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Hackaday Links: May 22, 2022

It looks like it’s soon to be lights out for the Mars InSight lander. In the two years that the lander has been studying the geophysics of Mars from its lonely post on Elysium Planitia, InSight’s twin solar arrays have been collecting dust, and now are so dirty that they’re only making about 500 watt-hours per sol, barely enough to run the science packages on the lander. And that’s likely to worsen as the Martian winter begins, which will put more dust in the sky and lower the angle of the Sun, reducing the sunlight that’s incident to the panels. Barring a “cleaning event” courtesy of a well-placed whirlwind, NASA plans to shut almost everything down on the lander other than the seismometer, which has already captured thousands of marsquakes, and the internal heaters needed to survive the cold Martian nights. They’re putting a brave face on it, emphasizing the continuing science and the mission’s accomplishments. But barely two years of science and a failed high-profile experiment aren’t quite what we’ve come to expect from NASA missions, especially one with an $800 million price tag.

Closer to home, it turns out there’s a reason sailing ships have always had human crews: to fix things that go wrong. That’s the lesson learned by the Mayflower Autonomous Ship as it attempted the Atlantic crossing from England to the States, when it had to divert for repairs recently. It’s not clear what the issue was, but it seems to have been a mechanical issue, as opposed to a problem with the AI piloting system. The project dashboard says that the issue has been repaired, and the AI vessel has shoved off from the Azores and is once more beating west. There’s a long stretch of ocean ahead of it now, and few options for putting in should something else go wrong. Still, it’s a cool project, and we wish them a fair journey.

Have you ever walked past a display of wall clocks at the store and wondered why someone went to the trouble of setting the time on all of them to 10:10? We’ve certainly noticed this, and always figured it had something to do with some obscure horological tradition, like using “IIII” to mark the four o’clock hour on clocks with Roman numerals rather than the more correct “IV”. But no, it turns out that 10:10 is more visually pleasing, and least on analog timepieces, because it evokes a smile on a human face. The study cited in the article had volunteers rate how pleasurable watches are when set to different times, and 10:10 won handily based on the perception that it was smiling at them. So it’s nice to know how easily manipulated we humans can be.

If there’s anything more pathetic than geriatric pop stars trying to relive their glory days to raise a little cash off a wave of nostalgia, we’re not sure what it could be. Still, plenty of acts try to do it, and many succeed, although seeing what time and the excesses of stardom have wrought can be a bit sobering. But Swedish megastars ABBA appear to have found a way to cash in on their fame gracefully, by sending digital avatars out to do their touring for them. The “ABBA-tars,” created by a 1,000-person team at Industrial Light and Magic, will appear alongside a live backing band for a residency at London’s Queen Elizabeth Olympic Park. The avatars represent Benny, Bjorn, Agnetha, and Anni-Frid as they appeared in the 1970s, and were animated thanks to motion capture suits donned while performing 40 songs. It remains to be seen how fans will buy into the concept, but we’ll say this — the Swedish septuagenarians look pretty darn good in skin-tight Spandex.

And finally, not that it has any hacking value at all, but there’s something shamefully hilarious about watching this poor little delivery bot getting absolutely wrecked by a train. It’s one of those food delivery bots that swarm over college campuses these days; how it wandered onto the railroad tracks is anyone’s guess. The bot bounced around a bit before slipping under the train’s wheels, with predictable results once the battery pack is smooshed.

Square Cuts On Aluminum Extrusion, No Mill Required

If you’re looking for the perfect excuse to buy that big, beautiful Bridgeport mill, we’ve got some bad news: it’s not going to be making perfectly square end cuts on aluminum extrusion. Sadly, it’s much more cost-effective to build this DIY squaring jig, and search for your tool justification elsewhere.

There’s no doubting the utility of aluminum extrusion in both prototyping and production builds, nor that the versatile structural members often add a bit of class to projects. But without square cuts, any frames built from them can be seriously out of whack, leading to misery and frustration down the road. [Midwest Cyberpunk]’s mill-less solution uses a cheap Harbor Freight router as a spindle for a carbide endmill, riding on a laser-cut acrylic baseplate fitted with wheels that ride in the V-groove of — you guessed it — aluminum extrusions. A fence and clamping system holds the extrusion firmly, and once trammed in, the jig quickly and easily squares extrusions that have been rough cut with a miter saw, angle grinder, or even a hacksaw. Check out the video below for a peek at the build details.

We love the simplicity and utility of this jig, but can see a couple of areas for improvement. Adding some quick-throw toggle clamps would be a nice touch, as would extending the MDF bed and fence a bit for longer cuts. But even as it is, this tool gets the job done, and doesn’t break the bank like a mill purchase might. Still, if your heart is set on a mill, who are we to stand in the way?

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Portable 3D Printer Gets Even Smaller, Faster, Better

How do you improve on a fast, capable 3D printer that sports an innovative design and is portable enough to fit in a printer spool box? Judging by what went into the Positron V3 portable printer, (video, embedded below) it takes a lot of hard work and an unwillingness to settle for compromise designs. Plus a few lucky breaks and some design wizardry.

When we first reported on [Kralyn]’s innovative “Positron” printer, its chief selling points were its portability and unique layout. With a fold-down Z-axis and a CoreXY-style drive in the base, plus an interesting 90° hot end and transparent heated build plate, the Positron managed to hit most of its design goals. But there’s always room for improvement, and Positron V3, shown in the video below, has made some pretty substantial leaps over that original concept.

