Custom Snapmaker U1 Firmware

OpenSpool Format Design

U1-specific extensions to the OpenSpool NDEF JSON format for filament tags, written as an NDEF record with MIME type application/json to NTAG215/216 tags.

Payload Examples

{
  "protocol": "openspool",
  "version": "1.0",
  "brand": "Generic",
  "type": "PLA",
  "color_hex": "#FF0000",
  "min_temp": 190,
  "max_temp": 220,
  "bed_min_temp": 50,
  "bed_max_temp": 60
}

Using the non-standard OpenSpool subtype field it is possible to specify a material subtype:

{
  "protocol": "openspool",
  "version": "1.0",
  "type": "PETG",
  "subtype": "Rapid",
  "color_hex": "AFAFAF",
  "additional_color_hexes": ["EEFFEE","FF00FF"],
  "alpha": "FF",
  "brand": "Elegoo",
  "min_temp": "230",
  "max_temp": "260"
}

Field Reference

Required Fields:

• protocol - Must be “openspool”
• version - Specification version (e.g., “1.0”)
• type - Material type (PLA, PETG, ABS, TPU, etc.)
• color_hex - Color in hex format (#RRGGBB)

Optional Standard Fields:

• brand - Manufacturer name
• min_temp / max_temp - Nozzle temperature range in °C

Optional Extended Fields (U1-specific):

• bed_min_temp / bed_max_temp - Bed temperature range in °C
• subtype - Material variant (Basic, Rapid, HF, Silk, etc.)
• alpha - Color transparency (00-FF hex, default: FF)
• additional_color_hexes - Additional colors for multicolor spools (up to 4)
• weight - Spool weight in grams
• diameter - Filament diameter in mm (e.g., 1.75)

Snapmaker Orca Naming Convention

Snapmaker Orca requires filaments to follow this naming pattern: <brand> <type> <subtype>

Examples: Generic PLA Basic, Elegoo PETG Rapid