Tesla Coil Hat V1.0

This might be the best effort/reward thing I’ve ever built.

(video from MrMagicBean on YouTube)

In 2020 I wanted a costume for Shambino (mini version of Shambala festival). I’d seen various iterations of the “Plasma globe” as part of a costume, notably Henge, and thought a Tesla coil would be much cooler. But I was short of time having spent many hours working on the kids costumes. My first thought was one of the little battery powered Tesla coil kits that litter eBay. These aren’t strictly Tesla coils – they are “slayer exciter” circuits that boost the battery voltage up to a few kV. They’re fun and they make a good noise but, on a good day, they make 1cm sparks. Rubbish.

Next port of call was the idea of modifying one of the desktop toy, PCB coil, 10cm spark Tesla coils available from various Chinese vendors. I got one and it was ace…for about 5 minutes before it released the magic smoke. The DC power supply that came with it was also rubbish to the point of being dangerous. So I ripped the coil apart and quickly discovered that the components inside were very borderline rated for the voltages involved. So I upgraded the (exploded) power transistors with some that were much higher spec. Worked great from my bench power supply producing beautiful arcs.

Now I needed to make it portable. I decided on 18V Makita drill batteries as power. I have a bunch, they can take lots of abuse and they have enough power to run the coil continually for a long time. I needed to go from this 18V to 50+ V for the input stage. Again I started with a cheap Chinese boost converter. Not even sure what bit of equipment I scavenged it from but it can do 10-24V in, boosting to ~60V max. In theory. I ended up swapping a bunch of parts again to bring it actually into spec.

By this point I was basically out of time, with the festival in a days time and lots of other stuff to do. I packaged the coil in a terrible quality novelty costume top hat, chucked the battery and boost converter loose into a bum bag. Put a push button switch on a cable controlling the 18V in to the boost converter. I expected the whole thing to last five minutes and be somewhat underwhelming.

I wore it for a couple of evenings wanderings at Shambino and it was absolutely amazing. I was triggering it for a few seconds at a time and you could see people look around puzzled to see what the crazy noise was, then they’d come running when they actually saw the sparks. I gathered crowds! People loved putting their hands, tongues and other body parts close enough to pull arcs from it.

It survived Shambino fine, then I wore it every night at Shambala a year later. No modifications other than improving the power connections to the boost converter and a bit of hot glue on the PCB to make everything slightly more robust.

Next year I want a much, much more powerful one…