Creating A Custom Engagement Ring With 3D-Printing

January 5, 2020 by Dan Maloney 11 Comments

Even if you’re pretty sure what the answer will be, a marriage proposal is attended by a great deal of stress to make the event as memorable and romantic as possible. You’ve got a lot of details to look after, not least of which is the ring. So why not take some of the pressure off and just 3D-print the thing?

No, a cheesy PLA ring is probably not going to cut it with even the most understanding of fiancees, and that’s not at all what [Justin Lam] did with this DIY engagement ring. He took an engineer’s approach to the problem – gathering specs, making iterative design changes in Fusion 360, and having a prototype ring SLA printed by a friend. That allowed him to tweak the design before sending it off to Shapeways for production. We were surprised to learn that jewelry printing is a big deal, and Shapeways uses a lost-wax process for it. First a high-resolution wax SLA printer is used to make a detailed positive, which is then used to make a plaster mold. The mold is fired to melt the wax, and molten gold is poured in to make the rough casting, which is cleaned and polished before shipping.

Once he had the ring, [Justin] watched a few jewelry-making videos to learn how to set the family heirloom stone into the bezel setting; we admit we cringed a bit when he said he used the ~~blade~~ shaft of a screwdriver to crimp the edge of the bezel to the stone. But it came out great, even if it needed a bit of resizing. The details of the proposal are left to the romantically inclined, but TL;DR – she said yes.

Congratulations to the happy couple, and to [Justin] for pulling off a beautiful build. Most of our jewelry hacks are of the blinkenlight variety rather than fine jewelry, although we have featured a machinist’s take on the subject before.

The Quadratic Equation Solution A Few Thousand Years In The Making

January 3, 2020 by Al Williams 38 Comments

Everyone learns (and some readers maybe still remember) the quadratic formula. It’s a pillar of algebra and allows you to solve equations like Ax²+Bx+C=0. But just because you’ve used it doesn’t mean you know how to come up with the formula itself. It’s a bear to derive so the vast majority of us simply memorize the formula. A Carnegie Mellon mathematician named Po-Shen Loh didn’t expect to find a new way to derive the solution when he was reviewing math materials for middle school use to make them easier to understand. After all, people have been solving that equation for about 4,000 years. But that’s exactly what he did.

Before we look at the new solution, let’s talk about why you want to solve quadratic equations. They are used in many contexts. In ancient times you might use them to determine how much more crop to grow to cover pay tax payments without eating in to the crop you needed to subsist. In physics, it can describe motion. There’s seemingly no end to how many things you can describe with a quadratic equation.

Babylonians, in particular, would solve simultaneous equations to find the roots of a quadratic. Egyptians, Grecians, Indians, and Chinese peoples used graphical methods to solve the equations. The entire history is a bit much to get into, but still a great read. For this article, let’s dig into how the new derivation was discovered.

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Roll The Bones Chernobyl Style

January 2, 2020 by Dan Maloney 18 Comments

We’re suckers for the Fallout aesthetic, so anything with a post-apocalyptic vibe is sure to get our attention. With a mid-century look, Nixie tubes, a brushed metal faceplate, and just a touch of radioactivity, this quantum random number generator pushes a lot of design buttons, and it pushes them hard.

Charmingly named “Chernobyl Dice”, this little gadget comes to us from [Nathan Griffith], and appears to be one of those “Why not?” builds we love so much. The heart of any random number generator is a source of entropy, for which [Nathan] chose to use six slightly radioactive uranium glass marbles. Those feature prominently in the front panel of the device, occasionally made to fluoresce with a few UV LEDs just because it looks cool. A Geiger tube inside the case is used to look for decay events from the marbles every millisecond. After some adjustment for the bias toward zeroes due to the relative rarity of decay events, the accumulated bits are displayed on eight Nixies. The box can be set to generate a stream of random numbers up to 31 bits long and send it over a USB port, or make random throws of a die with a settable number of sides. And when it’s not doing random stuff, it can just be a cool Nixie clock.

There are lots of ways to generate the entropy needed for truly random number generation, from a wall of lava lamps to bubbles in a fish tank. They’ve all got style, but something about this one just works.

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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!