Singing Tesla Coils

The video above is ArcAttack! playing the classic “Popcorn” through their signature Tesla coils. Solid state Tesla coils (SSTC) can generate sound using what [Ed Ward] calls pulse repetition frequency (PRF) modulation. The heat generated by the plasma flame causes rapid expansion of the surrounding air and a resulting soundwave. An SSTC can be operated at just about any frequency, so you just need to build a controller to handle it. The task is made more difficult because very few electronics are stable in such an intense EM field. [Ed] constructed a small Faraday cage for his microcontroller and used optical interconnects to deliver the signals to the Tesla coils.

[via Laughing Squid]

13 thoughts on “Singing Tesla Coils

  1. OMG!!!!!! the best hackaday post of over 100 this week(what happened to 7 a week?).

    please for the love of god just a few words about it and the link for us to read the details. were not babies. we dont need to have the write up interpreted for us.

    ONE blog per day with whatever has been found for that day. if u miss the deadline them just add it to tomorrows blog. its not like theres a low supply of hacks atm.

  2. This was at a regional Burning Man event called Flipside. Very cool to watch and listen to. Really impressive control schemes on the musical components. Ididnt get a chance to look at it during the day all the gear was put away. Was talking to the guy who thought it up. 3 Octaves worth of notes so far. They were experiment with jacobs ladders and other devices for different tunes. Absolutely brilliant

  3. Quick question: I always only see coils playing single notes songs. Is there a real limitation that prevents playing full wave sound, or would it require that it’s at least converted to a PMS signal first ?

  4. we had a very similar event this past year at our engineering open house (university of illinois).

    it was spectacular. they even played the quintessential super mario brothers theme song.


  5. These coils are DRSSTCs – double-resonant solid-state Tesla coils. They are powered with IGBTs, which limits the frequency to less than 20 kHz at best.

    The reason for this is because they pass so much current – he wants those sparks as big as possible. These were 5 ft last I heard and they’re not even turned up all the way because they’re afraid to blow them before show season is up!

    MOSFETs switch at a higher frequency but also have a much higher resistance. You can build a full-wave coil but your power is limited by what the MOSFETs can handle. If it is analog modulated there is A LOT of heat dropped, so even though the IGBT may be able to modulate at audio it should only be switched for heat concerns. If MOSFETs are pulse-width modulated like a class D amplifier it’s not so bad but still nowhere close to 5 ft without massive MOSFET bricks.

    The two links at the top of Steve Ward’s site (the fella from Illinois) give a lot of info about the hows and whys with schematics.

    They can be pitch-bent, like here:

  6. you can get tesla coils that pretty much replace a speaker and have very good fidelity but the spark is about 1 – 2 inches and they don’t really “match” the sound. look up Audio SSTCs from eastern voltage research.

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