Prusa MK3 Indirect filament sensor mod for stock extruder

I created this interposer to allow mounting my indirect filament sensor mod to the stock extruder. This simple mod fixes the laser filament sensor so it will work with all filament colors, even clear. It does this by using a simple proxy (small bearing) that travels with the filament. The laser sensor is actually designed to read stainless steel using its infrared laser, so this mod works reliably. I have been using this mod for months and printing tons of clear and other filaments without issue.

You can get the parts from my Skelestruder project or reverse Bowden. Grab the I-lid (or PI-lid if using MMU2) and the spring. You will need to purchase a single 673 (aka MR63) bearing.

Picture shows it mounted to R3 extruder, but will work with R2 as well.

Why an interposer? I decided not to make a custom version for stock because it would be a maintenance nightmare to keep it in sync with any improvements I make going forward. So I made this interposer to translate the mount to mine. See instructions below.