Christopher Robertson has created a new 3D printer filament roller and feeder which offers an all-in-one IR sensor and alarm to detect all filament feeding errors automatically to help stop your ...

As the filament passes between the bearings, the arm raises and lowers the magnet, which is detected by a linear Hall-effect sensor.

When we see a filament sensor, it’s generally more of the “there/not there” variety to prevent a printer from blindly carrying on once the reel is spent.