Homebridge Plugin for Analog Soil Moisture Sensor

This is a Homebridge plugin for an analog soil moisture sensor, working on the Raspberry Pi 3.

The actual sensor values are read in by an Arduino, communicated to an Onion Omega2 over UART, and then sent over MQTT to a Raspberry Pi.

Configuration

Field name	Description	Type / Unit	Default value	Required?
name	Name of the accessory	string	—	Y
maxAnalogReading	Maximum analog reading (i.e. reading when soil is wet)	int	1024	N
minAnalogReading	Minimum analog reading (i.e. reading when soil is dry)	int	0	N
moistureThreshold	Threshold at which to notify that plant is too dry	int	25	N
timeout	Time since last data received until setting "Not responding" status	int (min)	5	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
mqttConfig	Object containing some config for MQTT	object	—	N

The mqttConfig object is defined as follows:

Field name	Description	Type / Unit	Default value	Required?
url	URL of the MQTT server, must start with mqtt://	string	—	Y
soilMoistureTopic	MQTT topic to which soil moisture data is received from Onion	string	soil_humidity	N

Example Configuration

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

  "accessories": [
    {
      "accessory": "Soil Moisture Sensor",
      "name": "Pothos",
      "maxAnalogReading": 800,
      "minAnalogReading": 200,
      "moistureThreshold": 25,
      "timeout": 5,
      "enableFakeGato": true,
      "mqtt": {
        "url": "mqtt://192.168.0.38",
        "soilMoistureTopic": "plants/soilmoisture"
      }
    },
  ]
}

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.
  • arduino contains code that runs on the Arduino and reads in an analog value from a pin and transmits that data over UART to the Onion.
  • python contains code that runs on the Onion, reading data over UART from the Arduino and transmitting that data over MQTT to the Raspberry Pi.