Filament Flow / Jam (runout) with microswitch

this is a simple (and flawed but functional) microswitch based filament sensor which detects whether filament is flowing, it is suitable for any 1.75mm filament.
I have connected it to an Arduino Nano.

the basic logic is a counter which resets on a "CHANGE" interrupt from the microswitch, if the counter reaches a threshold value then an output is pulled high (a buzzer in my case) but if the printer has some kind of pause method (door sensor on the UP BOX can be triggered with a relay) then the printer will automatically pause.


video of it in action: https://www.youtube.com/watch?v=68XpV7J-bkA (sorry about the vertical video)