Foam Board, Old Electronics, And Imagination Make Movie Magic

December 31, 2019 by Dan Maloney 11 Comments

When it comes to building sets and props for movies and TV, it’s so easy to get science fiction wrong – particularly with low-budget productions. It must be tempting for the set department to fall back on the “get a bunch of stuff and paint it silver” model, which can make for a tedious experience for the technically savvy in the audience.

But low-budget does not necessarily mean low production values if the right people are involved. Take [Joel Hartlaub]’s recent work building sets for a crowdfunded sci-fi film called Infinitus. It’s a post-apocalyptic story that needed an underground bunker with a Fallout vibe to it, and [Joel] jumped at the chance to hack the sets together. Using mainly vintage electronic gear and foam insulation boards CNC-routed into convincing panels, he built nicely detailed control consoles for the bunker. A voice communicator was built from an old tube-type table radio case with some seven-segment displays, and the chassis of an old LCD projector made a convincing portable computer terminal. The nicest hack was for the control panel of the airlock door. That used an old TDD, or telecommunications device for the deaf. With a keyboard and a VFD display, it fit right into the feel of the set. But [Joel] went the extra mile to make it a practical piece, by recording the modulated tones from the acoustic coupler and playing them back, to make it look as if a message was coming in. The airlock door looks great too.

Like many hacks, it’s pretty impressive what you can accomplish with a deep junk pile and a little imagination. But if you’ve got a bigger budget and you need some computer displays created, we know just the person for the job.

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Building A Spinning Moiré Effect Lamp

December 28, 2019 by Lewin Day 7 Comments

A concise, comical explanation of Moiré patterns, via XKCD.

Moiré patterns are interference patterns created when grids of different size or alignment are placed over each other. You’ve probably seen these when photographing a TV screen or looking through a pair of windows screens at the same time. [ChrysN] put the effect to work with this spinning Moiré lamp build.

It’s a build that can be achieved with scrap-bin components. An LED-encrusted PC cooling fan is used as the base of the lamp, fitted with Sugru bumpers to hold a cheap glass vase. A line pattern is then printed on to paper, rolled into a cylinder, and slid on to the fan to spin with the blades, inside the vase. Another line pattern is then printed on to a transparency (a printable transparent sheet for those who don’t remember overhead projectors) and slid around the outside of the vase. When powered up, the LEDs glow, and the fan spins, creating a hypnotizing moving moiré pattern.

It’s a simple but visually captivating build, and one that should keep you up at night thanks to the blue LEDs. Moiré patterns can do so much more though – they’re even put to work guiding ships. Video after the break.

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[Ben Krasnow]’s Take On DIY Air Bearings

December 28, 2019 by Dan Maloney 6 Comments

We’ve got to admit that watching [Ben Krasnow]’s new video on air bearings is tough. We found our eyes constantly checking the spherical air bearing in the foreground, which for the first eight minutes of the video just kept going. It was strangely hypnotic, and made it hard to concentrate on all the other cool stuff [Ben] was up to.

If the topic of air bearings seems familiar, it might be because we recently reported on DIY air bearings made from used EDM electrodes. [Ben] saw that too, and dusted off his old air bearing project. Literally, as it turns out, because the graphite blocks whose porosity and softness make them the perfect material for air bearings also makes for a dusty workshop. We’d recommend breathing protection of some sort while machining graphite. In addition to simple puck bearings, [Ben] came up with more complicated designs, including the aforementioned spherical bearing. He used the steel ball itself as a precision tool to grind the graphite out, first by coating it with abrasive and then by cutting grooves in it to act like a file. A cylindrical bearing was also cut, this time with sandpaper glued directly to the ground steel rod that would seat in the bearing.

[Ben]’s other innovation is vacuum preloading, where he applies both vacuum and pressure to the bearing plenum. The vacuum provides the force needed to capture the moving element while the pressure bears the load. It’s a careful balancing act, but it works well enough to capture the large steel ball and keep it turning effortlessly.

We really liked [Ben]’s take on air bearings, especially his thoughts on creating fully enclosed cylindrical bearings. Those could be useful for low-friction linear drives, and we look forward to seeing more on those.

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Replica Proton Pack Is A Great Halloween Build

December 14, 2019 by Lewin Day 2 Comments

Way back in 1984, the Ghostbusters defended New York City from an onslaught of supernatural phenomena. In their honor, [BALES] created this costume for Halloween, replete with an amazing replica proton pack.

(We know, this is a little late for Halloween 2019, but just think about how early you’re going to be for Halloween 2020!)

While not actually capable of trapping and harnessing entities from the spirit realm, the replica pack nonetheless is impressive. Constructed primarily from EVA foam and PVC pipe, it’s built on a custom built Alice pack frame to make it easy to carry. The cyclotron scores some LEDs, and EL wire completes the neutrino wand. A rough-and-ready paintjob make the gear look well used, and the laser-printed labels go a long way to completing the look.

