A filament monitor that pauses the print when your filament runs out and lets you restart it.


Pause printing when the 3D printer runs out of filament.


Inspired by and based on the work by

OctoPrint-FilamentSensor-ng plugin by Red-M found here


After installation, configure the plugin via OctoPrint Settings interface.

The pin being used needs to be entered by name (e.g. PA01, PC07).


OrangePI OS Configuration

Since we are accessing the GPIO as a non root user we need to configure the OS to allow this. Here’s the copy of the library documentation on how to do it:

If you want to be able to use the library as a non root user, you will need to setup a UDEV rule to grant you permissions first. This can be accomplished as follows:

 $ sudo usermod -aG gpio <current_user>
 $ sudo nano /etc/udev/rules.d/99-gpio.rules

That should add your user to the GPIO group, create a new UDEV rule, and open it in the Nano text editor. Enter the following into Nano

   SUBSYSTEM=="gpio", KERNEL=="gpiochip*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys/class/gpio/export /sys/class/gpio/unexport ; chmod 220 /sys/class/gpio/export /sys/class/gpio/unexport'"
   SUBSYSTEM=="gpio", KERNEL=="gpio*", ACTION=="add", PROGRAM="/bin/sh -c 'chown root:gpio /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value ; chmod 660 /sys%p/active_low /sys%p/direction /sys%p/edge /sys%p/value'"

press ctrl-x, Y, and ENTER to save and close the file. Finally, reboot and you should be ready to use OPi.GPIO as a non root user.

Issues with OPI GPIO library

https://github.com/rm-hull/OPi.GPIO/pull/28 solves the issues with PI GPIO library and the race condition that was preventing normal operations. It is available in release v0.3.4 and up so make sure you have latest OPI GPIO library. To upgrade to latest OPI GPIO library login to your octoprint server as user pi and execute:

 $ cd OctoPrint/
 $ venv/bin/pip install --upgrade OPi.GPIO


Sensor Configuration