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Musical Tesla Coils Perform Zelda 82

Posted by CmdrTaco
from the nerds-with-time dept.
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."
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Musical Tesla Coils Perform Zelda

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  • by Anonymous Coward on Wednesday December 02, 2009 @12:52PM (#30299608)

    Thanks for knocking the LHC offline AGAIN!

  • I saw this in a hotel room in Nashville at Phreaknic. Or at least something very similar... loud as hell. Wicked cool though. Guy was running off of an mp3 player from what I understand.
    • Re: (Score:3, Insightful)

      by BHearsum (325814)

      Isn't this more of a visualization than an instrument?

      • Re: (Score:3, Informative)

        by MBGMorden (803437)

        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.

        • I don't know if it was "pre-programmed" or not. I got the impression that it was somehow detecting the beat of the music and then adjusting the voltage accordingly.
          • Re: (Score:2, Informative)

            by VanGarrett (1269030)

            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.

            • Re: (Score:3, Funny)

              by Firemouth (1360899)

              ... including people using such devices as guitar amplifiers.

              Would that be an electric guitar?

              Oh man that's a knee slapper!

          • Re:Saw this (Score:5, Informative)

            by Sly-Guy (2100) <mark@@@szlaga...net> on Wednesday December 02, 2009 @01:59PM (#30300472) Homepage

            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!

      • Re:Saw this (Score:4, Informative)

        by wagnerrp (1305589) on Wednesday December 02, 2009 @01:41PM (#30300226)
        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.
  • Now that's taking concert pyrotechnics to a new level!
  • DragonCon (Score:5, Interesting)

    by MBGMorden (803437) on Wednesday December 02, 2009 @12:56PM (#30299672)

    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.

    • They also show up every year at Duckon in Naperville, IL, in June. That show's held in the parking lot, so it's easy to get a huge crowd. It's tons of fun, you can really tell these guys are having a blast the whole time.
    • by guru42101 (851700)
      Arc Attack (the ones at DragonCon) put on a great show. The guys in the linked YouTube videos seem so boring compared to Arc Attack's personality.
  • Neat! I reside in Gurnee (about 15 minutes north of Lake Zurich). Wish I would have heard about this happening!
  • I like this one (Score:4, Informative)

    by TimeElf1 (781120) <<kennettb> <at> <gmail.com>> on Wednesday December 02, 2009 @01:02PM (#30299746) Homepage Journal
    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/ [pupman.com] and the Geek Group http://www.thegeekgroup.org/ [thegeekgroup.org] can attest.
  • dupe (Score:1, Offtopic)

    by t35t0r (751958)
    dupe
  • by addikt10 (461932) * on Wednesday December 02, 2009 @01:20PM (#30299978)

    I guarantee they aren't using 1.6 MW of power.

    On the other hand, Tesla coils are all about the voltage.

    • Really? I thought they were all about the size of the... uh ... sparks?
    • by LoRdTAW (99712)

      Yea the article got that wrong, but you could look at it from another angle: Depending on the capacitor value and voltage, you can have upward or greater than a 1MW discharge in the tank circuit. The formula: Joules = 1/2 * Vc^2 * C (Vc is the capacitor voltage and C is capacitance in farads) dictates the amount of energy stored in the capacitor. If a capacitor holding 1000 joules of electrical energy is discharged in one millisecond you have a 1MW pulse. Tesla coils are pulsed resonant transformers. Its be

  • well (Score:4, Funny)

    by nomadic (141991) <nomadicworld@NOSpam.gmail.com> on Wednesday December 02, 2009 @01:24PM (#30300024) Homepage
    Why not play Tesla instead?
    • by TimeElf1 (781120)
      They can if you were to reformat it into 8 bit music score. Although the more complex the music the less likely the chance that it will work well.
  • It's all good fun until you get that bill from your electric company... (Yes, I know it is very low current, hence not really that much power.)
    • Re: (Score:2, Informative)

      by Sly-Guy (2100)

      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

      • 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.
        So about the same as an electric shower, maybe a little higher.

        In other words expensive to run continuously but not too bad for occasional use.

  • I was watching this and browsed to some other video : http://www.youtube.com/watch?v=aOZEpP_zzaw&feature=related [youtube.com]

    It looks as though there is a stereo setup there? Or is it more to do with the frequencies or something?

    Also , how do these sound in real life? Does the sound have a point source, or does it just envelope the listener becoming a whole part of the environment? What's the lowest/highest frequency they can produce? How Hifi are they?

    • Re: (Score:3, Informative)

      by Sly-Guy (2100)

      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

  • by Kazoo the Clown (644526) on Wednesday December 02, 2009 @02:06PM (#30300548)
    And I could do without breathing in all that ozone...
    • What do you have against ozone?
      • by WaXHeLL (452463)

        Ozone is really bad for you -- it's an irritant and a powerful oxidizer. Imagine what that does to your lungs. OSHA has pretty tight standards on ozone exposure.

  • If they could get Jack White [google.com] on board this could make for an interesting concert.

  • by MillionthMonkey (240664) on Wednesday December 02, 2009 @02:36PM (#30300926)
    (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.
    • I left out the page I referenced with a schematic. [aaroncake.net] (The page is still there.) Everything to the right of his "C1" capacitor is what I'm describing; the stuff to the left is just for making a DC wall adapter to power it.
    • by slimjim8094 (941042) <slashdot3NO@SPAMjustconnected.net> on Wednesday December 02, 2009 @03:49PM (#30302126)

      I can't speak to the rest of this - though it sounds quite dangerous - but DON'T FUCK AROUND WITH A CRT UNLESS YOU KNOW WHAT YOU ARE DOING

      There's banks of capacitors in there that, if charged up, will kill you in an instant, if you're unlucky or stupid enough to bridge one. They hold about 30kV. If you want to try this, make sure you leave the TV unplugged for a few days, to drain the caps - or properly discharge it. In theory, you can ground the anode - but I'm not qualified to ensure that's safe. I can't speak for the rest of it, but it sounds fairly dangerous as well.

      • Shorting the caps with a screwdriver is sufficient. CRT's are only dangerous if you don't know what a fucking cap does.
      • by chrizlax (1584427)
        Actually, most high voltage power supplies now contain bleeder resistors [wikipedia.org], which are large value (many megaohm) resistors connected in parallel across all high voltage capacitors, slowly discharging them when the power is disconnected at a rate unlikely to affect normal operation, hence discharging them to a safe level within a few hours.

        The rest of it really isn't that dangerous either, as the high voltage output is AC at a high frequency, and hence because of the skin effect [wikipedia.org] only flows over the surface o

  • In addition to thegeekgroup.org and pupman, there is also 4hv.org. If interested, 4hv runs an IRC chatroom on the shadowworld network called #hvcomm
  • Original poster and taggers missed the obligatory Disaster Area reference.

The first rule of intelligent tinkering is to save all the parts. -- Paul Erlich

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