Filament Run Out Sensor

this is a simple filament run out sensor i was having problems when doing large prints that when my filament run out i had a failed print. so i designed this. it bolts on top of the extruder motor plate and is clean and minimalistic works really well simple to print.

Works with the KW11-3Z Switch
Purchase : https://www.ebay.co.uk/itm/KW11-3Z-Mini-Micro-switch-3pin-No-NC-with-comm-5A-250V-1-2mm-with-roller/261976763095?hash=item3cff082ad7:g:ll4AAOSw~gRVr1rS:rk:17:pf:0

And this is the Extruder plate that this works with
Purchase : https://www.amazon.co.uk/Extruder-Accessories-Upgraded-Replacement-Aluminum/dp/B07KX3Q8GF/ref=sr_1_fkmr1_4?ie=UTF8&qid=1547923929&sr=8-4-fkmr1&keywords=extruder+bowden+right+handed