Supercon 2022: Samy Kamkar’s Glowing Breath

January 10, 2023 by Elliot Williams 6 Comments

Sometimes the journey itself is the destination. This one started when [Samy] was 10 and his mom bought a computer. He logged on to IRC to talk with people about the X-Files and was WinNuked. Because of that experience, modulo a life of hacking and poking and playing, the talk ends with a wearable flex-PCB Tesla coil driving essentially a neon sign made from an ampule of [Samy]’s own breath around his neck. Got that? Buckle up, it’s a rollercoaster.

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Tesla Coil Makes Sodium Plasma

November 26, 2022 by Al Williams 11 Comments

Looking for a neat trick to do with your Tesla coil? [The Action Lab] uses his coil to make a metal plasma — in particular, sodium. You can see the results in the video below.

To create a metal plasma, you need a metal vapor and sodium can create a vapor at a relatively low temperature, especially in a vacuum. The resulting glow is pretty to look at, but you will need a bit of lab gear to pull it off.

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Enjoy The Beauty Of Corona Discharge With This Kirlian Photography Setup

October 12, 2022 by Dan Maloney 12 Comments

In our age of pervasive digital media, “pics or it didn’t happen” is a common enough cry that most of us will gladly snap a picture of pretty near anything to post online. So if you’re going to take a picture, it may as well be as stunning as these corona discharge photographs made with a homebrew Kirlian photography rig.

We know, Kirlian photography has a whole “woo-woo” vibe to it, associated as it has been with paranormal investigations and the like. But [Hyperspace Pirate] isn’t flogging any of that; in fact, he seems way more interested in the electronics of the setup than anything else. The idea with Kirlian photography is basically to capacitively couple a high-voltage charge across a dielectric, which induces an electrostatic discharge to a grounded object. The result is a beautiful purple discharge, thanks to atmospheric nitrogen, that outlines the object being photographed.

[Pirate]’s first attempt at a Kirlian rig used acrylic as a dielectric, which proved to be susceptible to melting. We found this surprising since we’ve seen [Jay Bowles] successfully use acrylic for his Kirlian setup. Version 2 used glass as a dielectric — right up until he tried to drill a fill port into the glass. (Important safety tip: don’t try to drill holes in tempered glass.) Version 3 used regular glass and a 3D-printed frame to make the Kirlian chamber; filled with saltwater and charged up with a homebrew Tesla coil, the corona discharge proved enough to char fingertips and ignite paper. It also gave some beautiful results, which can be seen starting at around the 7:40 mark in the video below.

We loved the photos, of course, but also appreciated the insights into the effects of inductance on the performance of this setup. And that first homebrew flyback transformer [Hyperspace Pirate] built was pretty cool, too.

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Junkbox Build Keeps Tesla Coils Perfectly Varnished

August 9, 2022 by Dan Maloney 21 Comments

Admittedly, not a lot of people have a regular need to varnish coils. It’s mainly something that Tesla coil builders and other high-voltage experimenters are concerned with. But since that group probably constitutes a not insignificant fraction of the Hackaday audience, and because there are probably more applications for this homebrew coil varnishing setup, we figured it would be a good idea to share it.

For [Mads Barnkob], coil maintenance isn’t something to take lightly. If you check out his Kaizer Power Electronics channel on YouTube, you’ll see that he has quite a collection of large, powerful Tesla coils, some of which are used for demos and shows, and others that seem to be reserved mainly for blowing stuff up. To prevent one of his coils from joining the latter group, keeping the coat of insulating varnish on the secondary coil windings in tip-top condition is essential.

The setup seen in the video below helps with that tedious chore. Built entirely from scraps and junk bin parts, the low-speed, low-precision lathe can be set up to accommodate coils of all sizes. In use, the lathe turns the coil very slowly, allowing [Mads] to apply an even coat of varnish over the coil surface, and to keep it from sagging while it dries.

[Mads]’ setup is probably not great for coil winding as it is, but for coil maintenance, it’s just the thing. If your needs are more along the lines of a coil winder, we’ve got a fully automated winder that might work for you.

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Hackaday Prize 2022: A Plasma Tweeter For Ultimate Clarity

August 8, 2022 by Jenny List 18 Comments

In the world of audio there are a huge variety of esoteric technologies which are rarely seen. One such is the plasma tweeter, a type of loudspeaker which generates sound by modulating a small electrical discharge. The benefit of this design comes in its delivering the closest possible to a point audio source, in effect the theoretical ideal speaker for treble frequencies. They’re a little hazardous due to the voltage but aren’t too difficult to make, as demonstrated by [Mircemk] whose version uses a recycled power pentode tube — which is how it showed up in the Hack it Back round of the Hackaday Prize.

