Filament Jam Sensor

A simple mechanical filament jam sensor for my Anet A8. It triggers if the filament is stuck on the roll or is under too much tension for other reasons. I use it with OctoPrint to pause the print if that happens.
You'll need a fitting end switch, I had a ZIPPY VMN around, so the mounting hole is for that model:
http://www.zippy.com.tw/sw/show_detail.aspx?ps_rfnbr=314
Feel free to drill matching holes for your type of sensor, or modify the design to fit your switch.

If you have OnShape, you