[BALES] didn’t skimp on the clothing side either. The olive drab overalls, an embroidered patch, and belt were sourced from Amazon, and a custom name badge was produced to complete the ensemble. We’re sure the costume was an absolute hit at Halloween, and gives us plenty ideas of our own. It would pair well with this PKE meter that actually detects radiation, too!

Burning Propane Beautifully Illustrates How A Tesla Valve Works

December 13, 2019 by Dan Maloney 42 Comments

When you hear the name “Tesla”, chances are good that thoughts turn instantly to the company that’s trying to reinvent the motor vehicle and every industry that makes it possible. While we applaud the effort, it’s a shame that they chose to appropriate the surname of a Serbian polymath as their corporate brand, because old [Nikola] did so many interesting things in his time, and deserves to be remembered in his own right.

Take the Tesla valve. In essence a diode for fluids, the Tesla valve uses a tortuous path to allow flow in one direction but severely restrict it in the other. Understanding how it works isn’t necessarily intuitive, though, which is why [NightHawkInLight] chose to demonstrate the Tesla valve principle with exploding propane. It’s not new territory to him; we’ve covered his propane-powered rifle in the past.

The swirling blue and green flame front in those experiments make burning propane the perfect working fluid to demonstrate how the Tesla valve works. The video below tells the tale, with high-speed footage showing the turbulence that restricts the reverse flow. The surprise discovery is that in the forward direction, the burning gas actually seems to accelerate as it moves down the valve; hypersonic Tesla plasma cannon, anyone?

We’ve seen Tesla valves before, including one made from a “Shrinky Dink”. That did a pretty good job of visualizing the flow patterns that make the valve work, but there’s a huge showmanship gap between tiny channels filled with colored water and the explosive decomposition of a fuel-air mix. It’s a bit riskier, and standard “don’t try this at home” disclaimers apply, but luckily [NightHawkInLight] still has his eyebrows, so he must be doing something right.

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3D-Printer And CNC Make This Russian Calculator Bilingual

December 13, 2019 by Dan Maloney 11 Comments

Let’s be clear right up front: there are probably more obvious solutions to the problem of using a Russian calculator when you don’t speak Russian than printing new keys and engraving translated markings on them. But easy solutions are boring and generally considered beyond the scope of Hackaday articles, so let’s dive in.

They say that mathematics is the universal language, but that’s only true to an extent. Still, even with our ~~limited~~ non-existent Cyrillic skills, the Russian keyboard on this RPN calculator isn’t that hard to figure out. But as [Amen] points out, in the midst of fevered calculations, one prefers not to mentally translate Χ→П to STO or remember that В↑ is the Enter key. So he printed a set of replacements for the confusing keys from PLA. While pondering how to safely fixture such small parts for the later engraving step, [Amen] hit on a genius solution: move the print bed to the CNC router and fixture everything in one go. The resulting characters are large enough to be legible and deep enough to be filled with air-drying polymer clay for contrast. After sanding and polishing, the calculator looks like it came from the Министерство электронной промышленности that way.

Honestly, we’d love to get a look inside this calculator. The insides of Russian electronics can be fascinating, and we’ve even seen entire forums dedicated to decapping Russian parts. But we understand the desire to keep it intact.

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Are You Getting Your Money’s Worth From Threaded Inserts?

December 12, 2019 by Dan Maloney 14 Comments

Have you ever wondered whether it’s worth the time and expense to install threaded inserts into your 3D-printed projects? [Stefan] from CNC Kitchen did, and decided to answer the question once and for all, with science.

If this sounds familiar, it’s with good reason: we covered [Stefan]’s last stab at assessing threaded inserts back in March. Then, he was primarily interested in determining if threaded inserts are better than threads cut or printed directly into parts. The current work is concerned with the relative value of different designs of threaded inserts. He looked at three different styles of press-in inserts, ranging in price from pennies apiece to a princely 25 cents. The complexity of the outside knurling seems not to be correlated with the price; the inserts with opposed helical knurls seem like they’d be harder to manufacture than the ones with simple barbs on the outside of the barrel, but cost less. And in fact, the mid-price insert outperformed the expensive one in pull-out tests. Surprisingly, the cheapest inserts were actually far worse at pull-out resistance than printing undersized holes and threading an M3 screw directly into the plastic.

[Stefan] also looked at torque resistance, and found no substantial difference between the three insert types. Indeed, none of the inserts proved to be the weak point, as the failure mode of all the torque tests was the M3 bolt itself. This didn’t hold with the bolt threaded directly into the plastic, of course; any insert is better than none for torque resistance.

We enjoyed seeing [Stefan]’s tests, and appreciate the data that can help us be informed consumers. [John] over at Project Farm does similar head-to-head tests, like this test of different epoxy adhesives.

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