Retrotechtacular: Nuvistor, Vacuum’s Last Gasp

July 21, 2021 by 51 Comments

In 2021 all our electronics are solid state, in that they exclusively use semiconductor devices as their active components. Some of us may experiment with vacuum tubes, but only for curiosity or aesthetic purposes. Semiconductors have overtaken vacuum devices in all but the rarest of niche applications due to their easier design requirements, greater reliability, lower cost, and increased performance.

It was not always this way though, and there was a period at the start of the semiconductor era when transistors and vacuum tubes existed together side-by-side and competed directly. Vacuum tube manufacturers continued to create new devices into the 1970s, and in doing so they pushed the boundaries of their art in unprecedented directions. [David W Knight] has a page dedicated to the Nuvistor, something his calls the “final evolution of the thermionic valve”. His comparison photo seen above shows a Nuvistor on the left — a miniature vacuum tube you’ve likely never seen before.

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Stop Touching My Face

July 13, 2021 by 12 Comments

We all have a habit or two that we’re not terribly proud of and have probably thought of any number of ways to help rid ourselves of them. Well, [Friedlc] wondered if he could create a mechanism that would get him to stop touching his face using a bit of negative conditioning. He rigged up a head brace that slaps his forehead whenever reaching for his face.

The first thing he needed to do was to detect a hand approaching his face. He decided to use a few cheap IR motion sensors he had laying around but noted they had a few limitations. He had a tough time tuning the sensitivity of the motion sensors to prevent false positives and they were completely useless in direct sunlight as the sun’s radiation saturated the photodetector. Despite these problems, [Friedlc] figured he would mostly need his device indoors so he stuck with the IR detectors.

For the “hitter” as he called it, he thought of a few different ideas. Maybe a rotating drum with a flap that would hit his hand or maybe a hitting arm on a bar linkage. He admitted that his rudimentary mechanical design knowledge made thinking of the perfect “hitter” a bit challenging, but like any good hacker, [Friedlc] just kept working at it. He decided on using a cam mechanism which allowed him to separate the motor from the hitting action. This choice actually put a lot less load on the motor which kept the motor from stalling and giving him other kinds of trouble.

[Friedlc] was pretty proud of his invention and noted that it really helped him stop touching his face as the successive strikes to the head were definitely quite a deterrent. This certainly isn’t the first time we’ve seen a Pavlovian Conditioning project on Hackaday. We could probably all use a bit of help curing a few bad habits. But maybe you prefer positive reinforcement instead.

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The Trouble With Hubble: Payload Computer Glitch Stops Science At The Space Observatory

July 2, 2021 by 21 Comments

The Hubble Space Telescope’s remarkably long service life and its string of astonishing contributions to astronomy belie its troubled history. Long before its launch into low Earth orbit in 1990, Hubble suffered from design conflicts, funding and budgetary pressures, and even the death of seven astronauts. Long delayed, much modified, and mistakenly sent aloft with suboptimal optics, Hubble still managed to deliver results that have literally changed our view of the universe, and is perhaps responsible for more screensaver and desktop pictures than any other single source.

But all of that changed on June 13 of this year, when Hubble suffered a computer glitch that interrupted the flow of science data from the orbiting observatory. It’s not yet clear how the current issue with Hubble is going to pan out, and what it all means for the future of this nearly irreplaceable scientific asset. We all hope for the best, of course, but while we wait to see what happens, it’s worth taking the opportunity to dive inside Hubble for a look at its engineering and what exactly has gone wrong up there.

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Good Enough For The Spruce Goose, Good Enough For Satellites

June 22, 2021 by 31 Comments

Wood products have a long history in aviation even though modern materials have eclipsed them in many areas. But lately we’ve noticed several plywood satellites, including this one the ESA plans to launch. The WISA Woodsat is a test of WISA plywood, a particular brand made in Finland to show how it can withstand the orbital environment.

Why not? Plywood is cheap and easy to form. You probably don’t want to make a pressure vessel with it, but most satellites don’t need that anyway.

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Hackaday Podcast 123: Radioactive Rhinos, Wile E. Coyote Jetpack, Radio Hacks 3-Ways, And Battery Welders On The Spot

June 18, 2021 by No comments

Hackaday’s Mike Szczys is taking a bit of vacation this week, so Elliot is joined by Staff Writer Dan Maloney to talk about all the cool hacks and great articles that turned up this week. Things were busy, so there was plenty to choose from, but how would we not pick one that centers around strapping a jet engine to your back to rollerskate without all that pesky exercise? And what about a light bulb that plays Doom – with a little help, of course. We’ll check out decals you can make yourself and why the custom keyboard crowd might want to learn that skill, learn about the other “first computer”, and learn how a little radiation might be just what it takes to save an endangered species.

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 (55 MB or so.)

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Digital X-Ray Scanner Teardown Yields Bounty Of Engineering Goodies

June 14, 2021 by 12 Comments

We’ll just go ahead and say it right up front: we love teardowns. Ripping into old gear and seeing how engineers solved problems — or didn’t — is endlessly fascinating, even for everyday devices like printers and radios. But where teardowns really get interesting is when the target is something so odd and so specialized that you wouldn’t normally expect to get a peek at the outside, let alone tramp through its guts.

[Mads Barnkob] happened upon one such item, a Fujifilm FCR XG-1 digital radiography scanner. The once expensive and still very heavy piece of medical equipment was sort of a “digital film system” that a practitioner could use to replace the old-fashioned silver-based films used in radiography, without going all-in on a completely new digital X-ray suite. It’s a complex piece of equipment, the engineering of which yields a lot of extremely interesting details.

The video below is the third part of [Mads]’ series, where he zeroes in on the object of his desire: the machine’s photomultiplier tube. The stuff that surrounds the tube, though, is the real star, at least to us; that bent acrylic light pipe alone is worth the price of admission. Previous videos focused on the laser scanner unit inside the machine, as well as the mechatronics needed to transport the imaging plates and scan them. The video below also shows experiments with the PM tube, which when coupled with a block of scintillating plastic worked as a great radiation detector.

We’ve covered a bit about the making of X-rays before, and a few of the sensors used to detect them too. We’ve also featured a few interesting X-ray looks inside of tech, from a Starlink dish to knock-off adapters.

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Rhisotope: Addressing Poaching By Making Rhinoceros Horns Radioactive

June 14, 2021 by 52 Comments

There is no question that poaching has become an existential threat to the five species of rhinoceros alive today. Even the wildlife reserves where most rhinos live struggle to provide protection from the wanton and cruel poaching of the world’s last remaining rhinos.

Poachers are generally looking to sell the horns which consist of pure keratin, the same material that makes up our fingernails and hair. Rhino horns have seen a big rise in demand the past decades, with a black market in Vietnam representing the biggest buyers, primarily for use in fever and other medicines, as well as for processing into carved trinkets. This has contributed to a further rhino population collapse. Statistics from 2017 show about 18,000 white rhinos and fewer than 5,500 black rhinos remaining. Recently, the northern white rhino population in Africa went effectively extinct with the death of the last known male individual.

Clearly, if we wish to prevent extinction, we need to deal with poaching. The latest suggestion here is part of the Rhisotope project. This would make rhino horns radioactive, but how exactly would doing so prevent poaching? Let’s take a look.

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