filament runut sensor for Prusa mk2s printer

thingiverse

This is a very simple filament runout sensor to be added to your Prusa mk2s. https://www.youtube.com/watch?v=Ss9GOlhPqW8 I have choosen, for reliability reasons to use an endstop switch instead of an optical sensor. They are very cheap, easy to find on aliexpress https://s.click.aliexpress.com/e/_9AZ9pU I use the Normally Open switch so that the contact is closed when the filament is inserted. Prusa firmware is easily modified to activate the filament runOut option. It does trigger the G600 Gcode command as soon as the filament is cut. It is the regular command to change filament. The sensor snaps on the extruder without any screw. Even the lid is inserted and fixed using a filament "rivet" (see picture). The sensor is designed to fit this exact type of switch... The two wires of the switch go to the Y_Max connector on the mini Rambo board. They are connected to the S and - pins of the connector. There is no polarity you can swap the two pins ! Optionnaly you can add to the calibration menu section "Show End Stops" the display of the filament status. (0 = filament inserted)