LED POV project, with a spin

These bloody acronyms are a pain. There are 20 different definitions. How about you warn us of which one you refer to at least once in each post then use the initials by all means

So this switches on LED's in a set pattern once per revolution and that makes it visible as a still image --right?
How do you pickup and time each revolution
How does the arduino know when to switch on and how do you convey that instruction to the arduino?
How do you get power to the LED's

I would imagine a world full of rotating wheels each with the advertisers message flashing out . That would be another bloody pain. but I think you have let the cat out of the bag.