As with many great projects, this one started out with the idea of “why not build something interesting and a little bit crazy?” What hacker Johan Beyers came up with a speedometer that allows observers to see his dog’s speed not via a GPS or IMU, but simply by how the device’s pulsed LEDs line up.
An Arduino provides the timing for each LED, forming a pattern that looks different depending on how fast the pooch is running. Since the dog is traveling fairly slowly, it’s difficult to discern a proper POV effect, how the numbers line up can be seen more clearly using a long-exposure photograph.
It’s an interesting concept to put in the back of your mind for speed indication purposes. You can read more about Beyers’ project here.