DIY filament runout sensor

I wanted to get a filament runout sensor for my Mercury ZeroG, but didn’t want to buy a cheap off the shelf one that would ultimately fail, so made one using a Creality end stop switch.

I liked the concepts of the ones online, however I wanted to use a Y-adaptor so I could have another filament prepped and primed ready to go, rather than get flustered feeding new filament whilst the print times out.