Bestagon Filament Sensor

Don't want to make it yourself! I sell these! (US only for now): https://www.snrtechbytes.com/product-page/bestagon-micro-filament-runout-switch

Another filament sensor! This is an extremely small filament sensor that uses an Omron micro switch and a 5.5mm ball bearing, prints completely without supports and inspired by best shape found in nature. It uses 2 ECAS fittings and is designed to connect in line in any PTFE tubing wherever you want. It's so light no mounts are really needed however there are 2 spots for brass inserts if you decide you do want to mount it. 

There are two versions, the JST version which has a little spot to mount a JST plug if you want this thing quickly removable, or one without where you are expected to solder your wires directly to the Omron switch.

Bill of Materials

5.5mm ball bearing

m2x10 self tapping screws

Omron D2f microswitch (no lever or be sure to remove the lever!)

2 ECAS fittings

OPTIONAL: 

2 pin 2.54mm JST-XH header