If you have a desktop 3D printer, you probably want something to hang filament spools on. [LVTRC] has a spool roller that fits the bill. It also incorporates a scale and a round touch screen. (Google Translate) We’ve seen those round screens before, and now we wonder why we didn’t think of this. The GC9A01 display shows a progress ring and lets you save settings or calibrations to EEPROM.
An Arduino Nano provides the brain, and the load cell connects to an HX711. The project is made to fit a specific printer, but it should be little trouble to adapt it to a different printer or to mount it in an external mount. One of the calibration steps, of course, is to program the weight of an empty spool to subtract from the total weight.
The device can store up to five specific profiles. Not the biggest spool holder we’ve seen. We keep thinking that we don’t know why we want a circular screen, and then someone always drops in to show us another thing we didn’t think about.