How does one put an endstop on an extruder to detect the presence of and home/set the location of filament in the extruder? I have 5 Bowden extruders in one machine that manifold into 1 optical endstop switch for the purpose of loading different materials into a single extruder.
Ive got the optical switch working but want to be able to load filament in and home each extruder and then retract to a know distance to stage each filament to be sent to the extruder at a known distance into a serving system.
I'm really stuck here and need to get this working. Currently I have to manually load the filaments in and then cut them off at a known distance. There has to be a better way!

Using Duet 6hc board with the 3hc expansion board & Simplify3d?
Optical switch TCST2103
I've got CAD drawings and diagrams. I just don't know how to code the filament loading process to get the filaments staged at the right distances from the extruder.
Please help!!