Introduction: 3D Printer Filament FAULT Detector - Octoprint

About: Rochester e-Nable lab created and coordinates the e-NABLE ecosystem. We design, develop and deliver free mechanical hand and forearm devices to people who need them. We develop software to support Connnected…

Is running out of filament or tangled filament on the spool causing failed prints for you?

Melvin Cruz, Skip Meetze, and Jon Schull

Rochester e-NABLE Lab October 2017

Tom Sanladerer listed “filament tangled on the spool” as the number one filament problem causing failed prints in 3D printing. We would add “running out of filament” as being right up there for causing failed prints in our lab. Here’s the good news: If you have Octoprint set up, then we have a simple solution for detecting either out of filament or tangled filament conditions. The printer will pause and you can replace or untangle the filament and then resume the print!

A few months ago, Chris Riley posted a way to deal with out of filament using a 3D printed holder for a limit switch and a bit of fiddling with your Octoprint:

With our Octoprint setup and our design for a one switch holder, you can also detect tangled filament problems and save yourself lots of failed prints!

As with missing filament sensors, we have a switch that changes state when the filament goes missing. In addition, we have a hinged lever in the system that is held in place by a rubber band. A Tangled filament jam pulls the lever away from the switch, causing it to change state again.

This sensor will work fine with all filament sizes.


- 3D Printed Parts YouMagine

- 21mm Lever Arm Micro Switch Black KW12-3 ($10.58 for 20 pcs)

- (4) Zip ties (Medium Lenght)

- (2) Small Rubber Bands

Step 1: Assembling Parts and Setup

Get all the 3D printed parts together, make sure to sand any residuals or threads on the parts that could be interfere with the mechanism's movements.

Set up cable setup and soldering as shown in Chris Riley's video on YouTube.

Place the switcher in the box; it will only go one way.

Attach the sensor and the box firmly to the bracket using a zip tie.

Use filament to make a pivot for the lever.

Finally, use a rubber band to adjust the sensitivity of the jam sensor, two loops should be good, depending. (on the rubber band.)

Step 2: Octoprint Setup

If you don´t have an octoprint set up yet, you can follow this previous instructable:

Once you have set up the octoprint system, you'll need to install the plugin called "Filament sensor reloaded". Once it's installed, make sure to restart the system. Once restarted, go back to settings and look under plugins the tab for "Filament Sensor Reloaded" and configure it according the image shown.

Step 3: Demo and Assembly Timelapse

Visit our blog to follow further developments or iterations on this design!

Make It Move Contest 2017

Participated in the
Make It Move Contest 2017

Automation Contest 2017

Participated in the
Automation Contest 2017