Elixir Bme680

An Elixir library to interface with the BME680 environmental sensor.

Installation

The package can be installed by adding elixir_bme680 to your list of dependencies in mix.exs:

def deps do
  [
    {:elixir_bme680, "~> 0.1.4"}
  ]
end

The Linux I2C driver needs to be installed for this library to work (e.g. libi2c-dev on Debian). If using Nerves, the driver should already be installed by default.

Usage

{:ok, pid} = Bme680.start_link()

measurement = Bme680.measure(pid)

# Measurement is like:
#
#   %Bme680.Measurement{
#     temperature: 21.74,
#     pressure: 1090.52,
#     humidity: 45.32,
#     gas_resistance: 10235
#   }
#
# Where temperature is in degrees Celsius, pressure in hPa, humidity in %
# relative humidity, and gas_resistance in Ohm

For more information, read the API documentation.

Note on gas resistance sensor warm up

Note that, due to the nature of the sensor, the gas resistance measurement needs a warm-up in order to give stable measurements. One possible strategy is to perform continuous meaurements in a loop until the value stabilizes (e.g. changing by less than 1% between consecutive measurements). That might take from a few seconds to several minutes (or more when the sensor is brand new), so it's adviseable to perform the measurement asynchronously to avoid blocking.

Acknowledgements

This project contains low-level code from the BME680 driver by Bosch