Super-Real Mario Kart

Geek Squad: Hunter Smith of Waterloo Labs [second from left] helped four interns transform go-karts into interactive racers fit for a Super Nintendo game.  Jeff Wilson

One summer, a young engineer walked into Austin’s Park, an amusement center outside the Texas capital, and introduced himself to the manager as an intern from Waterloo Labs—a hacking collaborative sponsored by the engineering juggernaut National Instruments. He and his colleagues wanted to convert the go-kart track into a real-life, crash-happy version of the classic videogame series Mario Kart. The manager didn’t just agree. He lent him a kart.

In Super Mario Kart, cartoon drivers zoom around a track littered with interactive objects. Some boost a player’s speed, others hijack steering, and many can be launched at competitors. Four interns at Waterloo Labs grew up playing the game, so when someone suggested making a real-world version, they couldn’t resist. “We weren’t entirely sure how we were going to do it,” says intern Tim Lynch, “but we said, ‘Okay, we need to do this.’ ”

Re-creating the game’s interactivity meant that objects on the track had to communicate with speeding go-karts. At first, the team thought of using passive, close-range radio-frequency identification (RFID) tags. The interns tested that idea by tossing their ID cards at a security scanner to see whether the embedded chips transmitted a signal fast enough. “That didn’t work,” says Humphrey Huang. Next, they tried an active, self-powered RFID system. It cost an extra $500 but could transmit signals as far as 30 feet away, allowing each kart to interact with objects via its own RFID reader.

The interns’ biggest hurdle: overriding the kart’s controls. “We needed to be able to fight against someone trying to turn the wheel,” says Lynch. They eventually selected powerful pneumatic pistons, which they attached to the chassis using zip ties, duct tape, and braces. When a driver captured or collided with an item, a reader would send that item’s unique ID to the computer, which, in turn, ordered pistons, valves, or servomotors to swerve, stop, or speed up the kart [see “How It Works,” next page].