Improved Filament motion sensor for Ender 3 V2. Not only detects a filament runout, it also detects a nozzle clog and pauses the print safely. Intended for use with klipper.

Used Parts

M3 20mm Thumbscrew
M5 40mm DIN7984 Hex Screw
M3 14mm DIN7984 Hex Screw
M3 20mm DIN7984 Hex Screw
F695ZZ 5x13x4mm Bearing
Spring: Wire diameter 0.8mm, length 10mm, outer diameter 5mm
Button head screw assortment M3
Filament gear assembly
Optical Endstop

Klipper config (printer.cfg)

[filament_motion_sensor motion_sensor]
detection_length: 3
extruder: extruder
switch_pin: PA4
pause_on_runout: True

No

Yes

0.2

20

Print everything in PETG or a higher temp material. Do not use PLA as it will deform over time. Keep in mind that the encoder needs to be light blocking! Some of the PETG filaments will pass light so the sensor wont work! You can print the encoder with PLA. Supports only needed for the bottom case.