filament watch dog, e-Stop

The filament sensor monitors both types of critical conditions: spool jam and thread break/end. It is mounted onto the bowen retainer, and is connected to filament sensor input. 

It also works as an poor man eStop button, need to press downwards on the leftmost fork (where filament enters the sensor)

Can be wired as both Normally Open and Normally Closed.

Left switch (NC) – watches end of filament event
Right switch (NO) – watches spool jam event

Sensor features rocker design, balanced under normal printing conditions. Sensitivity of the jam sensor can be adjusted by placing a counterweight nut (3/8" thread), and the angle between the spool and the sensor. The end-of-filament sensor requires no adjustments.

Setup:

• print 2 parts, insert threaded heatset (M3x5x4) into the base of upper part
• prepare and wire 2 switches, follow the wiring as in the picture, left NC, right NO
• screw both switches onto the bottom part (M2x10)
• assemble both parts around the bowen retainer (M3x8 – see pic), sensor should rock freely on the retainer
• adjust the position of your spool relative to the sensor, recommended average angle shall be 30-45 degrees
• no nut counterweight is normally required, but might be used to lower sensitivity of a jam sensor
• sensor is connected as the standard switch filament sensor between GND and Signal pins of the connector (i.e. Octopus  J33, pins 2,3)
• end-of-filament or jam event will PAUSE your printing session, get creative with the gcode handler, and share your ideas

Klipper configuration may look like:

[filament_switch_sensor YOUR_filament_sensor]
switch_pin: ^PG11 # Octopus
pause_on_runout: True
insert_gcode:
   M117 Insert Detected
   # your gcode here
runout_gcode:
   M117 Runout Detected
   # your gcode here

• Remember to specify pull-up resistor (^) if your wiring is made for NO sensor

Make sure to get acquainted with A.Ellis's macros -- https://ellis3dp.com/Print-Tuning-Guide/articles/useful_macros/pause_resume_filament.html

Let me know of any questions, and please share your gcode suggestions