How to Turn Your Skateboard Ramp into a Mobile Soundsystem

If you're going to lug a ratty old amp or boombox to your next parking lot shred session, there's one universally agreed-upon thing to do: blast Slayer. I mean, really blast Slayer. But if you're looking to score your next sesh with something a bit headier, something that plays with the sounds of (sub)urban skateboarding as a medium, you'll want to hack that shitty backyard ramp into a mobile soundsystem.

That's the idea behind SkateHack, an "urban art and research project" at the intersection of skating, hacking, and open-source technologies. By offering a completely open platform—the folks behind the project have released a toolkit for anyone who might like to mess around with the sonic profiles of skating and the city—SkateHack aims to provide skaters with the means to easily build what amount to portable, experimental boomboxes.

All you need are a couple of small contact microphones, a few other off-the-shelf components, some sort of amplifier, and an iOS device. It entails rigging a contact mic or two, together with a piezoelectric disc (a small acoustic sensor that can be built in no more than 10 minutes and for only $5 a pop), to a funbox, as seen above.

The mics and piezo sensor then convert the vibrations that you generate while rolling off (or over) the box into triggers; basically, when you when hit a certain point on the box that's been mic'd up, a signal is generated that your software can then process into almost any pre-programmed sound you'd like. Think of it this way: Your ramp is a drum, and your deck is a drumstick.

As SkateHack's Simon Morris explained over at Make Zine:

The piezo disc connects in the mobile device’s input jack and triggers sounds when hit using MobMuPlat’s open source software platform. Audio signals from the piezo are converted into .wav file triggers. MobMuPlat is an open-source software platform which runs Pure Data on iOS devices. With MobMuPlat you can program which sounds to trigger inside the app with .wav and .aif file extensions.

That might sound a bit complicated, but it's actually pretty easy to pull off, provided you've got the parts on hand and a baseline knowledge of acoustics. Forget Slayer. All tomorrow's demo reels just might be set to a seemingly infinite slate of blips, blorps, and "game-over" style chip tune downscales.

Here's a half-pipe sized SkateHack demo at Sweden's Gagnef Festival in 2012, replete with 16 piezo sensors and four contact mics:

It's all part of a bigger push to sonify the city—and everything else, too. SkateHack's mission, after all, points toward finding "new ways of interacting with city spaces through the integration of technology, sound and live performance," according to the project's website.

But the real end goal strikes an even deeper chord. Skaters and hackers are kindred spirits in the sense that so often the very acts of "skating" or "hacking" run afoul of the law.

"Both skateboarding and hacking involve using information from the surrounding environment, modifying it, and creating new modes of interaction," SkateHack's site explains. As such skateboarders, much like hackers, often face stiff penalties "when it comes to expressing their creativity, skill and talent which in many cases, question traditional ideas about ownership."

"Laws such as PIPA and SOPA threaten to tighten restrictions on piracy while some legislation in some U.S. cities prohibit the use of skateboards on any public road," the site adds. "In many cases, skateboarders are arrested for breaking private property laws much like a hacker who is accused for copyright infringement."

A mutual coping mechanism, then.