Opto endstop filament sensor prusa I3 MK3

thingiverse

I built my Prusa I3 MK3 clone without a laser filament module, but I did have some common and cheap opto-endstop modules on hand. Using these, I created a sensor to detect when my filament runs out. This sensor struggles with see-through filaments as they appear empty when there's actually filament in place. However, non-see through filaments work just fine. I desoldered the plastic connector from one of the opto endstop modules and mounted it on the other side of the PCB to simplify my cable setup. The module fits perfectly on top of the Prusa MK3 extruder as a replacement for its original lid. To ensure smooth filament flow, I use teflon tubing to create a path for the filament. This allows the opto module to function even when the tubing blocks the sensing beam.