/homebridge-bme280

A Homebridge plugin for the BME280 temperature/humidity/barometric pressure sensor connected to Raspberry Pi over I²C. C, C++, and JavaScript.

Primary LanguageC

Homebridge Plugin for BME280

This is a Homebridge plugin for BME280 temperature, humidity, and barometric pressure sensor, working on the Raspberry Pi 3.

It communicates with the sensor using Linux's user-mode I2C API, i2c-dev.

Configuration

Before running this plugin, you must add the homebridge user to the i2c group so Homebridge can access the i2c-dev interface. sudo adduser homebridge i2c

Field name Description Type / Unit Default value Required?
name Name of the accessory string — Y
i2cAdaptor i2cdev interface in /dev/ that the sensor is mounted at string /dev/i2c-3 N
enableFakeGato Enable storing data in Eve Home app bool false N
fakeGatoStoragePath Path to store data for Eve Home app string (fakeGato default) N
enableMQTT Enable sending data to MQTT server bool false N
mqttConfig Object containing some config for MQTT object — N

The mqttConfig object is only required if enableMQTT is true, and is defined as follows:

Field name Description Type / Unit Default value Required?
url URL of the MQTT server, must start with mqtt:// string — Y
temperatureTopic MQTT topic to which temperature data is sent string bme280/temeprature N
pressureTopic MQTT topic to which pressure data is sent string bme280/pressure N
humidityTopic MQTT topic to which humidity data is sent string bme280/humidity N

Example Configuration

{
  "bridge": {
    "name": "Homebridge",
    "username": "XXXX",
    "port": XXXX
  },

  "accessories": [
    {
      "accessory": "BME280",
      "name": "BME280",
      "enableFakeGato": true,
      "enableMQTT": true,
      "mqtt": {
          "url": "mqtt://192.168.0.38",
          "pressureTopic": "bme280/pressure",
          "temperatureTopic": "bme280/temperature",
          "humidityTopic": "bme280/humidity"
      }
    }
  ]
}

Project Layout

  • All things required by Node are located at the root of the repository (i.e. package.json and index.js).
  • The rest of the code is in src, further split up by language.
    • c contains the C code that runs on the device to communicate with the sensor. It also contains a simple program to check that the sensor is attached and readable.
    • binding contains the C++ code using node-addon-api to communicate between C and the Node.js runtime.
    • js contains a simple project that tests that the binding between C/Node.js is correctly working. It also contains a custom characteristic that allows Eve to keep barometric air pressure data.