Filament Roller IR Sensor Version 2

A Kickstarter campaign for this product is live:
https://www.kickstarter.com/projects/522476987/filament-roller
Make a donation and receive a finished Filament Roller. Thanks for your support~

This is a prototype IR sensor and alarm which detects the direction and speed of your filament spool. This sensor will sound an alarm when your spool stops due to filament-jamming, nozzle-clogging, extruder-grinding, motor-stalling, or out-of-filament.

This second version is a stronger and easier-to-build version. However it has larger parts that can only be printed on larger 3D printers. Without the PCB, you can use this item like a regular low-friction filament roller. This roller can hold spools that are 5-12cm in width.

Required parts:
608 ball bearings (4 ea)
M3 x 12mm screws (14 ea)
M3 x 18mm screws (2 ea)
M3 nuts (16 ea)
M3 x 30mm screws (4 ea)
M5 washers (4 ea)
M5 nuts (4 ea)

Optional parts:
Filament Roller control board (1 ea)
Small rubber bands (16 ea)
Large rubb