The V3 design keeps the basic layout of the original, but greatly improves the usability and portability, while increasing performance and build volume. The heated borosilicate build plate is now held to the Z-axis drive with a much sturdier strut, and gets its juice through a high-temperature MagSafe connector. The X- and Y-axes are now driven by pancake steppers, which along with adding idler pulleys that are coaxial to the drive pulleys, make the CoreXY drive, and hence the printer’s base, much more compact. The printer is still much, much faster than most traditional gantry design, and print quality is on par with anything available commercially. And yes, it still fits into a standard 1-kg filament spool box when folded up.

We love this design, and the story of how the V3 came about and the intermediate V2 that didn’t make the cut is a fascinating case study in design. And as a bonus, [Kralyn] will open-source the V3 design, so you can build your own as soon as he releases the files.

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Falling Down The Labyrinth With Wooden Microphone Design

It used to be that when we featured one of [Frank Olson]’s DIY ribbon microphone builds, it was natural to focus on the fact that he was building them almost exclusively from wood. But despite how counterintuitive it may seem, and for as many comments as we get that his microphones shouldn’t work without metal in the ribbon motors, microphones like this wooden RCA Model 77 reproduction both look and sound great.

But ironically, this homage features a critical piece that’s actually not made of wood. The 77’s pickup pattern was cardioid, making for a directional mic that picked up sound best from the front, thanks to an acoustic labyrinth that increased the path length for incoming sound waves. [Frank]’s labyrinth was made from epoxy resin poured into a mold made from heavy paper, creating a cylinder with multiple parallel tunnels. The tops and bottoms of adjacent tunnels were connected together, creating an acoustic path over a meter long. The ribbon motor, as close to a duplicate of the original as possible using wood, sits atop the labyrinth block’s output underneath a wood veneer shell that does its best to imitate the classic pill-shaped windscreen of the original. The video below, which of course was narrated using the mic, shows its construction in detail.

If you want to check out [Frank]’s other wooden microphones, and you should, check out the beautiful Model 44 replica that looks ready for [Sinatra], or the Bk-5-like mics he whipped up for drum kit recording.

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Hackaday Links: May 15, 2022

It may be blurry and blotchy, but it’s ours. The first images of the supermassive black hole at the center of the Milky Way galaxy were revealed this week, and they caused quite a stir. You may recall the first images of the supermassive black hole at the center of the M87 galaxy from a couple of years ago: spectacular images that captured exactly what all the theories said a black hole should look like, or more precisely, what the accretion disk and event horizon should look like, since black holes themselves aren’t much to look at. That black hole, dubbed M87*, is over 55 million light-years away, but is so huge and so active that it was relatively easy to image. The black hole at the center of our own galaxy, Sagittarius A*, is comparatively tiny — its event horizon would fit inside the orbit of Mercury — a much closer at only 26,000 light-years or so. But, our black hole is much less active and obscured by dust, so imaging it was far more difficult. It’s a stunning technical achievement, and the images are certainly worth checking out.

Another one from the “Why didn’t I think of that?” files — contactless haptic feedback using the mouth is now a thing. This comes from the Future Interfaces Group at Carnegie-Mellon and is intended to provide an alternative to what ends up being about the only practical haptic device for VR and AR applications — vibrations from off-balance motors. Instead, this uses an array of ultrasonic transducers positioned on a VR visor and directed at the user’s mouth. By properly driving the array, pressure waves can be directed at the lips, teeth, and tongue of the wearer, providing feedback for in-world events. The mock game demonstrated in the video below is a little creepy — not sure how many people enjoyed the feeling of cobwebs brushing against the face or the splatter of spider guts in the mouth. Still, it’s a pretty cool idea, and we’d like to see how far it can go.

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Vicious Little Desktop Shredder Pulverizes Plastic Waste

We’ve all likely seen video of the enormous industrial shredders that eat engine blocks for lunch and spit out a stream of fine metal chips. The raw power of these metal-munching monsters is truly fearsome, and they appear to be the inspiration for SHREDII, the miniature plastic shredder for at-home recycling of plastic waste.

The fact that SHREDII isn’t all that large doesn’t make it any less dangerous, at least to things smaller and softer than engine blocks, like say fingers. The core of the shredder is a hexagonal axle carrying multiple laser-cut, sheet steel blades. The rotating blades are spaced out along the axle so they nest between a bed of stationary blades; rotating the common axle produces the shearing and cutting action needed to shred plastic.

On version one of the shredder, each blade had two hooked teeth, and the whole cutting head was made from relatively thick steel. When driven by a NEMA 34 stepper — an admittedly odd choice but it’s what they could get quickly — through a 50:1 planetary gearbox, the shredder certainly did the business. The shreds were a little too chunky, though, so version two used thinner steel for the blades and gave the rotary blades more teeth. The difference was substantial — much finer shreds that were suitable for INJEKTO, their homebrew direct-feed injection molding machine.

There’s a lot to be said for closing the loop on plastics used in desktop manufacturing processes, and the team of SHREDII and INJEKTO stands to help the home gamer effectively reuse plastic waste. And while that’s all to the good, let’s face it — the oddly satisfying experience of watching a shredder like this chew through plastic like it isn’t even there is plenty of reason to build something like this.

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Hackaday Podcast 168: Math Flattens Spheres, FPGAs Emulate Arcades, And We Can’t Shake Polaroid Pictures

Join Hackaday Editor-in-Chief Elliot Williams and Staff Writer Dan Maloney as they review the top hacks for the week. It was a real retro-fest this time, with a C64 built from (mostly) new parts, an Altoids Altair, and learning FPGAs via classic video games. We also looked at LCD sniffing to capture data from old devices, reimagined the resistor color code, revisited the magic of Polaroid instant cameras, and took a trip down television’s memory lane. But it wasn’t all old stuff — there’s flat-packing a sphere with math, spraying a fine finish on 3D printed parts, a DRM-free label printer, and a look at what’s inside that smartphone in your pocket — including some really weird optics.

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 below!

Direct Download link.

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