Anet a8 Mk8 extruder arm with filament runout sensor

This is a remix of two parts by two seperate designers. I have taken these two very well designed items, and used the best of both in one part. I didn't like the idea of having the sensor either just floating on the filament pre-extruder, and also didn't like the idea of having it fixed to the frame pre-extruder. Having it a part of the only moving item pre-extruder is the most ideal and efficient way to to mount it.
The filament runout sensor part has a modified 4mm hole, to install 2"-3" of P