Filament runout sensors on dual extrusion just wire them in series? So if either trips it triggers? Obviously NC and parallel if NO
Depends on what you want the failure mode to be. If you want it to just stop the print entirely, series should work fine. If you want want to just shut down the one extruder the programming would be more complex but you should be able to have it finish the print with only a single nozzle.
@Joe_Morrison that would require a firmware to switch all extruder tool changes to be still handled on one extruder no? Sounds complex (but fun). I would do series if you just want it to stop printing.
Don’t see why you’d want to have one stop and another keep going. Apart from if you did something like a filament changer to continue a print when one roll runs out but that’s probably a fair bit to programming.
Spot on here with the concept. I was working on a similar dual filament runout trigger on my printers awhile ago. I have an X max limit switch port on each extruder that are wired in parallel to the main board. Using NO switches I reassigned the corresponding pin on the main board for the printer to pause and home XY when energized so I can load new filament and then un-pause/resume to continue printing.
It was placed on hold to develop a sensor system that can detect filament runout and jams as well as determine filament diameter if desired. 