BME-280 sensor device driver with Micropython and Linux support (I2C + SPI)

This driver runs on Micropython and on regular Python (e.g. Raspberry Pi or other Linux devices).

It has support for both I2C and SPI bus.

Example: I2C

import bme280

try:
    # Connect to BME-280 via I2C-0 hardware with default pinning:
    bme = bme280.BME280(i2cBus=0)

    # Alternatively:
    # