BME280 Python Driver

Python Driver for the BME280 Temperature/Pressure/Humidity Sensor from Bosch.

• Free software: BSD license

Full credit to https://github.com/IDCFChannel/bme280-meshblu-py for most of the logic, I simply packaged / tidied it.

Features

• i2c reading of the bme280 Temperature/Pressure/Humidity sensor
• munin plugins for graphing the results

Installation (Package)

For I2C access you must have the 'smbus' package available - for debian based systems install python-smbus. If you wish to compile it, the python package is smbus-cffi (https://pypi.python.org/pypi/smbus-cffi/)

Then:

pip install bme280

Unless you have setup a virtualenv you may need to use sudo. Also, if your smbus is installed globally then you need to use sudo or ensure your virtualenv has access to the global site packages.

Usage

Adafruit have a good run through of setting up their break out version of the bme280 at https://learn.adafruit.com/adafruit-bme280-humidity-barometric-pressure-temperature-sensor-breakout/wiring-and-test

You will need to know the i2c address being used by the bme280, it is usually 0x76 or 0x77. To verify which devices are connected you can use:

i2cdetect -y 1

Then:

$ read_bme280 --help

usage: read_bme280 [-h] [--pressure] [--humidity] [--temperature]
                   [--i2c-address I2C_ADDRESS] [--i2c-bus I2C_BUS]

optional arguments:
  -h, --help            show this help message and exit
  --pressure
  --humidity
  --temperature
  --i2c-address I2C_ADDRESS
  --i2c-bus I2C_BUS

Example:

$ read_bme280 --i2c-address 0x77

1017.58 hPa
  50.55 ％
  19.03 ℃

Munin

Three plugins are available in the /munin folder. To use them link them into /etc/munin/plugins:

ln -s /path/to/bme280/munin* /etc/munin/plugins

You can configure the plugins by editing /etc/munin/plugin-conf.d/munin-node and adding:

[bme280_*]
group i2c
env.I2C_ADDRESS 0x77

You can test it with:

sudo munin-run bme280_humidity

If you get an error like:

/etc/munin/plugins/bme280_humidity: 21: /etc/munin/plugins/bme280_humidity: read_bme280: not found

Then Add the follow lines to /etc/munin/plugin-conf.d/munin-node under the [bme280_*] section you added before (assuming 'which read_bme280' results in /usr/local/bin/read_bme280):

env.PATH /usr/local/bin:/usr/bin:/bin

Restart your node and the new graphs should turn up in about 10 minutes:

sudo /etc/init.d/munin-node restart

Or you can force run munin a couple of times and they should turn up:

sudo su - munin munin-cron --shell=/bin/bash