Spool Inspector
Place a spool on the scale. The Inspector scans the QR code, weighs the spool, and syncs everything to your account in seconds. Remaining filament, project costs, even storage location — all without touching your phone.
Hardware
How it works
Place spool on the scale
The scale detects weight over 50g and begins stabilizing.
Camera scans QR code
The autofocus camera locks onto your QR label and reads the spool ID.
Data syncs instantly
Weight, remaining filament, and project costs update in your account automatically.
Set location (optional)
A prompt asks if you want to update the spool's storage location. Pick from your list or skip.
Remove spool
Take the spool off. The station resets and is ready for the next one.
Features
Automatic QR Scanning
Place a spool on the scale and the autofocus camera reads its QR code automatically — no manual entry needed.
Precision Weighing
A load cell weighs down to the gram. The system subtracts the spool tare weight to calculate remaining filament.
Instant Sync
Weight readings sync to your account in real time. Remaining filament, project usage, and material costs all update automatically.
Set Spool Location
Update a spool's storage location right from the device. Moving a spool to the printer? Scan it and set the location — no need to open the app.
Near-Empty Detection
When a spool has less than 10g remaining, the device prompts you to mark it as empty. Never start a print with an empty spool again.
Three Modes
Cycle between Weigh (update inventory), New Spool (calibrate tare weight), and Set Location (move spools between locations) with a single button press.
Offline Queue
No WiFi? No problem. Weighings are saved to flash memory and sync automatically when connectivity returns. No data is ever lost.
OLED Display
A built-in display shows weight, current mode, scan progress, WiFi status, and prompts — no phone or computer needed to operate.
Easy WiFi Setup
Long press a button to start the captive portal and enter WiFi credentials. Then either paste an API key in the portal or scan a QR from Settings to pair the key — your call.
Button reference
OLED indicators
Specifications
Bill of materials
Estimated total parts cost: ~$60 (excluding tools and 3D printing filament). Or get a complete kit from 3dcreator.shop.
Some links below are affiliate links. We may earn a small commission at no extra cost to you.
Headers, fasteners, and wire typically sold in bulk packs. This crimper kit (paid link) includes the crimper, housings, and pins. Or skip the crimping and grab a pre-made cable set from 3dcreator.shop.
Important: Direct-wire the load cell
Do not use Dupont connectors on the load cell wires. Solder them directly to the PCB pads. Dupont connectors cause intermittent contact issues that lead to weight drift and unstable readings. The OLED and button connectors are fine — this only applies to the load cell.
STL files provided. ~450g of filament total. Don't have a 3D printer? Get the pre-printed parts from 3dcreator.shop.
Most 3D printing hobbyists already have these tools
Thermal label printer for printing QR code spool labels. Works with our label export feature.
Get one
Every part you need to build a Spool Inspector — source nothing yourself. Already have some parts? Exclude them at checkout and pay less.
- ✓All electronics, hardware, and connectors
- ✓Base PCB set included
- ✓Optional add-ons: pre-crimped cables, USB, scale
- ✓Customize — exclude items you already have
- ✓You 3D print the enclosure (STLs provided)
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