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Workflow — Bambu Lab AMS

Bambu Lab support uses Home Assistant blueprints — no middleware and no UPDATE_TAG macro involved. Three blueprints handle the full flow: spool loading, dashboard display, and filament deduction.

For setup instructions, see the Bambu Lab AMS Integration guide.

Full Data Flow

Open full diagram

How It Works

Phase 1 — Spool Loading

  1. Scan a spool's NFC tag on the SpoolSense scanner
  2. The scanner publishes tag data (UID, material, color, temps) to MQTT and queries Spoolman for weight
  3. The loading blueprint triggers in HA when the scanner sensor shows "present"
  4. You load the spool into an AMS tray within 5 minutes
  5. The blueprint detects the tray change and:
    • Sends bambu_lab.set_filament to the printer (sets material, color, temps on the tray)
    • Sends cmd/tray_assign to the scanner (stores which UID is in which tray)
  6. The scanner queries Spoolman for the spool's remaining weight

Phase 2 — Dashboard Update

  1. The Bambu printer reports tray state changes to HA via the Bambu Lab integration
  2. The dashboard blueprint triggers on any tray state change
  3. It reads the current state of all tray entities (material, color, empty/loaded)
  4. Publishes the tray array to the scanner via cmd/tray_update
  5. The scanner renders the colored grid on the TFT display

Phase 3 — Weight Deduction

  1. A print finishes or is canceled on the Bambu printer
  2. The deduction blueprint triggers and reads per-tray weight usage from the print weight sensor
  3. For each tray that consumed filament, it sends cmd/deduct_tray to the scanner
  4. The scanner resolves the tray index to a spool UID (from the mapping stored in Phase 1)
  5. The scanner deducts the weight from Spoolman and updates the dashboard display

Key Points

  • No middleware, no Moonraker, no Klipper macros — entirely HA-driven
  • Per-tray weight deduction from Bambu's own print weight sensor
  • The scanner stores UID-to-tray mappings — no HA helpers needed
  • Supports up to 16 trays across 4 AMS units
  • Multi-color and multi-material prints are fully supported (each tray deducted independently)
  • Dashboard state is cached in NVS — persists across reboots
  • Writable tags (OpenPrintTag/OpenTag3D) get weight updated on next scan

Previous SVG Diagram

For reference, the original deduction-only workflow diagram:

Bambu Lab AMS workflow