Filament runout sensor

I designed this runout sensor to be used with some of the opto endstop LED switches I had in the drawer.
The design uses a 688 bearing and a custom PTFE holder to allow filament to glide through with minimal friction.
If you desire, you can make a hole in the base for attach it to the 3Dprinter.
You can print the whole sensor within 20mins. 14 for the base, and 6 for the spring.

.STL files:
Filament sensor base.
Spring for the base.

Parts you need:
Opto endstop switch.
20mm PTFE tubing.
Standard 688 bearing. Inner is 8mm and outher is 16mm.

Making the PTFE guide:
Cut the PTFE tube to the same size as the holder with springs.
Cut it in half and adhere PTFE tube to the holder with superglue and allow to dry.

Wiring guide:
The pins on the opto endstop are labelled as S, G, and V.
The LED will light up when the filament runs out, so connect +5v to V and ground to G.
Connect pin S to the port configurated in your marlin configuration file for your printer.