Homebridge Plugin for SGP30

This is a Homebridge plugin for SGP30 eCO2 and TVOC sensor, working on the Raspberry Pi 3.

It uses read() and write() syscalls on the I2C devices exposed by Linux's filesystem.

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
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
showTemperatureTile	Enable showing temperature tile in Home that represents TVOC	bool	false	N

If showTemperatureTile is true, a temperature tile will show up in Home with the TVOC in ppb scaled by a factor of ten (e.g. 25.2 C = 252ppb).

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
eCO2Topic	MQTT topic to which eCO2 data is sent	string	SGP30/eCO2	N
TVOCTopic	MQTT topic to which TVOC data is sent	string	SGP30/TVOC	N

Example Configuration

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

  "accessories": [
    {
      "accessory": "SGP30",
      "name": "SGP30",
      "enableFakeGato": true,
      "enableMQTT": true,
      "mqtt": {
         "url": "mqtt://192.168.0.38",
         "eCO2Topic": "sgp30/eCO2",
         "TVOCTopic": "sgp30/TVOC"
      }
    },
  ]
}

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 C program that communicates with the sensor.
  • 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 characteristic that enables Eve to keep a historical graph of air quality (i.e. eCO2).