Is there a way I can track how much filament is left on a roll?
Either an add-on sensor I can build or software that will track how much is used vs how much is supposed to be on the roll?
Have a Prusa Mk4 and it’s working ok so far but been having trouble with very long prints so trying to figure out if my rolls have enough left
You could weigh it, but you’d have to know the specific spool weight. Some spools have a scale on the side giving a rough estimation on how much is left in grams, but you could only do this yourself if you knew how much was on it to begin with (calculating the volume left and printing a scale for example). Other than that… No. Have a new spool ready and wait until the old one is empty.