This is my version of a filament sensor install on a direct drive Ender 3.
This is made to fit any of the chinese filament sensor (photo attached) you can find on Aliexpress for less than 2 euro.

When using a direct drive the feeding system needs to be taller than the frame and slightly on the front to avoid interference with cables and high feeding angles when printing tall stuff.

For this reason I decided to reuse my abandomned stock spool holder that is solid and tall.

The reverse bowden has the purpose of reducing the air exposure of the filament, that in my case is contained in a dehydrator (mandatory for PETG). It also allows to place the filament box wherever you want without thinking about feeding angles.

This is a remix of a good roller I found, so I will also add the original files just to have everything in one place.
Thanks to the creator!

Printing note: I printed it upside down with supports only on the ring side. Everything else is printable with bridges. If you have tested good overhang angles, you can support only the side of the ring that doesn't touch the plate.

Another note: Please double check the hole for the bowden attach, there are two types with different diameter, pick the smallest one and measure the hole because mine was too small and had to use the deburring tool to enlarge it.

Hope you like it!