Load Cell mod for IKEA Samla Filament Spool Roller

About

Load Cell mod for IKEA Samla Filament Spool Roller - if you know the spool weight and the total spool weight and diameter, then you can estimate how much filament is left.
This helps in planning what else you can print minimizing waste or predict the moment when you need to swap the spools.

Please give a like and post makes and provide comments for further improvements.

Changelog
- 2025.02.16 added B version - with 10mm distance between small holes with M4 only holes, 44mm diameter between internal holes (MakerBotics version)
- 2025.02.16 renamed initial release as A version, see ‘Dimensions’ section below
- 2024.10.21 initial release, with a bit of things to be cleaned up in the upcoming week

Todo
- HomeAssistant integration + Grafana metrics and dashboard to see filament left ( got working setup but may need more tuning or referring to GitHub?)

- maybe add models for other load cell sizes, looks like 13x13x80mm load cells are getting less common

Dimensions

- load cell sizes:
  - A version - 12x12x80 mm, distance between the holes in the middle 40mm, distance between the holes closest to each other 15mm, hole sizes 4mm top, 6mm bottom
  - B version - 12.7x12.7x75mm, distance between the holes in the middle 44mm, distance between the holes closest to each other 10mm, hole sizes 4mm top, 4mm bottom
- total height of the spool roller from the bottom to the top ~ 45mm
- other dimensions left as is (180mm length, 95mm width) 

Requirements

- 4x 608ZZ bearings
- 4x insets from original model to put into the 608ZZ bearings
- print top and bottom of this model
- 529 HX711 load cell amplifier + load cell with 5kg range where load cell is 13x13x80mm in dimension (or 10kg, but anything higher gets less precise) or 1-20kg version
- 2x M4x12 or longer + 8 washers (2 under the screw heads, the rest as the extra distance)
- 2x M6x12 or longer + 2 washers
- ESP32 with ESPHome which supports HX711, integrates with HomeAssistant (or whatever you have)
- optionally use Octoprint plugin - Filament Scale

Print

- model names without any prefix are for A version
- model names with 10mm prefix are for B version
- print top and bottom, recommended 4 perimeters 0.2mm layer height, 20% infill, PETG
- see attached 3mf file for additional suggestions related to reinforced areas around the holes
- notice gcode contains moves for my custom timelapse video capture (print head moves to back and then to Z axis), so provided gcode file is just for rough estimation of the print time + required filament,

Assembly

- make sure to place the load cell properly according to the specs (the arrow should point downwards)
- the easiest way to assemble it is to attach the bottom to the load cell and then place everything on the side and screw it together
- more details about the project here.

 If you add Prometheus exporter to HomeAssistant, then you can scrape the metrics and use them in Grafana as dashboard.