Filament motion sensor

This is a detector I designed to be able to see if my 1.75mm filament is actually moving. This is especially useful when troubleshooting filament feed issues. You can look at the extruder drive wheel, but that can spin without feeding filament. This uses half of a rubber band that you get on broccoli at the supermarket. It attaches with the bowden connector to my MK8 extruder from Geeetech. I am including the 123Design file so you can modify to fit your situation.

Each segment of the wheel represents about 7mm (7.15 to be exact) of movement.

There is a video of it in operation can be seen here https://youtu.be/JHtcuPsRDpk

Enjoy!