Low-End Parts Make Tesla Coil with a High-End Look

We all know the saying: cheap, fast, or good — pick any two. That rule seems to apply across the spectrum of hackerdom, from software projects to hardware builds. But this DIY Tesla coil build might just manage to deliver on all three.

Cheap? [Jay Bowles]’ Tesla coil is based on a handheld bug zapper that you can find for a couple of bucks, or borrow from the top of the fridge in the relatively bug-free winter months. The spark gap is just a couple of screws set into scraps of nylon cutting board — nothing fancy there. Fast? Almost everything needed to build this is stuff lying around the house, and depending on the state of your junk bin you may not even have to order the polypropylene caps [Jay] recommends. Good? That’s a relative term, of course, and if you define it as a coil capable of putting out pumpkin-slaying lightning bolts or playing “Yakkity Sax”, you’ll likely be disappointed. But there’s no denying that this Tesla coil looks good, from its Lexan base to the door-pull top load. And running off a couple of AA batteries, it’s safe to use too.

[Jay] put a lot of care into winding and dressing the secondary coil neatly, and the whole thing would look great as a desktop toy. Not into the winding part? You can always etch a PCB Tesla coil instead.

21 thoughts on “Low-End Parts Make Tesla Coil with a High-End Look

    1. They make okay adjustable static spark gaps and static terminals fot moving spark gaps.
      Best mini rotor for a rotary spark gap I found was the top of an old brass tap. Essentially four evenly sized brass balls on a nicely balanced hub with a premade threaded axle.

    1. Well it’s not the batteries that are the “protection” against dying, it’s the crappy power supply from the fly swatter. Or perhaps crappy is not the correct name. At frist we may assume that the fly swatter was designed to be non-lethal, otherwise it would not be (allowed) to be sold… (but you should never put your thrust on that statement). So we may assume that the power that is generated by the swatter is safe, therefore the power out of the tesla coil is even safer as it has an efficiency of less then 100% (therefore it could not be more then the swatter generates).
      HOWEVER… if there is a way to accumulate the energy, store it in a capacitor, perhaps a leiden jar of some kind, then if you wait long enough you can accumulate enough energy to kill you. Although I think from the setup in the video that that will not be very likely.

      So to make a long story short… do not underestimate those little batteries. Always think for yourself, if you are the one that’s touching something that’s live… make your own judgment BEFORE you touch it. It doesn’t help you anymore when they say “sorry, I guess I was wrong” because you are dead.

      Regarding the execution of the project. It is a very nice build considering the resources. The door/drawer-knop is a very nice touch.

      1. I’ve seen them make some nice burns on a kid’s face. (Not my kid)
        It all depends on how conductive your skin is.
        A calloused finger is less conducive than a cheek or a lip.
        Flies find them mostly lethal.

    2. If it were possible to store the total electrical energy output from an AA batteries lifespan, then delever it in a fraction of a second, with little to no loss. That’s a lot of energy.
      Accounting for skin effect at the operating frequency and the fact most of that energy is voltage not current. Tingle maybe. Kill doubtful.

    1. From customs: You can only bring in mozzie zappers that have a protective grid and a battery capacity of 6 volts or less. Mozzie zappers without a grid and a higher battery capacity than 6 volts are not allowed.

      Then I searched and found ebay.au sells mozzie zappers and Rays, a local outdoor store sells locally.

      Customs will may ask the following question on importation: ARE THESE GOODS HAND HELD INSECT ELECTROCUTORS (COMMONLY KNOWN AS MOSQUITO BATS, MOSQUITO ZAPPERS, ELECTRIC FLY SWATTERS OR THE LIKE) POWERED BY A STORAGE BATTERY CAPACITY EXCEEDING 6 VOLTS OR THE ELECTRIFIED GRID IS NOT SHIELDED BY A PROTECTIVE GRID LAYER?

      The answer needs to be NO, so when purchasing make sure you don’t exceed 6 volts and the electrified grid IS shielded by a protective grid layer. Typically that is a three layer sandwich with only the middle layer being electrified.

  1. I have a pile of vintage electro therapy devices some are in essence hand held tesla coils. I often do shows with the gear and allow people to try out some of the various devices that operate from 1.5V to 4V.
    It takes around 60ma to interrupt the signal to the heart and if the person is wearing a pace maker I just refuse to demonstrate on them so as to err on the side of caution.

    You can cause pulmonary distress with around 40ma.

    It really depends on the health of the person, how conductive their body is and even the frequency of the shock as to if you are going to cause issues at low power.

    1. A true Tesla coil is an Radio Frequency device. It is high voltage, and there is current, but it travels on the surface of any conductor, including skin. Look up “skin effect” for which there is a formula based on frequency. How much goes through the core of a person in a way that can cause harm… A lot of the danger of a Tesla coil spark is heating to the skin at the point of attachment. Wearing metal thimbles helps, as long as you can ensure the spark will always jump to the thimble.

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