Spool Bridge
NFC-tagged filament spools that check themselves in and out of inventory when the printer starts a job.
3D printer filament inventory goes stale the moment you have to update it by hand. This closes the loop: each spool carries an NFC tag pointing at its own record, and the printer reports consumption automatically as it prints.
It also has a maintenance story worth knowing about. Every official printer firmware update strips the configuration include this depends on, silently. There is now a repair script and a check for it, because the failure mode is not an error, it is inventory that quietly stops updating.
The demo runs a four colour print with no printer attached. Watch the active bay change and the grams come off whichever spool is currently extruding: that is the whole problem the bridge solves, because Moonraker tracks exactly one active spool and the machine has four bays. Without it the wrong spool is decremented for the entire print.
Details worth knowing
- 01Automatic consumption tracking wired through the printer's own API.
- 02NFC tags on physical spools that resolve to a per-spool URL.
- 03A repair script for the firmware updates that silently strip the required config, because the failure is invisible otherwise.