Simple Filament Sensor

Couldn't find the sensor i was searching for.
Well, build it. This is yours!
Wanted it closest to the extruder motor.
Designed it to slot into the 2020 rod.
You need:
ptfe-tube (6cm, 4mm dia) right into the extruder hole.
2 M3 screws 10mm with nuts.
and a Micro-switch with a roll at the end of the arm.

After I tried several kind of designs, this is the V5.
With the pictures and actually i am using V5 myself, just put a little shrink-tube into the ptfe slot to have a tighter fit.
It'