Little eBay Tesla Coil Gets an Upgrade

Like so many of the projects we feature, this one started with a cheap eBay module purchase. In this case, it was a little Tesla coil that made decent sized arcs but wasn’t quite good enough. The result was a super-sized solid state Tesla coil with better results and room to grow.

As [GreatScott!] discovered, the little eBay Tesla coil has a pretty neat design. The exciter is a Slayer circuit, a super simple one-transistor design. His reverse engineering revealed that the primary coil is simply a loop trace on the PCB under the secondary coil. Sadly, his attempt to replace the primary and reproduce the Slayer exciter resulted in anemic performance. What’s a hacker to do in that case except build a bigger coil? Much bigger — like “build your own winding jig” bigger. Twelve hundred secondary turns and an appropriately menacing-looking primary later, the results were — still anemic. It turns out the Slayer is just not up to the task. He turned to an inverter circuit that was previously used in a wireless energy transfer circuit, and we finally get to see a little of the Tesla coil magic. But wait! There’s more to come, as future videos will tweak the circuit and optimize the coil for better performance.

It’s no surprise that Tesla coils are a popular project around here, especially the musical kinds, from the tiny to the large. Music doesn’t seem to be on [GreatScott!]’s mind, though, and we’ll be watching with interest to see where he takes this build.

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That Sucks! Death of a Tesla Coil

[Electroboom] always has some entertaining videos. He recently tried to run his Tesla coil in a vacuum. The video shows some interesting results, along with his usual bleeped out expletives as he drills into his hand and suffers other indignities in the name of electronics.

Unfortunately, a bit of extra bolt caused the coil to arc internally, eventually leading to the impressive device shuffling off its mortal… um, well, let’s just say its untimely demise. Along the way, though, you get to see some interesting techniques for building a silicone seal for the vacuum chamber, and some neat Tesla coil tricks with a closed off syringe.

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Tesla Coil Powered Film Canister Gatling Gun

What do you get when you combine a Tesla coil, 315 film canisters and a fortune wheel? The answer is of course a film canister Gatling gun. [ScienceBob] has taken the simple film canister cannon hack to a whole new level. The idea is simple, the film canister has a lid that fits tight and allows pressure to build up, so if you fill it with alcohol vapor and ignite it with a spark gap, you get a small explosion that sends the can flying  away.

[ScienceBob] uses 21 rows of fifteen canisters each around the wheel. There is a spark gap for each canister, and all the spark gaps in the same row are in series. You need a lot of volts to turn on fifteen spark gaps, and that is why the Tesla coil is part of the game. When the outer end of the wire in one row passes near the Tesla coil, a spark jumps and fires all the spark gaps, igniting the alcohol vapor and fifteen cans are expelled from the wheel. The wheel rotates until all rows are fired.

While this nice piece of artillery is sure a lot of fun to fire, but don’t ask us to reload it! If you want more power, check this Gatling gun that fires crossbow bolts, or the Gatling water pistol.

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Teslaphoresis: Tesla Coil Causes Self-Assembly In Carbon Nanotubes

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This significant discovery in nanotechnology could also be the first practical use of a Tesla coil in modern times that goes beyond fun and education. A self-funded research team at Rice University has found that unordered heaps of carbon nanotubes will self-assemble into conductive wires when exposed to the electric field of a strong Tesla coil. The related paper by lead author and graduate student [Lindsey R. Bornhoeft], introduces the phenomenon as “Teslaphoresis”. Continue reading “Teslaphoresis: Tesla Coil Causes Self-Assembly In Carbon Nanotubes”

Sparklecon: Crappy Robots, Better Robots, Hammer Jenga, Tesla Coils

Last weekend was Sparklecon, the premier meetup in Southern California of dorks dorking around, fire, electricity, welding, and general mischief. Just imagine a party of a hundred or so like-minded individuals at a hackerspace. Now imagine the entire party is the after party. That’s a pretty good idea of what happened.

The event was held at the 23b shop in Fullerton, a true hackerspace tucked away in a small industrial park. The people at 23b are using their location to their advantage: no one in the neighborhood really cares what happens after 5pm on a Friday. This allows for some very loud, very bright, and very dangerous hijinks.

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There weren’t many pages missing from the Hackaday Omnibus donated to the 23b shop. Oddly, the only pages missing were the articles written by Benchoff.

