Filament runout sensor - hotend tube fitting edition (one piece of tubing, not two)

thingiverse

Note: Please don't mind the gruff looking lid, I had some over-extrusion and never re-printed because the lid worked fine. I looked at other filament runout sensors out there, and I had issues with all of the current designs I could find. While many of them are really well made, none of them met my expectations. What I have here is a filament runout sensor designed to fit an M10(1.0 thread) tube fitting for Bowden tubes, just like the one used on many hotends. This is because I didn't want the tube to slide back and forth during retractions, and the fitting will hold it steady. Furthermore, I wanted a filament sensor that needed only a single piece of tubing with minimal modification instead of two pieces placed into the housing. So I spent several prints getting the distance just right so the switch is triggered by filament running into a tube that's been cut open and releases once the filament leaves. Optionally, you can even mount this to your extruder frame just by drilling out the filament feeding hole and adding a way to seat a tube in there with no movement during retractions. For me, I used a different tube fitting and drilled it out to fit a tube very snugly so the tube needs to be gripped tightly to move. This then allows me to feed my filament directly into my extruder frame via tube so it meets only resistance from the movement mechanism. Parts needed: - A piece of Bowden tube (regular and Capricorn should both work) - A knife or other way to slice open a piece of your tube - A microswitch like this one: https://www.ebay.com/itm/10pcs-Micro-Roller-Lever-Arm-Open-Close-Limit-Switch-Kw12-3-PCB-Microswitch-Hot/123803444289?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 Keep in mind, this housing is designed for that specific switch. I cannot guarantee that any other shape of switch will work. - Some basic soldering stuff to attach the wires to the sensor like any other sensor out there A M10 Bowden fitting with a 1.0mm thread pitch (this is the one the MK8 hotend on the Ender 3 uses for instance, it is an extremely common fitting, you probably have one)