Opto endstop filament sensor prusa I3 MK3

thingiverse

I did not have any laser filament module avalible when I built my prusa I3 MK3 clone. I did however have a few common and cheap opto-endstop modules laying around so I decided to make use of these to be able to detect when I run out of filament. Note that this sensor is struggling with see-trough filaments as they appear as if there is no filament inserted. But as long as non-see trough filaments are used, it works fine. I decided to desolder the plastic connector of the opto endstop module and mount it on the other side of the PCB to simplify the cable arrangement. It fits right on top of the prusa MK3 extruder as a replacement for the original lid. Use teflon tubing to make the path for the filament as smooth as possible. The opto module will work even with the tubing in the way of the sensing beam.