one land on an asteroid and do any useful work?

Back in June, a spacecraft launched by the Japanese Aerospace Exploration Agency (JAXA) finally caught up to an asteroid named Ryugu after having chased it for the better part of four years. The Hayabusa2 was equipped to answer all those questions and more, and as it settled in close to the asteroid with a small fleet of robotic rovers on board, it was about to make history. Here’s how they managed to not only land on an asteroid, but how the rovers move around on the surface, and how they’ll return samples of the asteroid to Earth for study.

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