[Thor's] hammer, Mjolnir, is pretty freaking awesome. It can only be picked up by [Thor], he can use it to fly, and probably the coolest part, it can summon lightning. After watching the first movie, and goofing around with the guys at ArcAttack, I had this idea that I could stuff a tiny tesla coil into a mjolnir and end up with a really cool prop.
At this point, I had to make a decision. I was either going to go portable and live with small arcs, or make this a stationary piece and hide a giant tesla coil in a base. It would have bigger arcs, but I couldn’t carry it around. While I may re-visit the stationary version at some point, I ultimately decided I wanted to be able to wander around and play with this thing.
I had seen some videos of [Staci Elaan] showing off her battery-powered coils and I really liked her results. I figured, with her experience, she could probably do a better job than I could on getting the most bang out of a small package. She was happy to be involved and delivered a small 12v powered coil for me to work with. I should also point out that the coils [Staci] makes are usually donated to educational groups. This woman is awesome.
She had built this big flat head on it, with the initial plan being that it would be the front “face” of the hammer. It didn’t really work out that way though. I ended up having to increase the size of the head a bit and change the orientation of the coil. I experimented with different types of foam and you can see in the “making of” video what I finally ended up using. The blue insulation board you see in the pictures melted way too easily.
After the hammer was all constructed, and ready to film, we shipped it to California. As you might know, Hackaday is connected to a studio there, now called inside.com. When it arrived, it had suffered a tiny bit of damage and the arcs were a bit smaller. They had gone from roughly 4 inches down to maybe 3. We filmed a few videos and had a ton of fun. Unfortunately, I learned a month later that all the footage for [Thor's] hammer was lost.
I had them ship the hammer back to me in Missouri, and this time it was very damaged when it arrived. I modified the design a little bit, re-assembled it, and tested it out. The arcs were still roughly 3″ when going to another piece of metal and I was finally going to be able to share this project. I cobbled together a quick costume out of a t-shirt, some foam board, and hot glue and now you see the result!
For those who would like to learn more about the coil itself, you can find the circuit and an entire lesson on solid state coils here(pdf 8MB).
Lets jump into some pictures!
[Staci] supplied pictures of the various parts of the coil during construction. Keep in mind, she didn’t have a lot of time and I asked her to get this done pretty quickly.
The Boost converter:
The controller card:
The HV coil:
This was all initially going to fit in the handle, but I gave her the wrong dimensions. It ended up being millimeters too wide. It now resides in the head of the hammer with the coil.
The initial design that was way too melty and didn’t work very well:
The final design, big but functional:
The whole time, I was scared someone else would beat me to the punch. It is such a simple idea. I think a stationary one that could do arcs of several feet would be fun to see as well, but I’ll have to save that for another time.