Step 5: Modify the basis motor circuit
Old floppy disc drives spin the storage medium with 300 turns per minute. This is too slow to build a POV. The repeat rate is only 5 turns per second and the display will flicker. The motor needs to be tuned a little bit to turn faster. An other reason for faster turning is that using the original speed we get only about 2,5V for the circuit. To drive a small micro processor we need a minimum of 3V, 8V would be fine to get regulated 5V.
To make the motor turn faster remove the capacitor that is responsible for the frequency and put a smaller in. I changed the 22nF to a 10nF. To have a greater band of speed adjustment I removed the 22k Ohm variable resistor and put in a 50k Ohm instead.