aaronhktan / homebridge-bmp280

A Homebridge plugin for the BMP280 temperature/barometric pressure sensor connected to Raspberry Pi over SPI. C, C++, and JavaScript.

Homebridge Plugin for BMP280

This is a Homebridge plugin for BMP280 temperature and barometric pressure sensor, working on the Raspberry Pi 3.

It communicates with the sensor using Linux's user-mode SPI API, spidev.

Configuration

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

Field name	Description	Type / Unit	Default value	Required?
name	Name of the accessory	string	—	Y
spidevInterface	Spidev interface in /dev/ that the sensor is mounted at	string	/dev/spidev0.1	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	bmp280/temeprature	N
pressureTopic	MQTT topic to which pressure data is sent	string	bmp280/pressure	N

Example Configuration

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

  "accessories": [
    {
      "accessory": "BMP280",
      "name": "BMP280",
      "enableFakeGato": true,
      "enableMQTT": true,
      "mqtt": {
          "url": "mqtt://192.168.0.38",
          "pressureTopic": "bmp280/pressure",
          "temperatureTopic": "bmp280/temperature"
      }
    }
  ]
}

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.
  • python contains a sanity test to make sure that the sensor is actually connected and is a BMP280.