Ender3 Runout Sensor From Harvested Z-axis

Before beginning this model, the following harvested/spare items are needed:

• Qty (2) - Linear bearings & washer
• Qty (1)  - Z-axis microswitch/endstop
• Various small screws
• Spare wire & connectors for creating or lengthening the z-endstop cable and forming the runout sensor cable.  

Print the 3 parts base, cover, and pulley.  Install the bearings and washer spacer on pulley.  The pulley is a copy of the linear guide wheels, but it has a groove for the filament.  Install pulley assembly on base.  Next install the microswitch on the base.  Choose a spot for the filament runout sensor to mount to, then mount.  Test the micro switch, and finally install the cover to secure filament.

For wiring the sensor to work with your printer, search something like, “install a filament sensor on your Ender 3,” in a search engine.  There are many different tutorials with different driver boards along with the firmware/software setup.  I use klipper with a BTT SKR Mini E3 V3 driver board and rPi which makes adding this very easy.

Current setup is designed to be used with a direct drive mod on the Ender-3 with the filament roll top center.  Additional parts might be required for using with a Bowden tube Ender-3.  

Optional Parts:

• Amazon JST-XH & Dupont Connector Kit