This is a very basic filament runout detection system that I originally designed for my Voron 2.4 r2 but would most likely work with any other printer (Solidworks file attached). It uses a basic Omron D2F style switch without it's metal arm (similar to klicky probe) and it simply gets pressed when filament passes by it and it just rides along as the filament gets pulled through. I love this design because you can find these switched anywhere, the one currently in mine is from a mouse I took apart from value village for a dollar. Mine is currently printed in Bambu Galaxy PLA but I'm sure nearly any filament would work. I placed it on it's side and printed with supports everywhere.
Thank you!!

Enjoy!!!