An ESP32-based 1-Wire interface supporting access with physical ethernet and MQTT protocol.

Overview

Hardware

Schematic

Key Features

• Access 1-wire devices via ethernet / MQTT protocol
• 4 independent 1-Wire channels with hardware bus masters
• Over-the-air (OTA) updates (web interface and espota protocol)
• Multiple independent 1-wire buses.
• Responsive web interface
  

Supported 1-Wire devices

• DS2401 / DS2411 (Silicon Serial Number)

  • Unique Unique 64-Bit Serial Code

• DS18B20 (Temperature sensor)

  • Configurable resolution temperature

• DS2438 (Smart Battery Monitor)

  • Temperature, VAD, VDD

Web-Interface

Default login:

• Username: admin
• Password: 1w-If

MQTT API

%topic% is a configurable prefix. Default: 1wIf

Commands

General MQTT topic for commands: %topic%/cmd

General MQTT topic for responses: %topic%/stat

Payload Format:

{
  "action": "<command>",
  ... action specific parameters / attributes ...
}

Command 'Restart'

Restart the entire system.

{
  "action": "restart",
}

Response:

{
  "action": "restart",
  "acknowledge": true
}

Command 'Scan'

Scan 1-wire buses for all available devices:

{
  "action": "scan",
}

Scan 1-wire buses for availability of a specific device:

{
  "action": "scan",
  "device_id": "01.D2C79A1A0000"
}

Scan 1-wire buses for availability of a specific device family:

{
  "action": "scan",
  "family_code": 40
}

The response lists all available devices and the supported attributes (for Read / Subscribe / Unsubscribe commands):

Example Response:

{
  "action": "scan",
  "devices": [
    {
      "channel": 1,
      "device_id": "01.D2C79A1A0000",
      "presence": true,
      "attributes": ["presence"]
    },
    {
      "channel": 1,
      "device_id": "28.8F0945161301",
      "presence": true,
      "attributes": ["presence", "temperature"]
    },
    {
      "channel": 2,
      "device_id": "26.563743020000",
      "presence": true,
      "attributes": ["presence", "temperature", "VAD", "VDD"]
    },
    ...
  ]
}

Command 'Read'

Read value(s) of a single 1-wire device:

{
  "action": "read",
  "device_id": "28.8F0945161301",
  "attribute": "temperature"
}

Example Response:

{
  "action": "read",
  "device": {
    "channel": 1,
    "device_id": "28.8F0945161301",
    "temperature": 24.75
  }
}

Read value(s) of a specific device family:

{
  "action": "read",
  "family_code": 40,
  "attribute": "temperature"
}

Example Response:

{
  "action": "read",
  "family_code": 40,
  "devices": [
    {
      "channel": 1,
      "device_id": "28.8F0945161301",
      "temperature": 24.75
    },
    ...
  ]
}

Also the presence of a device can be accessed via the read command using the attribute presence. This is similar to the scan command.

{
  "action": "read",
  "device_id": "28.8F0945161301",
  "attribute": "presence"
}

Example Response:

{
  "action": "read",
  "device": {
    "channel": 1,
    "device_id": "28.8F0945161301",
    "presence": true
  }
}

Command 'Subscribe / Unsubscribe'

Subscribe to cyclic updates for 1-wire device attributes. After successful subscription this triggers internally a Read command with the configured internal time.

Unit of 'interval': milliseconds

{
  "action": "subscribe",
  "device_id": "28.8F0945161301",
  "attribute": "temperature",
  "interval": 1000
}

Example response acknowledging the successful subscription:

{
  "action": "subscribe",
  "acknowledge": true,
  "device": {
    "device_id": "28.8F0945161301"
  }
}

Unsubscribe from the attribute:

{
  "action": "unsubscribe",
  "device_id": "28.8F0945161301",
  "attribute": "temperature"
}

It is also possible to subscribe to the attribute presence to get cyclic updates about the availability of dedicated devices:

{
    "action": "subscribe",
    "device_id": "01.D2C79A1A0000",
    "attribute": "presence",
    "interval": 2000
}

Example of the Read command for attribute presence cyclically triggered by the subscription:

{
  "action": "read",
  "device": {
     "device_id": "01.D2C79A1A0000",
     "presence": false
  }
}

Development

Software

# Build firmware
./build.sh

# Flash firmware + LittleFS filesystem
./flash-fs.sh

# Optional: Monitor via serial outputs
./monitor.sh

Run tests

cd test
pdm install --dev

# Create a test_env_config.yaml in the test directory
cp example_test_env_config.yaml test_env_config.yaml
# Adapt all MQTT / device settings test_env_config.yaml
vim test_env_config.yaml

# Execute tests
pdm run tests
# Alternative: with filter
pdm run tests -k "<test name filter>"

# Lint/Format of test implementations
pdm run lint
pdm run format

Hardware

• PCB designed with KiCad
• Production files created with KiCad plugin KiCAD JLCPCB tools