Dancing Fire "Pyro Board"

I got inspired to do this project after watching some youtube videos. It's basically a 2 dimensional Ruben's Tube. Propane is pumped into a chamber with speakers in it and sound pressure from music opens or closes thousands of little holes. The result is a 2d array of tiny fires that dance to music.

Fysikshow's pyro board on youtube

My pyro board

The hardest part of the project was making the plate that goes on top. It needed to have holes at <0.075" in diameter spaced at least 0.25" apart for the pyro board to work; with large holes, there would be way too much propane leaking out and the project would basically be a metal bonfire. 

After a few hours of searching and talking to a mechanical engineer who mentored my robotics team, I determined that there was no good off the shelf solution. All the plates with holes I found online had massive holes that covered a good portion of the surface area. 

Off the shelf solution with holes that are too large

999 tiny holes all drilled by hand

The only other option was to drill all the holes by hand, which is what I did. I used two old cookie trays to make the chamber and bought some cheap used speakers at the recycle center. In the end I drilled 999 (27x37) 1/16" holes and broke 6 drill bits.

I put the speakers much lower than the cookie trays to make sure they didn't get hot and catch fire. To get the propane in, I used a hose clamped line per the recommendation of a Home Depot employee; all the standard fittings had pressure regulators that made the pyro board unusable. I've included a few pictures and gifs, but I'd highly recommend checking out the video with sound. 

Future improvements include making a larger board with smaller holes and using math and science to figure out where to position the speakers for the best sounds interference. I suspect positioning the speakers on the side of the chamber rather than the bottom would be ideal. The drilling process was pretty tedious so I'll probably use a CNC router next time. I also found that the board was pretty sensitive to wind, but it's definitely not safe enough to run indoors.