MMM-Bosch-BME680-sensor

This is a module for the MagicMirror².

It is designed for a Bosch BME680 sensor connected with i²c and retrieves:

• temperature
• humidity
• pressure
• AQI

It sends notifications that can be handled by other modules and/or have its own display:

Using the module

To use this module, add the following configuration block to the modules array in the config/config.js file:

var config = {
	modules: [
		{
			module: "MMM-Bosch-BME680-sensor",
			config: {
				updateInterval: 30 * 1000, // 1 minute
				animationSpeed: 1000,
				decimalSymbol: ".",
				showAqiAtLevel: 0, // Show Air Quality only if AQI is worst or equals to a level (0 to always displaying, undefined to never displaying)

				mock: false,
				i2cAddress: 0x76,
				offsetTemperature: 0,
				gasLimitLow: 5000, // Bad air quality limit (values from Bosch specs)
				gasLimitHigh: 50000, // Good air quality limit (values from Bosch specs)
			}
		},
	]
}

Nota: gasLimitLow and gasLimitHigh must be adjusted by experimentation.

Installation

cd ~/MagicMirror/modules # Change path to modules directory of your actual MagiMirror² installation
git clone https://github.com/seb-ma/MMM-Bosch-BME680-sensor
cd MMM-Bosch-BME680-sensor

If nodejs version is compliant:

npm install --no-audit --no-fund --no-update-notifier --only=prod --omit=dev

Else, a full install + rebuild dependency may be needed:

npm install --no-audit --no-fund --no-update-notifier; npm rebuild i2c-bus --update-binary

OS configuration related

To access to sensor values, it is necessary to have i²c drivers activated and permissions to communicate with.

On Raspberry OS:

Activate i²c:

sudo raspi-config

Then, enable i²c:

• Interfacing options
• P5 I2C Enable / Disable automatic loading of the I2C kernel module

And add your user in i2c group:

sudo adduser $USER i2c
sudo adduser $USER gpio

This module has dependency node-rpio. Requirements must be followed (see https://github.com/jperkin/node-rpio):

Add the following line to /boot/config.txt and reboot:

dtoverlay=gpio-no-irq

Enable /dev/gpiomem access:

cat >/etc/udev/rules.d/20-gpiomem.rules <<EOF
SUBSYSTEM=="bcm2835-gpiomem", KERNEL=="gpiomem", GROUP="gpio", MODE="0660"
EOF

Configuration options

To only have notifications sent (no display), don't set position for the module.

Option	Description
updateInterval	Optional How often does the data needs to be retrieved? Type: int (milliseconds) Default: 3000 milliseconds (3 seconds) 3 seconds is needed to have an accurate Air Quality Index (a longer interval will not be accurate for AQI)
animationSpeed	Optional Speed of the update animation. (Milliseconds) Type: int (milliseconds) Default: 1000 milliseconds (1 second)
decimalSymbol	Optional Decimal separator Type: string ("." or ",") Default: "."
showAqiAtLevel	Optional Show Air Quality only if AQI is worst or equals to a level Levels are: 0=Good, 1=Moderate, 2=Unhealthy for Sensitive Groups, 3=Unhealthy, 4=Very Unhealthy, 5=Hazardous (0 to always displaying, undefined to never displaying) Type: integer Default: 0
mock	Optional true to retrieve false data if no BME680 is plugged Type: boolean Default: false
i2cAddress	Optional i²c address of BME680 sensor Type: int (hexadecimal value) Default: 0x76
offsetTemperature	Optional Temperature offset to apply (useful if sensor is near a processor) Type: float (degree celsius) Default: 0
gasLimitLow	Optional Bad air quality limit Type: int Default: 5000 (from Bosch specs)
gasLimitHigh	Optional Good air quality limit Type: int Default: 50000 (from Bosch specs)

Sent notifications

When data are retrieved, notifications are sent to other modules with payload containing related value:

• INDOOR_TEMPERATURE
  • payload: value of temperature in celcius
• INDOOR_HUMIDITY
  • payload: value of humidity in percentage
• INDOOR_PRESSURE
  • payload: value of pressure in hecto pascal
• INDOOR_GAS
  • payload: value of gas resistance in ohm
• INDOOR_AQI_LEVEL
  • payload: level of Air Quality from 0 to 5
  • 0=Good, 1=Moderate, 2=Unhealthy for Sensitive Groups, 3=Unhealthy, 4=Very Unhealthy, 5=Hazardous
• INDOOR_AQI
  • payload: value of Air Quality in percentage (100% = max healthy)

ExpressApp

API point is available to retrieve data sensor as json response.

• Can be called by URL as GET request - ex: http://localhost:8080/bme680