POV wheel


I needed something cool to encourage people to join my Circuitry Club in high school, so I built a persistence-of-vision display on a bicycle wheel.

The wheel has 90 sectors and 28 radial pixels for a total of 2520 effective pixels. Images are first resampled from standard rectangular formats to a custom radial format where each pixel is specified by its angle and radius, then loaded into the PROGMEM on an AVR microcontroller. The microcontroller simply measures rotation speed with a magnet and uses pulse-width modulation to apply 8-bit RGB color to each LED.

Get the code here.

The result:

The image appears continuous in real life, but the frame rate of the video camera interferes with that.

Yes, Pikachu's missing part of his face. I only had two days to build the thing. Cut me some slack.

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