Ender 3 Direct Drive Extruder + Filament Runout Sensor + Dust Filter

thingiverse

I added a Dust Filter and a Filament Runout sensor to the direct drive mod. I installed a BLTouch, using the Z Limit Switch as a filament runout sensor. I noticed that the tip of the limit switch had to accept filament in both directions. If a filament runout occurs, the extruder retracts filament back to the limit switch. I modified the stock Ender 3 Limit Switch by adding an LED. I grabbed one from around and soldered it to the limit switch along with its resistor. The screws are nylon M3 with nylon nuts. I bought a bunch of them in various lengths, then cut them down to size as needed. 11/01/2019 - I made some slight modifications to the cover today.