Part of the POV circuit is a Hall effect switch.The magnet is held on the fork and provides the “zero degree” reference for starting the display.
I’ve not used a hall effect switch before, so thought a quick test circuit was in order. Allegro do a number of Hall effect switches, which I found from a quick glance through the Farnell website. I randomly picked the A1120. Not too expensive; 88p each. The user (i.e. me) supplies power, ground and a pull up resistor to pull the output high. When the device is “on”, the output gets pulled low.
For this test circuit, I’ve added an LED to give a visual indication of the voltage.
Easy to setup, as shown in the photo below. With no magnet nearby:
And with a magnet nearby:
Success! Next step; input into a PIC…