Bikes Craft & Design Technology
The Transformation of a Bike Radar Device


Call it market research. Franz Struwig met a man riding his bike on the wrong side of the street because he was too worried about cars overtaking and striking him from behind. Struwig, who is the founder and managing director of iKubu, a radar device startup in Stellenbosch, South Africa, decided there was a product need his team could fill.

It became Backtracker, a hackable rear-view radar for bikes that’s got an open API and is currently crowdfunding. But that’s the end of the story; what concerns us is the middle.

“We generally try to find interesting problems that we can solve,” says Struwig. “We help people to see what they can’t.” And that’s what’s behind you. So iKubu started building a device to recognize cars approaching from behind and alert bicyclists.


They built a rack to support it, and placed a 10 GHz radar antenna on it. It was wired to a single LED on the handlebars that blinked faster as cars got closer. And it was all hacked together from components from previous projects or off-the-shelf components. It was clunky, heavy, and big, says Struwig. Not something you’d want on your bike.


So iKubu built another prototype, sleek and small and shiny, to pitch to manufacturers in the bike industry. Though there was some venture capital interest, it never made it to market. The lesson, says Struwig: “Nobody will ever put in the same amount of passion and effort into taking your product to market than you, yourself.”

The latest version features a 24 GHz radar antenna — high enough to resolve more targets and small enough to fit on a bike — an ARM processor, and Bluetooth LE to communicate with the front unit.

The radar creates a doppler map, and recognizes not only the vehicle, but how far away it is and how quicky it’s approaching. It communicates this to the cyclist by a system of LEDs, and to the car by increasing the rate at which the tail light blinks as the car gets closer.


“This is not about warning the cyclist,” says Struwig. “We don’t know if a car’s going to hit you or not. This is just about providing extra information. The cyclist understands the context of where he’s at.”

Importantly, iKubu is offering both the open API and development support and schematics. “We want to make it easy for people to hack it,” says Struwig, adding that this applies to companies that sell bicycle computers, for example, as well as makers who want to build a smartphone app or alternative ways to display the data. “Innovators out there have a way of coming up with awesome ways of doing things, if you just give them access.”

More info on Backtracker is available at iKubu’s Dragon Innovation page.



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Nathan Hurst is an editor at Make. He loves anything having to do with science or bicycling. He tweets as @nathanbhurst.

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