Node Configuration

The Hublink node uses a meta.json file on the SD card to configure node behavior and store metadata. The file uses JSON format:

{
  "hublink": {
    "advertise": "HUBLINK",
    "advertise_every": 300,
    "advertise_for": 30,
    "try_reconnect": true,
    "reconnect_attempts": 3,
    "reconnect_every": 30,
    "upload_path": "/FED",
    "append_path": "subject:id/experimenter:name",
    "disable": false
  },
  "subject": {
    "id": "mouse001",
    "strain": "C57BL/6",
    "strain_options": [
      "C57BL/6",
      "BALB/c",
      "129S1/SvImJ",
      "F344",
      "Long Evans",
      "Sprague Dawley"
    ],
    "sex": "male",
    "sex_options": [
      "male",
      "female"
    ]
  },
  "experimenter": {
    "name": "john_doe"
  },
  "device": {
    "id": "046"
  },
  "fed": {
    "program": "Classic",
    "program_options": [
      "Classic",
      "Intense",
      "Minimal",
      "Custom"
    ]
  }
}

Hublink Settings

The settings below modify the Hublink node behavior. These settings take effect at hublink.begin() but can be overridden at runtime (refer to the HublinkAdvanced.ino sketch).

Setting	Description	Default
`advertise`	Custom BLE advertising name	HUBLINK
`advertise_every`	Seconds between advertising periods	300
`advertise_for`	Duration of each advertising period in seconds	30
`try_reconnect`	Enable/disable automatic reconnection attempts	`true`
`reconnect_attempts`	Number of reconnection attempts if initial connection fails	3
`reconnect_every`	Seconds between reconnection attempts	30
`upload_path`	Base path for file uploads in S3	/FED
`append_path`	Dynamic path segments using nested JSON values (e.g., “subject:id/experimenter:name”)	subject:id/experimenter:name
`disable`	Disable Hublink functionality	`false`

Device Identification

The device.id field provides a unique identifier for your node that appears in the dashboard. This helps distinguish between multiple nodes in your experiment.

Custom Metadata

You can add any additional JSON objects to track metadata about your experiment. The example above shows:

Subject information (ID, strain, sex)
Predefined options for strain and sex selection
Program settings with available options
Any other relevant metadata specific to your experiment