Hey - has anyone built a filament sensor? I searched, but all I can find is instructions to build one that sets off a buzzer if the spool runs low, or one that verifies the filament diameter and prints it on an LCD.
What I was thinking was a pair of solid aluminum rollers with metal bearings being pulled together with a spring or two. These rollers would be wired (through the bearings) to the arduino board. The board would send current through the circuit and if it detects the switch closing (meaning the filament is out) it automatically pauses the print.
Not sure if this all makes sense?