With the enclosure completed, it was time to wire the bitch up.
It’s been a good 8 years since I’ve really designed a circuit, and despite this one being fairly simplistic, there’s a lot I’ve forgotten since high school. Especially when it comes to dealing with resistance and current.
Our schematic called for 3 9-volt batteries in parallel. 3 was mainly an arbitrary number that we figured would be sufficient. I couldn’t find any reliable information on how much current a 9v battery has, or how much the model rocket igniter required in order to actually ignite. Using my father’s multimeter, I tested to see the current for one battery. I blew the fuse, not remembering that I should try the highest setting and work down. I went out and bought more fuses. I set the meter to the highest setting, blew another fuse, cursed at the meter for a few minutes, and decided to just skip having the button stay illuminated when armed.
Wiring all of the buttons was a bitch, and looks absolutely atrocious. The wire we were using was too thick for connecting the buttons in parallel, so I had to “pre-wire” everything by wrapping one wire around the other, soldering it, and leaving a little tip out to solder into the button. Ugh, it looks terrible, but it did the trick. I managed to give myself perhaps the most minor burn possible with a soldering iron (minor injury #2). It didn’t bubble up, flake, smell awful or anything. It barely even hurt, and I forget where it even was.
To test, we taped an igniter to a piece of extra fuse we bought, the thickness of the fuse on the real fireworks, and taped that fuse to the fuse for some stupid little firework that came free with our huge purchase. As it turns out, the illuminated button sucks up most of the current and doesn’t send enough through the igniter. Not even with 3 batteries connected. I disconnected that and the rocker switch, and left just the key switch. With two batteries, the igniter lit up perfectly when we pushed the button now, only it didn’t light the fuse. I cleverly decided to split the tip of the fuse with a knife, shove the igniter in and tape it all together.
Huzzah! Lit fuse! Our shitty little test firework lit up in a fantastically mediocre display of rotten egg smelling smoke and a few sparks. Two of the switches were completely disconnected, but who cares? They were essentially just for show anyways.
We packed everything up, rolled up the 6 lengths of wire and told practically everyone we knew about our fancy little device while waiting for the fourth.
When we showed up to Bill’s on the fourth, the three of us started prepping all of the fuses. Splitting them, shoving an igniter in and taping them together. That way we’re able to just run 6 fireworks out and reattach the alligator clips. If I get copies of the incriminating photos of our prep work, I’ll be sure to post them.
When the time rolled around to actually start setting off fireworks, it was lightly raining. The ability to set everything up quickly, run back and launch them in series came in super handy. Yelling “Fire One! Okay, now Two!”, etc. and watching the fuse light up is really damned fun. There were 3 batches of 6 fireworks, totaling up to nearly 1000$USD of stuff to explode. The first two alternating between a multi-shot box and a single-shot tube. The last one consisting of 4 tubes and ending with two boxes. I don’t think it took any more than a minute between batches.
All in all, almost everything went off perfectly. One box in the second batch failed to go off when the wet fuse fizzled out, which we lit that manually, and then there was a box and a tube in the finale batch were too wet to even light manually.
As for minor injury #3? After all of the real fireworks, and after cleaning up the big stuff, we still had a box full of the free crap to use up. Justin didn’t notice the fuse on one of them pointing at his hand, and when it lit up the sparks burnt his finger. One injury per person, and none of them all too severe. That’s pretty much up to par.