Remember that time I got to work with the MythBusters on the Discovery Channel?

That was awesome. For those who didn’t catch our episode of Unchained Reaction, we built a warehouse-sized Rube Goldberg machine for the show. The theme was “Movie Mayhem”, so our machine rolls through different silly movie tropes. The red carpet intro, the projectiles, most of the electronic switches, and the wiring and pyrotechnics of the finale are my work.

The finale is my favourite part of the machine. Check it out:



Blam!

The electronics behind it are simple and adorable, to fit with the aesthetic of the show. And being a Rube Goldberg machine, every piece of the machine must automatically cue the next. Here’s how the finale came together…

(PS: These pictures are all behind the scenes shots from while the machine was in progress. From time to time you’ll have to use your imagination a bit as to what it looked like in the “polished-for-TV” phase.)

The last event to happen in the machine before it reaches my finale is Mark and Wendy’s skyscraper flipbook. (They’ve got a thing for flipbooks. Maybe you saw their kickstarter?) The book flips up the building, revealing an animation of a monkey climbing. The last page releases a stuffed monkey onto the top of the building:



The monkey is what starts the finale going. The rising monkey pulls a string that releases a UFO I built out of a BBQ into the sky:



A few things happen as the UFO takes off: First off, there’s a flare stuffed up in its tailpipe. Takeoff slyly lights said flare, making the UFO look like it’s awesomely blasting through space. Wicked. Second off, it’s covered in LEDs. The release of the UFO also pulls a small tab out of a clothes pin with two metal contacts on the inside. With the tab out of the way, the contacts close and the electronics on the UFO are lit, making it look super sweet. And lastly, the bottom of the UFO is rigged to catch some trip wire along it’s path across the building. When the wire is tripped, small projectile fireworks shoot from the UFO to the tiny city below:



Before: Not exploded city. After: Totally exploded city. (Wendy, our resident artist, designed both cities.)

If you’re curious, the tripwire on the UFO also ignited a little pyrotechnic magic down below, which melted the plastic line holding up the “not exploded” city, hence revealing the exploded one. The non-exploded city, upon falling, also pulls the trigger on the next link in the machine: A little rope, around a little pully:



And a little pin, supporting a little steel ball.



With the pin removed, the ball begins to roll down a little ramp. This ramp, however, is spotted with little open circuits:



The little open circuits just squares of tinfoil bolted into 2x4s. (Simple solutions are often best, especially when you’re trying to be cute for TV.) It’s difficult to see in the photo, but the tinfoil squares on each side do not touch in the middle of the ramp. Each square is wired to little pyrotechnic devices hidden in mortars in the “field”. (We’re going for the “attacking aliens” movie trope here, if you couldn’t tell.) As the ball rolls down the ramp, it passes momentarily through each tinfoil switch. The steel ball completes the circuit between the two foil contacts, and fires off the explosions in the mortars. The final foil switch fires the enormous propane popper at the very end.

Here you can see Wendy making the field look awesome, and the switching mechanism in the middle:



And when it gets to the end, (let’s watch it again!):



Blam!

Working on this project was one of the most entertaining jobs I’ve had thus far. I found the show itself to be a bit lackluster to be honest (drama pulls more views than engineering), but the making of was the silliest and most enjoyable bit of engineering I’ve done yet.

If you’d like to see more photos, you can check ’em out on my G+ page!