This is the wiring diagram I sent to Doc:
“Idiot level” for people that have never seen an electrical schematic, but more importantly practical.
I think @matthewepler had the 1k Ohm resistor on the wrong wire. Of course it won’t hurt to put a resistor on the GND wire whether you really need it or not. I would tape it as shown to a small block of wood, or a piece of lego, something like that so you can move it around and find the optimal distance from the magnet, and then once you’ve found it you can glue it into place. I don’t think you want to move the magnet, I think that would go on the outside of the rotating gear and you move the hall effect sensor to the sweet spot.