Arrgh
I just had an idea for how to align it correctly each time, but it's too complicated for me to explain.
I'll try anyway.
It would involve engaging and disengaging a gear that was attached to a beam that was limited to a certain amount of rotation that corresponded to the amount of rotation necessary to make a 90 degree turn on the larger gear, and was spring-loaded to move back to its original position every time it disengaged.
I get what you're saying, kind of like a mechanical way of having the black turntable mesh with a gear, winding up a spring and causing more and more resistance until it stopped at exactly 90 degrees (?)
I'm thinking that there has to be a more simpler way with editing the code. Right now, I have it so it moves exactly 90 degrees with no counter or anything to check if it's accurate. Instead, I could have it move at "unlimited" until it reached the 90 degree mark and stop, would that be more accurate?