It’s The Detonator! What is The Detonator you ask? Well, for Maker Faire Milwaukee we build a fire poofer, which is a device that shoots flames into the air. Workmate John McGeen started the poofer build and we finished it up at Milwaukee Makerpace. Along the way we experimented with a torch, candles, and grill igniters, until Dan the Blacksmith finally added a pilot line and some steel wool.
The Detonator went through a few revisions, but I’ll walk through the construction of it for this blog post. We brainstormed a few different ideas to trigger the poofer, but in the end I went with something simple than I knew would work reliably for the entire weekend. (And it did!)
I started by using MakerCase to design a box I could laser cut. I used 3mm black acrylic because I have a lot of it, and I made the box the size that worked with the acrylic I had. The image shows the acrylic (gray parts) and one piece of 1/4″ wood (which is tan in the image.) The wood piece went on the inside, right under the top acrylic with the hole for the button.
Since I wanted The Detonator to withstand being pressed, slammed, and pounded on by hundreds of people over the course of two days, I also built a wooden box that fit inside the acrylic box. This added strength and weight to it.
I didn’t just want a plain black box, so I added some bright yellow vinyl to it. I cut the vinyl with a Silhouette Cameo. The image above shows how I determined wrapping the vinyl around the edges.
Here are the vinyl pieces I cut. I added cut outlines around the pieces so I’d be able to line it up correctly. It worked pretty well. (I didn’t take time to measure or mark things, but that would be a recommendation.)
Above is my final “pretty” illustration of The Detonator. Below is a very black photo of The Detonator. I’m fairly pleased with how it turned out, especially since it was a rush job to build it.
There are four connector posts, but only two got used in the end. I originally had just the two in the center, but ended up splitting them and adding extra posts so I could split power between 12 volts (well, 18 volts, sort of) for the solenoid, and 4.5 volts for the grill igniters. We ended up ditching the grill igniters, so in the end I only needed one pair of connectors. Oh well!
Here’s the inside! There’s a Pololu A-Star 32U4 Micro mounted on an Adafruit Perma-Proto Half-sized Breadboard PCB with some screw terminal connectors, which is connected to a relay board. The board I used had four relays, but since we didn’t use the grill igniters I could have used a two relay board. (Also, relay boards are super-cheap on ebay.) There’s also a relay controlling a beeper that beeps a countdown. (See the video below.)
Overall The Detonator was a quick build. and there’s a few things that could have been a bit more polished. For instance, I cracked the acrylic a bit when I drilled more holes for the connection posts. In an ideal world I would have laser cut a new piece, but I didn’t have time. I also could have made the code a bit simpler after removal of the batteries for the grill igniters, but hey… The Detonator turned out good for a quick fire poofer controller!