GPS Bike Speedometer Marks Velocity in Red, Green and Blue

If you want to add a speedometer to your bike, generally this means running wires from your fork to handlebars, installing a magnet on a spoke, and calibrating everything based on wheel diameter. While not that big of a deal, it would be much easier if you could simply place the speedometer on your handlebars and be done with it. For that matter, if you need to know your speed in a quick glance, digits aren’t the best indication method.

As an attempt to solve both of these minor issues, I created the GPS RGB Light Speedometer. Inside its 3D-printed housing is a rechargeable battery, a small GPS unit, an Arduino Pro Mini, and of course, an RGB LED. The Pro Mini converts GPS signals into speed using the TinyGPS++ library, which is then translated into corresponding colors on the LED light. This light shines through a top layer of “clear” PLA with green indicating a top speed of over 13 MPH.

While it’s a good method to give you an estimate of how fast you’re going, the device could be expanded to be more “analog” in the colors it displays. One could also add extra GPS functionality, like an indication of how far away from home you’ve wandered.

More info on the project is available on Hackster, and code along with STL files are on GitHub if you’d like to make your own!

Taking this project even further, I could imagine this or a helmet-mounted version being used as a “go/no-go” gauge for more extreme applications. A green light could mean yes, your speed is high enough to jump that gap or red could mean, abort immediately!