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Musical Tesla Coils Perform Zelda
heychris writes "You've gotta love the Chicago Tribune's story on Tesla Coil hobbyists from the first sentence. 'Under a starry Saturday sky behind a Lake Zurich warehouse, three men unload a small flamethrower, electric cabling, neon-tube "light sabers," about 80 pounds of chain mail and two 7-foot devices that look like monster-movie props.' So what does one do with 1.6 million volts and a Tesla coil or two? Play 110dB music, of course."
Thanks for knocking the LHC offline AGAIN!
Isn't this more of a visualization than an instrument?
They have a similar setup every year at DragonCon in Atlanta during the "Mad Scientist's Ball". I've never actually been that that particular track due to some insane lines (queue up 2-3 hours early if you want to get into that one), but speaking to other attendees it's been pretty cool, and certainly is popular every year.
"People who think they know everything are very annoying to those of us who do."-Mark Twain
They're more like speakers than an instrument. He's not "playing" them so much as they're just outputting a pre-programmed song. The act is just for entertainment.
"People who think they know everything are very annoying to those of us who do."-Mark Twain
There are likely only about 1,000 Tesla coil hobbyists worldwide.
There are quite a few more of us around as the Pupman mailing list http://www.pupman.com/ and the Geek Group http://www.thegeekgroup.org/ can attest.
Cannot find REALITY.SYS. Universe halted.
Because it's ubercool geekery?
Cannot find REALITY.SYS. Universe halted.
I've seen a couple of these videos, and it really doesn't have the staying power of the flaming tuba.
The coils are the actual sound output device. There are no speakers. There are only bolts of fantastic musical lightning.
There are dozens of videos on YouTube featuring this sort of thing, including people using such devices as guitar amplifiers.
Learning about brewing beer, by brewing beer.
I guarantee they aren't using 1.6 MW of power.
On the other hand, Tesla coils are all about the voltage.
... including people using such devices as guitar amplifiers.
Would that be an electric guitar?
Oh man that's a knee slapper!
Why not play Tesla instead?
They call it 'modulated thunder'. Thunder is just the noise produced by expanding gas heated by an electric discharge. The coils are actually being switched at several kHz, producing repeating 'thunder' at a frequency above the point where you stop hearing the individual claps, and instead hear a tone. It effectively is a low-mid range speaker.
Based on chatting with them when they did Penguicon in Michigan they use a control circuit to turn the coils on and off at a specific rate. This allows them to use the actual lightning breaks per second to generate sound. E.g. 128 breaks per second roughly equals a sound at 128 Hz.
When they were coming out here they asked us to provide 2 note MIDI files for playing. If I remember correctly the computer uses MIDI to drive the control circuitry that is fed optically (to avoid coupling to the coil itself) to the drive electronics in the coil. So not so much pre-programmed as interpreted.
Really neat technology they have put together and darned loud! I wonder if they ever built the other two notes they talked about building at Penguicon. Hearing 4 of those going in harmony would be sweet!
In this case I would not want to be the recipient of the electric bill. These are not your father's tesla coils. These are fairly low voltage very high current devices. The feed they got from the hotel at Penguicon a few years back was a 220V 50A and I remember them having an ammeter on the line to make sure they didn't exceed the rating and trip the circuit.
They run high current at lower voltage to be able to use solid state switching devices to drive the coil. No rotary spark gap here just a bunch of IGBTs and other fun silicon the size of your fist.
And I could do without breathing in all that ozone...
Two notes only. Each coil produces one note. At least that is how they were when I saw em a couple of years ago and the setup looks the same.
Sound in real life. Loud. Really freaking loud. These are 7 foot tall units putting out sparks around 7-10 feet controlled. Sound is point source to the coil it is originating from, sorta. The sorta being pretty much the area of the spark itself, so the source is wider than one would think. Highest and lowest dunno, though it had a very good audible range. The sound was a bit harsh due to the nature of how it was being generated and the noise from the bolts themselves.
All in all darned impressive. Very well done and they were very knowledgeable. I had the chance to sit down and chat with them for a little bit before they left and all I can say is "wow".
(I'm going to be a lameass and repost this that I wrote this seven years ago, when an "old busted TV" meant a CRT tube. For purposes of this discussion it still does)
You can easily make a Tesla coil if you have an old busted TV to rip apart. In general, the older and bigger the TV is, the better. And color TVs are better than black and white. This won't be a *great* Tesla coil, but it will throw a spark a few inches long and you can do all the standard Tesla coil tricks with it (St. Elmo's fire, etc.) without investing too much time or money.
Yank the flyback transformer out of the TV, and discard all its primary windings. Keep the big high voltage secondary winding (the one with the zillions of turns). It's usually encased in rubber and may look like a big rubber wheel. Its main lead has really thick insulation and connects to the side of the picture tube (where it looks like a stethoscope). The other lead (the ground) won't be as heavily insulated.
The only other parts you need are two NPN power transistors (2N3055), two 5W power resistors (20 ohm and 200 ohm), some wire, and a good supply of DC current (12-24 V). The circuit is a piece of cake. The first time I did it, I put the whole thing together with alligator clips.
This circuit has two primary windings around the flyback transformer core. The power winding is 8 turns, with a tap in the middle. The feedback winding is smaller (4 turns), also with a tap in the middle. The power winding leads connect to the collector leads on the transistors, with the center tap going to the +24 V DC power source. The feedback winding leads connect to the gate leads, with the center tap there going to +2-3 V DC (connect the resistors in series across the DC power to get the lower voltage in between). The emitter leads are grounded.
As current flows through one transistor, the changing field in the core induces a voltage in the feedback windings that turns that transistor off and the other one on. Then current flows the other way, and the same thing happens in reverse. So the circuit tunes itself to the proper frequency. But it also means that the first time you power it up you run a 50-50 chance of connecting the leads to the wrong transistor gates, in which case you get a stable DC circuit. So if it doesn't work the first time, try exchanging the gate leads.
This circuit is fairly well known, and doing a Google search for "flyback" and "Tesla" I found a schematic [aaroncake.net] for it right away. The guy mentions on that page that the transistors get really hot and he is not kidding- they do. Don't leave it running for more than a minute without a heat sink. The RF noise generated by Tesla coils is incredible, so expect to generate some interference. They make lots of smelly ozone. And if you let a spark go through paper, you can start a fire so be careful.
If you're lucky you can get 20-30 kV, which throws a purple spark a couple inches. (I only got about 4 kV out of mine- the spark was about a half inch long.) Pick up a neon bulb when you're at Radio Shack- these light up if they're around. If you touch one terminal of a fluorescent to ground then half of it will glow brightly between that end and the place you are holding it. The effect on a candle flame is interesting. Don't stick your bare finger near it because the spark does hurt if it hits unprotected skin. But if you hold a metal object and use that to touch it, you don't feel a thing (it's high frequency AC). Cool tricks include having sparks jump from the coil to a metal object in your hand, having sparks jump from a metal object in your other hand to ground (even a lousy ground), and having fluorescent tubes glow softly if you hold them in your other hand.
And if frequency sweeps are possible, then FM synthesis should be possible.
And if FM is possible then the DOOM soundtrack can be played. (!)
True confidence comes not from realising you are as good as your peers, but that your peers are as bad as you are.