diy linear encoder

hi all, i know it's been a while and rather than resurect a very old thread

i thought i'd start a new one... :) for those who were interested to know what ended up happening

i ended up installing the magnets on the milling machine along with a hall effect sensor (3503u) and i mapped out the 10bit readings vs distance in 0.1mm increments,

aside from the middle which may as well be a flat spot i think it might be doable with two maybe three hall effect sensors, or even better smaller magnets maybe 5mm wide ones instead of 10mm, if nothing else the flat spot would also be usable

however at the moment i don't have a large amount of time to spend reducing it further to use it soley as a linear measurement device,
i'm going to reinstall the old hall effect encoders and use the new "linear encoder" as a way to remove the backlash by detecting when the table starts moving again when the direction is reversed,

for those who are interested in the actaul readings i've attached them as a txt file