Spool Inspector: The Smart Scale for 3D Filament

Spool Inspector is a filament weighing station that automatically tracks your 3D printer filament inventory. Place a spool on the scale, and it scans the QR  code, weighs the spool, calculates remaining filament, and syncs everything to your free 3D Spool Tracker account at 3dspooltracker.com — all in seconds, without touching your phone or computer.                    

  How it works:

  1. Print QR labels for your spools from the web app

  2. Place a spool on the scale                                                 

  3. The camera scans the QR code and autofocuses

  4. Weight is measured and filament remaining is calculated automatically      

  5. Data syncs to your account over WiFi in real time                          

  Go to https://3dspooltracker.com/spool-inspector for more details

  Features:                                                                     

  - Autofocus camera for reliable QR scanning                            

  - WiFi connected with automatic cloud sync                                    

  - Offline queueing — never lose data if WiFi drops                               

  - OTA firmware updates from the web                                           

  - Near-empty spool detection with on-screen prompt                            

  - Captive portal WiFi setup — no coding required

  - Print labels from a label printer or standard printer using Avery labels

  - Track filament location - in storage or in printer

  - Print labels ahead of time and sync to spools later                              

  What you will need:                                                                

  - This 3D printed enclosure 

  - PCB set ($12 at 3dcreator.shop)                       

  - Seeed XIAO ESP32S3 Sense                                                    

  - OV5640 camera module                                                        

  - SSD1306 0.96" OLED                                                          

  - 5kg load cell                                                               

  - Piezo buzzer, buttons, headers, fasteners                                   

  - Free account at https://3dspooltracker.com                                          

  Full BOM with costs (~$53 total), build guide, and instructions at 3dcreator.shop/docs/spool-inspector/build-guide           

  YouTube walkthrough of the build at https://youtu.be/xA8yw1Eb52s 

*** Note - in the video, I connect the load cell to the PCB using a Dupont connector.  After spending a solid day chasing down an issue, I would suggest direct soldering the load cell to the PCB.   *** 

  The web app is completely free — unlimited weighing, spools, projects, QR labels, CSV export and Import, community filament catalog with 1,500+ presets, and more. No  subscription required.