BME280 Sensor


The bme280 sensor platform allows you to read temperature, humidity and pressure values of a Bosch BME280 Environmental sensor connected via I2c bus (SDA, SCL pins). It allows you to use all the operation modes of the sensor described in its datasheet.

Tested devices:

Configuration

To use your BME280 sensor in your installation, add the following to your configuration.yaml file:

# Example configuration.yaml entry
sensor:
  - platform: bme280

Configuration variables:

  • name (Optional): The name of the sensor
  • i2c_address (Optional): I2c address of the sensor. It is 0x76 or 0x77.
  • i2c_bus (Optional): I2c bus where the sensor is. Defaults to 1, for Raspberry Pi 2 and 3.
  • operation_mode (Optional): Power mode for the sensor. Use 2 for forced mode or 3 for normal mode. Defaults to normal mode.
  • time_standby (Optional): Standby time in ms for normal mode of operation as described in the sensor datasheet. Defaults to 5 ms.
  • oversampling_temperature (Optional): Oversampling multiplier as described in the sensor datasheet. Can be 0 (no sampling), 1, 2, 4, 8, or 16. Default is 1.
  • oversampling_pressure (Optional): Oversampling multiplier as described in the sensor datasheet. Can be 0 (no sampling), 1, 2, 4, 8, or 16. Default is 1.
  • oversampling_humidity (Optional): Oversampling multiplier as described in the sensor datasheet. Can be 0 (no sampling), 1, 2, 4, 8, or 16. Default is 1.
  • filter_mode (Optional): IIR filter coeficient as described in the sensor datasheet. Default is 0, for filter off.
  • delta_temperature (Optional): Absolute delta for temperature correction.
  • monitored_conditions array (Optional): Conditions to monitor. Available conditions are temperature, humidity and pressure. By default all three are displayed.

Full Examples

If you want to specify the working mode of the digital sensor or need to change the default I2c address (which is 0x76), add more details to the configuration.yaml file:

# Example of customized configuration.yaml entry
sensor:
  - platform: bme280
    name: Ambient
    i2c_address: 0x77
    operation_mode: 2  # forced mode
    time_standby: 5
    oversampling_temperature: 4
    oversampling_pressure: 4
    oversampling_humidity: 4
    delta_temperature: -0.5
    monitored_conditions:
      - temperature
      - humidity
      - pressure
    scan_interval: 40

This sensor is somehow famous for generating relatively high temperature measurements compared to other sensors (it looks like self-heating does not feel good for some encapsulations). If you experience this problem, you can define an absolute delta of temperature correction using a negative number.

Customizing the sensor data

Give the values friendly names and icons, add the following to your customize: section.

# Example configuration.yaml entry
customize:
  sensor.ambient_temperature:
    icon: mdi:thermometer
    friendly_name: "Temperature"
  sensor.ambient_humidity:
    icon: mdi:weather-rainy
    friendly_name: "Humidity"
  sensor.ambient_pressure:
    icon: mdi:gauge
    friendly_name: "Pressure"

To create a group, add the following to your groups section.

# Example configuration.yaml entry
group:
  ambient_sensor:
    name: BME280 Environment sensor
    entities:
      - sensor.ambient_temperature
      - sensor.ambient_humidity
      - sensor.ambient_pressure

Directions for installing smbus support on Raspberry Pi

Enable I2c interface with the Raspberry Pi configuration utility:

# pi user environment: Enable i2c interface
$ sudo raspi-config

Select Interfacing options->I2C choose <Yes> and hit Enter, then go to Finish and you’ll be prompted to reboot.

Install dependencies for use the smbus-cffi module and enable your homeassistant user to join the i2c group:

# pi user environment: Install i2c dependencies and utilities
$ sudo apt-get install build-essential libi2c-dev i2c-tools python-dev libffi-dev

# pi user environment: Add homeassistant user to the i2c group
$ sudo addgroup homeassistant i2c

# pi user environment: Reboot Raspberry Pi to apply changes
$ sudo reboot

Check the i2c address of the sensor

After installing i2c-tools, a new utility is available to scan the addresses of the connected sensors:

$ /usr/sbin/i2cdetect -y 1

It will output a table like this:

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- 23 -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: 40 -- -- -- -- -- UU -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- 77

So you can see the sensor address what you are looking for is 0x77 (there are more i2c sensors in that Raspberry Pi).