For a recent column in the Dutch newspaper de Volkskrant, Rolf Hut built a slick longboard with LED strips that respond to speed. If you think that sounds awesome, wait until you see it in action.
As the Maker explains, four magnets and a Hall effect sensor are used to measure the longboard’s speed so the Adafruit NeoPixels can react at the same pace. To achieve this, the magnets are glued to the inside of each wheel, while a Hall sensor counts the number of revolutions and sends that information over to one of two Arduino Micros. The first Arduino translates that into a speed, while the second Micro converts that speed into a signal for the LEDs. Everything is powered by a power bank.