Turn a PC Fan into a Scorekeeping POV Display

In preparation for the 2018 Eurobot robotics competition, this hacker needed a way to display his robot’s point total. While a static display like a chalkboard or even a piece of paper could be used, this seems a little simple for a robotics competition. He decided to not just implement LED-based scorekeeping, but made the system spin, using persistence of vision (POV) to show numerical values on a stack of WS2811 RGB LEDs.

Spinning for this project is accomplished via a PC fan, and all electronics including the LEDs, an Arduino Pro Mini, and a battery pack rotate together to avoid any wiring issues. Fan speed is sensed by a Hall effect sensor that picks up a magnet mounted to a corner of the fan.

Numbers to be displayed are transmitted from a computer using an Arduino Nano, along with a pair of nRF24L01 RF transceivers to send data wirelessly. The results can be seen in the video below, and while it’s a little difficult to make out the numbers, one would have to think that they would be easier to distinguish in person.

We wish him and his robot all the best in the upcoming competition, but win or lose the score will certainly be displayed in style!