The Transformation of a Bike Radar Device

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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10 thoughts on “The Transformation of a Bike Radar Device

  1. Charles Duffy says:

    Back when I took the League of American Bicyclists’ TS101 class (Traffic Safety 101), the first day of classroom training went deep into real-world accident statistics. Short form? Once you take out cyclists who are riding at night without lights, being struck from behind is almost unheard of. Being swiped by a vehicle that’s overtaking too close is more common, but that’s avoided by taking the full lane when there isn’t room for another vehicle to safely pass within it (and thus requiring a passing vehicle to change lanes, or allowing you an opportunity to move to the side of the road when judging it safe to do so).

    And if it _is_ a thing you’re still worried about, you can get a big helmet-mounted mirror; a simple, low-tech approach that does the job well.

    1. Bicycle_365 says:

      Agreed, hit from behind is almost unheard of during daylight hours or when properly lit. Taking the lane when required for safety is the best practice. The truth of it is “They may hate you, but they won’t hit you” . This product is in fact providing data to the rider but of how much use is questionable.
      The explosive proliferation of in car “telematics” heads down touch screens and systems that promise to “brake for you” so you can be negligent worry me far more. We need to start collecting data for the class action lawsuits that are in inevitability coming against the manufacturers for producing products dangerous to vulnerable LEGAL road users i.e. bikes and pedestrians.

  2. sofenza says:

    Back when I took the Group of United states Bicyclists’ TS101 category (Traffic Protection 101), the first day of category space training went strong into real-world incident research. Brief form? Once you take out bikers who are driving in the evening without lighting, being hit from behind is almost unprecedented. Being sharpened by a automobile that’s ruling too near is more typical, but that’s prevented by taking the complete street when there isn’t space for another automobile to securely successfully pass within it (and thus demanding a moving automobile to modify paths, or enabling you an probability to shift to the part of the street when evaluating it secure to do so).

    Spybubble Free

  3. j03 says:

    FWIW I’ve had five car vs bicycle encounters and, in agreement with the previous observer’s statement, only one event was a side-swipe–the rest were from the front. However, it’s very important for me to know what’s behind in case I need to pull further out into a lane and to find out I generally glance underneath my arm to view the road (upside down). This gadget could be helpful and it would be interesting to see if it surpassed a mirror in practice.

  4. Franz Struwig says:

    Very interesting comments. Lets look at the facts.

    According to the league of american cyclists, 40 percent of U.S. bicycle deaths are from a driver hitting you from behind! Don’t take my word for it:

    1. Charles Duffy says:

      Your numbers don’t contradict mine.

      First, you aren’t excluding the inadequately-lit case here (which is one of the three biggest risk factors for accident rate [not death rate, they’re different!], next to riding on the sidewalk and riding on the wrong side of the road). Second, I was looking at percentage of accidents; you’re looking at percentage of deaths.

  5. aRkadeFR says:

    playing with some doppler sensor, i’ve never thought about that. Great idea ! Hope to see and try it soon :)

  6. Alex says:

    Oh wow, bike radar devices??!? Never heard of those.. Gonna see if i get one for the Powerbank tour.

  7. Benbrook Bicycle says:

    yes but rear end accidents are a small percentage of the total number of accidents.

    And does it need line of sight? usually there are riders behind you.

  8. hq says:

    Wow! Call me crazy, but this looks EXACTLY like Garmin’s new Varia™ Rearview Radar.

    What are the odds??!

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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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