Not a big deal really... just took an Arduino UNO with a TIP-120 Darlington transistor and a high power white LED.
I read an A/D port and use the 0-1023 reading (times 10) as a parameter for _delay_us() (adjustable strobe rate) and pulse the LED for 10 microseconds each time.
The pulse going into the LED is over 3 amperes!
By adjusting the pot, I can change the strobe rate and "freeze" the fan blades. Notice that the blade appear to be partially transparent. This is because the room lights were on and the CPU heatsink was illuminated by the room light and therefore appeared in the video "behind" the fan blades.