How To Make A Pilotron, The Forgotten Tube

The vacuum tube is largely ignored in modern electronic design, save for a few audio applications such as guitar and headphone amps. The transistor is smaller, cheaper, and inordinately easier to manufacture. By comparison, showing us just how much goes into the manufacture of a tube, [glasslinger] decided to make a wire-element pilotron – from scratch!

To say this is an involved build is an understatement. Simply creating the glass tube itself takes significant time and skill. [glasslinger] shows off the skills of a master, however – steadily working through the initial construction, before showing off advanced techniques necessary to seal in electrodes, produce the delicate wire grid, and finally pull vacuum and seal the tube completely.

The project video is an hour long, and no detail is skipped. From 2% thoriated tungsten wire to annealing torches and grades of glass, it’s all there. It’s enough that an amateur could reproduce the results, given enough attempts and a complete shop of glassworking equipment.

The pilotron may be a forgotten design, but in 2018 it once again gets its day in the sun. Overall, it’s a testament to [glasslinger]’s skill and ability to be able to produce such a device that not only looks the part, but is fully functional on an electronic level, as well.

There’s a few people out there still building valves the old fashioned way, and we’d love to see more – tip ’em if you got ’em. Video after the break.

[Thanks to Morris for the tip!]

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The Precise Science Of Whacking A Wine Glass

It’s common knowledge that tapping a wine glass produces a pitch which can be altered by adjusting the level of the tipple of choice inside. By filling twelve glasses with different amounts of liquid and tuning them to the twelve notes of the scale, it’s possible to make a one-octave instrument – though the speed and polyphony are bottle-necked by the human operator. If you think it sounds like a ripe project for automation, you’re correct: [Bitluni’s lab] has done what needed to be done, and created a MIDI instrument which plays the glasses using mallets.

Electronically it’s a simple build – some 12 V solenoids driven by MOSFETs, with an Arduino in charge. For the mechanical build, a 3D printer proved very useful, as each mallet could be made identical, ensuring a consistent tone across all glasses. Rubber covers printed in flexible filament were fitted to reduce the overtones and produce a clearer sound. [Bitluni] also utilised different types of glasses for the low and high pitches, which also helped to improve the clarity of the tone.

MIDI is of course the perfect protocol for this application; simple, lightweight and incredibly widely used, it’s the hacker’s delight for projects like this. The instrument can perform pre-programmed sequences, or be played live with a MIDI controller. Both of these are shown in the video after the break – stick around for a unique rendition of Flight Of The Bumblebee. For a more compact wine glass based music creation solution, we recommend this nifty project, which alters pitch using a water balloon raised and lowered into the glass by a servo.  Continue reading “The Precise Science Of Whacking A Wine Glass” →

An Artsy And Functional LED Filament Lamp

Some projects end up being more objet d’art than objet d’utile, and we’re fine with that — hacks can be beautiful too. Some hacks manage both, though, like this study in silicon and gallium under glass that serves as a bright and beautiful desk lamp.

There’s no accounting for taste, of course, but we really like the way [commanderkull]’s LED filament lamp turned out, and it’s obvious that a fair amount of work went into it. Five COB filament strips were suspended from a lacy frame made of wire, which also supports the custom boost converter needed to raise the 12-volt input to the 60 volts needed by the filaments. The boost converter is based on the venerable 555 timer chip, which sits in the middle of the frame suspended by its splayed-out legs and support components. The wooden base sports a few big electrolytics and some hand-wound toroidal inductors, as well as the pot for adjusting the lamp’s brightness. The whole thing sits under a glass bell jar, which catches the light from the filaments and plays with it in a most appealing way.

There’s just something about that dead bug building technique that we love. We’ve seen it before — this potentially dangerous single-tube Nixie clock comes to mind — but we’d love to see it done more.

[via r/electronics]

What’s The Deal With Transparent Aluminum?

It looks like a tube made of glass but it’s actually aluminum. Well, aluminum with an asterisk beside it — this is not elemental aluminum but rather a material made using it.

We got onto the buzz about “transparent aluminum” as a result of a Tweet from whence the image above came. This Tweet was posted by [Jo Pitesky], a Science Systems Engineer at the Jet Propulsion Lab in Pasadena. [Jo] reported that at a recent JPL technology open house she had the chance to handle a tube of material that looks for all the world like a section of glass tubing, but was billed as transparent aluminum. [Jo] tweeted this because it was an interesting artifact that few people get to play with and she’s right, this is fascinating!

The the material itself is intriguing, and I immediately had practical questions like what is this stuff? What is it good for? How is it made? And is it really aluminum rendered transparent by some science fiction process?

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Vacuum Molding With Kitchen Materials

Vacuum pumps are powerful tools because the atmospheric pressure on our planet’s surface is strong. That pressure is enough to crush evacuated vessels with impressive implosive force. At less extreme pressure differences, [hopsenrobsen] shows us how to cleverly use kitchen materials for vacuum molding fiberglass parts in a video can be seen after the break. The same technique will also work for carbon fiber molding.

We’ve seen these techniques used with commercially available vacuum bags and a wet/dry vac but in the video, we see how to make an ordinary trash bag into a container capable of forming a professional looking longboard battery cover. If the garbage bag isn’t enough of a hack, a ball of steel wool is used to keep the bag from interfering with the air hose. Some of us keep these common kitchen materials in the same cabinet so gathering them should ’t be a problem.

Epoxy should be mixed according to the directions and even though it wasn’t shown in the video, some epoxies necessitate a respirator. If you’re not sure, wear one. Lungs are important.

Fiberglass parts are not just functional, they can be beautiful. If plastic is your jam, vacuums form those parts as well. If you came simply for vacuums, how about MATLAB on a Roomba?

Thank you [Jim] who gave us this tip in the comments section about an electric longboard.

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The Chemistry And Engineering Of DIY Photochromic Glass

[Ben Krasnow] is no stranger to exploring the more arcane corners of hackerdom, and the latest video on his “Applied Science” channel goes into a field few DIYers have touched: homemade glass, including the photochromic variety.

That DIY glassmaking remains a largely untapped vein is not surprising given what [Ben] learned over the last months of experimenting. With searing temperatures bordering on the unobtainable, volatile ingredients that evaporate before they can be incorporated, and a final product so reactive that a platinum crucible is the best vessel for the job, glassmaking is not easy, to say the least. Glassmaking doesn’t scale down from an industrial process very well, it seems. Nonetheless, [Ben] came up with a process that could be replicated using common enough ingredients and a simple electric kiln modded with a PID controller for pinpoint temperature setting. And while Luxottica has nothing to worry about yet, he did manage to get some clearly if subtly photochromic samples, despite the challenges.

Without a doubt, [Ben] crossed over into “mad scientist” territory a while back, and we think it’s great. What other way is there to describe a guy who has an electron microscope, a high-power ruby laser, a CT scanner, and a cookie making robot in his basement? Whatever you call it, we like the results.

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What Would Sherlock Print, If Sherlock Printed In SLA Resin?

Resin printing — or more appropriately, stereolithography apparatus printing — is a costly but cool 3D printing process. [Evan] from [Model3D] wondered if it was possible to produce a proper magnifying glass using SLA printing and — well — take a gander at the result.

A quick modeling session in Fusion 360 with the help of his friend, [SPANNERHANDS 3D Printing] and it was off to the printer. Unfortunately, [Evan] learned a little late that his export settings could have been set to a higher poly count — the resultant print looked a little rough — but the lens would have needed to be sanded anyway. Lucky coincidence! After an eight hour print on his Peopoly Moai using clear SLA resin, [Evan] set to work sanding.

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