Spool Inspector Help

The OLED screen shows real-time status information:

• Top line: Current weight in grams
• Top right: Current mode (WEIGH, NEW, or LOC) and WiFi icon
• Middle line: Status — "Ready", "Stabilizing...", "Scan 3/20", QR payload, or error messages
• Bottom line: Button labels (MENU on the left, MODE on the right). Labels change contextually in the menu, location picker, and empty-confirm screens.

Short press the right button (MODE) to cycle through three modes. The current mode is shown in the top-right of the display.

• WEIGHWeigh mode (default) — Place a spool, scan QR code, record weight. After weighing, you'll be prompted to update the spool's storage location.
• NEWNew Spool mode — For adding a new spool to your inventory. Place the spool, scan QR code, and the device calibrates the tare weight. Works for both brand new and partially used spools. Mode auto-resets to WEIGH after calibration.
• LOCSet Location mode — Scan a spool's QR code to change its storage location without weighing. Useful when moving a spool to or from a printer.

1. Place the spool on the scale with the QR label facing the camera.
2. Wait for stabilization — the device waits 1.5 seconds for the weight to settle.
3. Automatic scan — the camera focuses and scans the QR code. You'll see "Scan 1/20" counting up on the display.
4. Weight recorded — on success, a chime plays and the weight is sent to 3D Spool Tracker.
5. Location prompt — "Set location?" appears with the spool's current location. Left button = No (keep current), right button = Yes (pick a new one).
6. Pick location — if you chose Yes, press the right button to cycle through your storage locations. Press the left button to select the one currently shown.
7. Remove the spool — take it off and the device is ready for the next one.

If the QR code can't be read after 20 attempts, the device plays a failure tone and reports the weight without a spool ID. The camera automatically refocuses after 3 consecutive failed scans.

Use this when moving a spool to or from a printer without weighing it.

1. Short press the right button until "LOC" appears in the top right.
2. Place the spool on the scale and let it scan the QR code.
3. The device fetches your locations from the server and shows a picker.
4. Right button cycles to the next location. Left button selects the one currently shown.
5. The spool's location is updated in 3D Spool Tracker.

Your storage locations are managed in the web app under Locations. The device fetches the latest list each time you enter the picker.

When a spool weighs less than 10g of filament remaining (after subtracting the spool tare weight), the device will ask you to confirm whether the spool is empty.

• Left button (YES): Marks the spool as empty in your inventory (sets remaining to 0g).
• Right button (NO): Records the weight as-is and keeps the spool active.

If you remove the spool without pressing a button, it's treated as "No" — the weight is recorded normally.

Button actions depend on what's on screen (idle, menu, location picker, empty-confirm prompt, etc.). The idle behavior is below; in-context button mappings are shown in their own sections above and on the device itself.

On first power-on, the device automatically starts its WiFi captive portal — you do not need to press any buttons to launch setup. The OLED shows "AP: SpoolInspector-Setup". What happens next depends on whether your device came pre-calibrated from me or you built it yourself.

If setup is incomplete on boot, the device plays a 5-tone rising melody as a reminder.

To recalibrate an already-calibrated device:

1. Clear the scale — make sure nothing is on it.
2. Short press the left button to open the menu.
3. Right button to scroll to Calibrate, left button to select. The device tares and shows "Place 100g weight / Press to continue".
4. Place a known 100g weight on the scale.
5. Press the right button — device calibrates and shows "Remove weight / Press to finish".
6. Remove the weight and press the right button — "Calibration done!"

Calibration is saved to flash and persists across reboots. You only need to recalibrate if the weight readings drift significantly.

1. Long press the left button (3 seconds) — the device starts a WiFi access point called "SpoolInspector-Setup".
2. Connect to that WiFi network from your phone or laptop.
3. A setup page should open automatically (captive portal). If not, go to 192.168.4.1 in your browser.
4. Enter your WiFi network name and password.
5. Enter your API Key — find this in your 3D Spool Tracker account under Settings > API Keys.
6. Save — the device will reboot and connect to your WiFi network.

The WiFi icon in the top-right of the display shows connection status: solid = connected, fast flash = connecting, slow flash = not configured. To change WiFi settings later, long press the left button again.

Short press the left button (MENU) from the idle screen to open the menu. Use the right button to cycle through items and the left button to select.

• Tare Scale — Zero the scale with an empty platform to correct drift.
• Calibrate — Start scale calibration. Follow the on-screen prompts with a known 100g weight.
• Settings — Camera Rotate 180° toggle (use if your camera is mounted upside down — persists across firmware updates) and other device settings.
• Update — Check the server for a new firmware version and apply it over-the-air.
• Refresh — Re-fetch your storage locations from the server.
• Test Mode — Continuous QR scan testing without sending data to the server. Useful for verifying camera placement and label readability.
• About — Firmware version, device ID, and status info.
• Back — Close the menu.

If WiFi is unavailable, the Spool Inspector queues weighings in flash memory and syncs them automatically when connectivity returns. No data is lost.

• The device stores the QR payload, weight, and operation type (weigh, calibrate, or mark empty).
• When WiFi reconnects, queued entries are sent one at a time (every 3 seconds) while the device is idle.
• Failed API calls are retried. Only permanent errors (4xx) discard an entry.

Each spool needs a QR code label for the camera to identify it. Print labels from the spool detail page in 3D Spool Tracker.

• Recommended printer: Niimbot B1 or similar thermal label printer (50x30mm labels).
• Label content: QR code with your spool URL, plus brand, material, and color info.
• Placement: Stick the label on the spool where the camera can see it when placed on the scale.
• Phone scanning: The QR code also contains a URL, so you can scan it with your phone camera to open the spool details page.

Go to My Devices in the user menu to see all Spool Inspector devices linked to your account.

• Friendly names — give each device a name like "Printer Room" or "Office" so you can identify them in usage history.
• Last seen — shows when each device last communicated with the server.
• Multiple devices — you can use the same API key across all your devices. Each device has its own unique device token.

If you've moved filament to a different brand's spool, the tare weight will be wrong. Update it in 3D Spool Tracker:

1. Go to the spool detail page and click Edit.
2. Change the Spool Weight dropdown to match the physical spool you're using.
3. Save — future weighings will use the correct tare weight.

Connect via USB Serial Monitor at 115200 baud: