Filament Guide with Jam Sensor

There are two annoying situations that can ruin your prints: one is when the filament ran out and the other is when the filament gets jammed up and knotted to the spool. For the first issue, we have the filament out sensor thingy https://www.thingiverse.com/thing:2533511
Introducing a new filament guide that can detect jam and act on it. It resources to the roller type stop switch and wiring pi GPIO 2 off the Raspberry Pi as hardware solution.

The Octoprint uses the “Filament Sensor Reloaded” plugin to graciously pause the print to let you change filament but it only supports one sensor. If you only use the Filament Jam sensor (and not the Filament Out sensor), you can read the instruction from the plugin and done.

If you want to use both the Filament Out sensor (GPIO-0) and Filament Jam Sensor (GPI-2) then the solution (while waiting for the new plugin) is to use Raspberry shell script to detect the Filament Jam condition and turn off the printer when it occurs. The scr