Ender Pro 3 filament runout sensor

thingiverse

Like most all of us that are into 3D printing I've ended up with a large collection of filament spools with small amounts of filament left on them. I've been trying to find a way to use those short bits of filament, instead of throwing them away. I tried welding filament together, unsuccessfully, and then I discovered filament runout sensors. I found this on All3dp.com: Ender 3 Pro I found this as a starting point: https://all3dp.com/2/ender-3-filament-sensor-runout/ These are easy to add if you are running Octoprint. I use a small microswitch you can buy ten at a time for a couple bucks from Amazon: WINOMO Mini Micro Limit Switch Roller Lever Arm SPDT Snap Action https://www.amazon.com/gp/product/B01HHPD22S/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 You also need the right ball bearings. You must be careful on Amazon, as these are referred to as skateboard bearings. What will trip you up is some of them have an 8 mm center, and others have a 10 mm center. I made the mistake of ordering the 10 mm bearings the second time I ordered bearings and found that they didn’t fit most of the designs that were out there. I fixed that by creating some 10mm to 8mm bearing bushings. Those bushings are included among the files. The correct bearings can be ordered from Amazon here: 608ZZ Metal Double Shielded Miniature Deep Groove Skateboard Ball Bearings (8mm x 22mm x 7mm) https://www.amazon.com/gp/product/B07H83VV6B/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 I found a filament sensor body for the Ender Pro 3 here: Ender 3 Pro Bearing Filament Guide and Runout Sensor by DrJekyllXYZ on Thingiverse: https://www.thingiverse.com/thing:4563996 However, didn’t really like the way it attached to my Ender Pro 3. I’d been using a ball bearing equipped filament roller guide that I got here: Ender 3 Filament Roller Guide by Holspeed on Thingiverse: http://www.thingiverse.com/thing:3052488 This filament roller guide fits the Ender 3 well. It just slides on, is very rigidly attached, but can be removed with a good strong tug. So, I merged the two designs. I also found that the wide channel on this design allowed the filament to sometimes slip to one side and up beside the bearing, making the Octoprint incorrectly think there was no filament. So, I added a filament hole/guide to prevent that.