At age 25, competitive skateboarder Justin Bishop lost his vision to the degenerative eye disease retinitis pigmentosa. But seven years later, he’s pulling even more insane stunts, thanks to a new assistive technology that he helped pioneer.

It’s called the Sonic Localizer, a portable sound system that’s the size of a boom box but with eight small speakers positioned in a tight line so that their sound waves overlap and mostly cancel each other out. Instead of just blasting one giant wall of sound, the device uses this “acoustical phased array” to create a tightly focused beam of sound. The beam narrows the further you get from the device, so when Bishop positions it near a ramp or jump, he now has a homing beacon he can follow. Stagger a few around a skate park, and the various rhythmic tones create what he calls a “soundscape” of machine-made echolocation.

Technology company Not Impossible Labs designed the device to be piloted by Bishop as part of an “Absurdity Project” with the shoe and clothing company Zappos. For Zappos, the idea represented a unique way to highlight their brand values and team build at the same time. “The Absurdity Project allowed us to tap the Zappos family to solve an issue of inaccessibility someone in our community was being hindered by, ultimately inspiring others to break the mold and do impossible things,” says Tyler Williams, the company’s director of brand experience in an email to Fast Company.

To do that, Not Impossible Labs initially asked Zappos employees to identify a generally difficult-to-solve problem and person whose life is affected by it. Someone who used to skate with Bishop shared about how he’d been on track to turn pro before going blind. “One of the main governing principles at Not Impossible is called ‘help one, help many,'” says Not Impossible CEO Mick Ebeling. “We take a problem for one person, in this case Justin, and we create a solution that works perfectly and powerfully for him.”

The product development process started in September 2018 and took about seven months of trial and error to complete. At first, the team tinkered with the idea of using GPS technology to relay Bishop updates on his location as he moved around a park. That changed when everyone realized that Bishop already relied on sound to help navigate his environment. He just needed something that he could interpret at high speeds. Having Bishop shape that solution ensures it will likely work well for others. To inspire more people to use these devices, Not Impossible made a short documentary.

Bishop’s definitely proved the idea can work. He recently skated an extreme course at the pro Dew Tour in Long Beach, California, and has made his own “part” or demo reel of gorilla stunts shot in crowded areas around hometown Las Vegas. “When I’m skateboarding, I’ll set it up in certain places where I’m like, ‘Alright, I need to know that when I hear this wall of sound, that I need to ollie or carve to the left,'” he says.

Bishop still follows the same presession ritual as other skaters, walking a course beforehand to get a feel for how he might flow through it. He also skates while holding a white cane with a rounded tip to probe ahead for shifting contours. “Now I can actually focus on tricks and really push my abilities for the future,” he says.