It can be thought of as a cousin of the Tesla coil, with the same resonant oscillator but no capacity hat. Instead the top of the coil ends in a point, from which in the perfect speaker a ball of plasma replaces the Tesla’s impressive sparks. In this case the pentode is joined by a high-voltage TV line output transistor as a bias supply, which is in turn modulated with the audio through a small amplifier. It sometimes needs the plasma teasing out of it through discharge to a screwdriver, but the result is a very effective and clear plasma tweeter.

If plasma tweeters interest you, we’ve featured them before.

High Tech Pancake Tesla Coil Brings The Lightning

March 18, 2022 by Tom Nardi 4 Comments

For several years now we’ve been following [Jay Bowles] as he brings high-voltage down to Earth on his Plasma Channel YouTube channel. From spark gaps made of bits of copper pipe to automotive ignition coils driven by the stalwart 555 timer, he’s got a real knack for keeping his builds affordable and approachable. But once in a while you’ve got to step out of your comfort zone, and although the dedicated DIY’er could still replicate the solid state “pancake” Tesla coil he documents in his latest video, we’d say this one is better left for the professionals.

The story starts about nine months ago, when [Jay] was approached by fellow YouTuber [LabCoatz] to collaborate on a PCB design for a solid state Tesla coil (SSTC). Rather than a traditional spark gap, a SSTC uses insulated-gate bipolar transistors (IGBTs) triggered by an oscillator, which is not only more efficient but allows for fine control of the primary coil. The idea was to develop an AC-powered coil that was compact, easy to repair, and could be controlled with just a couple dials on the front panel. The device would also make use of an antenna feedback system that would pick up the resonant frequency of the secondary coil and automatically adjust the IGBT drive to match.

Being considerably more complex than many of the previous builds featured on Plasma Channel, it took some time to work out all the kinks. In fact, the majority of the video is [Jay] walking the viewer through the various failure modes that he ran into while developing the SSTC. Even for somebody with his experience in high-voltage, there were a number of headscratchers that had to be solved.

For example, the first version of the design used metal bolts to attach the primary and secondary coils, until he realized that was leading to capacitive coupling and replaced them with acrylic blocks instead. If his previous videos surprised you by showing how easy it could be to experiment with high-voltages, this one is a reminder that it’s not always so simple.

But in the end [Jay] does get everything sorted out, and the results are nothing short of spectacular. Even on the lower power levels it throws some impressive sparks, but when cranked up to max, it offers some of the most impressive visuals we’ve seen so far from Plasma Channel. It was a lot of work, but it certainly wasn’t wasted effort.

Fascinated by the results, but not quite ready to jump into the deep end? This affordable and easy to build high-voltage generator featured on Plasma Channel back in 2020 is a great way to get started. If you still need more inspiration, check out the fantastic presentation [Jay] gave during the 2021 Remoticon.

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A Builders Guide For The Perfect Solid-State Tesla Coil

October 31, 2021 by Dave Rowntree 14 Comments

[Zach Armstrong] presents for your viewing pleasure a simple guide to building a solid-state Tesla coil. The design is based around a self-resonant setup using the UCC2742x gate driver IC, which is used in a transformer-coupled full-wave configuration for delivering maximum power from the line input. The self-resonant bit is implemented by using a small antenna nearby the coil to pick up the EM field, and by suitably clamping and squaring it up, it is fed back into the gate driver to close the feedback loop. Such a setup within reason allows the circuit to oscillate with a wide range of Tesla coil designs, and track any small changes, minimizing the need for fiddly manual tuning that is the usual path you follow building these things.

Since the primary is driven with IGBTs, bigger is better. If the coil is too small, the resonant frequency would surpass the recommended 400 kHz, which could damage the IGBTs since they can’t switch much faster with the relatively large currents needed. An important part of designing Tesla coil driver circuits is matching the primary coil to the driver. You could do worse than checkout JavaTC to help with the calculations, as this is an area of the design where mistakes often result in destructive failure. The secondary coil design is simpler, where a little experimentation is needed to get the appropriate degree of coil coupling. Too much coupling is unhelpful, as you’ll just get breakdown between the two sides. Too little coupling and efficiency is compromised. This is why you often see a Tesla coil with a sizeable gap between the primary and secondary coils. There is a science to this magic!

A 555 timer wired to produce adjustable pulses feeds into the driver enable to allow easily changing the discharge properties. This enables it to produce discharges that look a bit like a Van De Graaff discharge at one extreme, and produce some lovely plasma ‘fire’ at the other.

We’ve covered Tesla coils from many angles over the years, recently this plasma tweeter made sweet sounds, and somehow we missed an insanely dangerous Tesla build by [StyroPyro] just checkout that rotary spark gap – from a distance.

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