There was something for everyone at Sparklecon, including:

  • Electric Pickle. Take a stick welder, and put a few hundred amps through a pickle. First, the pickle turns into a sodium light. Then, it turns into a carbon arc light. Best done after dark.
  • FPV drone racing. Flying around and crashing into trees in an abandoned lot. FPV from a few quads were projected onto the side of a building
  • Live music! Analog synths and Game Boys!
  • Tesla coils! This was a 300 amp monster, and completely analog. The spark gap was impressive by itself, but it gets really cool when you steal a fluorescent light from a fixture and stand 20 feet away from the Tesla coil.
  • Hammer Jenga! Cut some 2x4s up and make a tower of Jenga. Get a hammer, some colorful commentators,  a dozen people, and make some competition brackets. Hackaday’s own [Jasmine] was the first champion of the night.
  • Sparklebot Death Battle! It’s like BattleBots, only things break more often and we don’t have [Bil Dwyer].
  • Hebocon! Battling robots, but much crappier than the Sparklebot Death Battle. These robots broke more often.

The main event was, of course, Sparklecon’s own version of Battlebots. There were only four competitors the entire night, but the competition was fierce.

Three of the bots were wedge designs, in keeping with the ramp-ification of battling robots. The lone exception to this was [Charlie]’s Slow Bot, a cube design equipped with a spinning steel blade. The blade moves fast, but Slow Bot doesn’t. It’s a purely defensive design, meant to destroy bots trying for an easy kill. The test video of Slow Bot can be seen here:

The first fight of Slow Bot did not live up to the hype, unfortunately. After Slow Bot’s primary weapon got up to speed, the opposing bot moved in for the kill. The bolts on Slow Bot‘s blade sheared, ending the match, and leaving five or six people looking around the 23b shop for M5 bolts, or some larger bolts and a tap.

Is it all hilarously unsafe? Well, there were some plexiglas shields in front of the crowd, and most people viewed the fights on the projector beaming against the wall, anyway.

Is it worth it to go to Sparklecon? If you like dangerous experiments, soldering wires directly onto AA batteries, fire, electricity, electromagnetic fields, broken robots, and hanging out by a fire, yes. It’s a party at a proper hackerspace, making it the best kind of party ever. If history repeats itself, there will also be an afterparty at 23b following the LayerOne conference in May.

The Best Badges Of The SuperCon

A few weeks ago, we took a look at the best badge hacks at the Hackaday Supercon. These were the best badge hacks anyone has ever seen – including what comes out of DEF CON and the SDR badge from the latest CCC. I’m ascribing this entirely to the free-form nature of the badge; give people a blank canvas and you’re sure to get a diverse field of builds. Now it’s time to take a look at the cream of the crop, hear what the jolly wrencher sounds like, and how to put 1000 Volts in a badge.

There were three categories for the badge hacking competition at the SuperCon – best deadbug, best blinky, and most over the top. A surprising number of people managed to solder, glue, and tape some components to a the piece of FR4 we used as a conference badge, but in the end, only three would win.

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Low-Voltage Tesla Coil Uses a Relay Instead of a Spark Gap

[Teodor] writes in with a unique Tesla coil he designed and built. Unlike most Tesla coils, [Teodor]’s design is able to run with a fairly low input voltage because it doesn’t use a static spark gap like most Tesla coils. Instead, his coil uses a relay in place of a spark gap.

[Teodor] built his coil using leftover components from his old school, making good use of some parts that might have otherwise been thrown away. The most critical component of his circuit, the relay, is just a standard normally-closed relay that is rated at 20A. [Teodor] wired the relay so that it energizes its own coil whenever it is shut. This causes the relay to briefly open every time the coil is energized, creating a resonant circuit. The resonant circuit charges a tank capacitor and places it in series with the primary coil inductor every time the relay closes, forming the tank circuit of his design.

With [Teodor]’s design, the resonant frequency of the secondary is nearly identical to that of the primary. This creates a significant voltage boost, helping produce very high voltages from such a low input voltage. The only downside to this design that [Teodor] recently discovered is that the relay contacts get red-hot after a few minutes of operation. Not optimal, but it still works! Check out [Teodor]’s writeup for more details and instructions on how to build your own.