Having a scale built into your spool holder is a cool idea. I came across a couple of posts about implementing a load cell and HX711 amplifier to measure spool weights as well as this article - with an Octoprint plugin : https://hackaday.com/2018/08/10/3d-printers-get-a-fuel-gauge-adding-a-filament-scale-to-octoprint/
I wanted a mount that would work with a Delta Printer - with 2040 linear extrusion and have a handy mount for a reference weight - in this case, 100 grams.
KNACRO HX711 amplifier + 5 kg load cell (4x M4 button screws - two for the top and two for the bottom (I'm guessing that most of the HX711 on Amazon are identical).
American Weigh Scales 100g OIML Class M2 Calibration Weight
Make sure to tap the holes and not overtighten. The holes are recessed to provide clearance for standard 1kg filament spools.
- There is a notch in the back for the wires - so if you sleeve, leave a gap. There should be ample clearance for the cable.
Both the top and bottom parts were printed with supports and a 4mm brim to ensure that the supports did not pull away (Cura set to 0.3mm distance for supports). Printed at 50 mm/sec because - PETG.