Step 5: Modify the basis motor circuit
The floppy disc drives I used need two different voltages to work. The drives need 12V and 5V. Luckily the voltages on the pcb are connected in a way that makes it possible to place a voltage regulator on it and get the 5V out of the 12V. Just solder the regulator to the holes. There is a motor enable pin that need to be shortened to ground to make the motor turn, do so.
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.