Prusa Mk3 indirect filament sensor for all filaments (transparent, black, shiny, whatever).

I think the Prusa Mk3 filament sensor is a great idea. However, some filament types are difficult for the sensor to detect. There have been various efforts to develop indirect sensors that rely on sensing a proxy (usually a bearing) that moves with the filament. The filament sensor is optimised for reading stainless steel surfaces, so a ball bearing is ideal. However, many of these require firmware modification (https://www.thingiverse.com/thing:3091625, https://www.thingiverse.com/thing:3178706