Okay, sorry, thought there is no interest.. okay, but than I wanna hear your opinions to my suggestions:
first of all, I wanna say, this: okay, a 3D printer is really accurate, right ? there a no sensors no nothing. Also on PLASMA CNC CUTTING machines, there are no sensors eather, right ? But what happen du a x,x axis with a range up to 20 meters ? Are they accurate enough with a error margon of +-5mm ?? I guess no, right ?
So, here is my suggestions..
the are Wire-resistors. So, why not wire a 20 meter wire resistor, and measure the current constantly ? Understand ?
Second idea is: let us place every 5mm a resistor, than we have to measure the current. Note: the resistors must be wired in line.
third idea: let us place a yardstick on all tracks, than install a camera, and calculate the numbers.
good ideas ? or do you have better ideas ?