I recently finished a Filament Spool Scale project that mounts a Strain-Gauge sensor inside of a spool holder. By connecting this spool holde/strain-gauge to an Arduino NANO CPU (and small LCD display), you can have a continuous display of the filament-weight and filament-length-remaining values on a 4-line LCD display. This can really help prevent filament run-outs as you can easily verify you have enought filament on-board BEFORE you begin a long print!

The STL files here are for a printer frame mounted spool holder with the built-in strain-gauge load cell.

I wrote up an article on this project for Nuts and Volts Magazine that appears in 2019- issue 4. For complete technical details to this project, the on-line link to this article is found here: https://www.nutsvolts.com/magazine/article/build-a-3d-printer-filament-scale

Even if you choose not to read the complete article, full documentation including the parts list, design/build notes, additional STL files, and the Arduino Source code is available to everyone by clicking on the the "DOWNLOAD" button found on the first page of the the Nuts & Volts article page shown above.

11-16-2020 UPDATE: Rather than go to the Nuts & Volts web site for the article, you can also retrieve all of the documentation including firmware, assembly and build documents, STL files for the scale arm, STL files for a sloped panel mount, and STL files for a standalone enclosure by going to my GITHUB repository at: https://github.com/Ed-EE-Eng/Spool_Scale_Project

The STL and assembly document files can be easily found in the GITHUB file folder called "extra".

Happy Weighting! Happy Printing!