I took a break from looking at hardware for about. 6 hours, got back to it and solved the problem 0-0. this is why it’s good to take breaks lol. Retested it on an arduino nano and it did refuse to go to zero. Not sure what was up with that, the code was fine though. That board has also been through a bit. Got to working on the design for the boxes to hold the mirrors and diffraction grating.