Simple filament sensor adapted from my  favourite Voron filament sensor, for use on my modded Ender 3.

https://github.com/VoronDesign/VoronUsers/tree/master/printer_mods/JD/RefillPlease.

Also can act as a guide and reverse bowden mount.

From the git repo above:

You will need :

• 1 x micro switch (body : 20x6x10mm) with a lever (search for 'SPDT 5A, 125V 250V 29mm')
• 1 x JST 2 pins female connector
• 4 x M2x10 self tapping screws
• two piece of wire (30mm length each)
  
  And of couse 2xM3x10 and appropriate t-nuts.

Happy Printing