A simple end of filament switch based on the switch that is standard on the Creality CR-10. I connect it to the Raspberry Pi that powers the Octoprint server and use a plugin for that. It seems easier than connecting it to the main board and the later needs another main board since the original is so basic.

Just two thin wires that goes to the Raspberry and it's done. The switch is fixed in place with a little drop of Cyanoacrylat glue.

180226: Small change at in and out side to prevent binding of the filament.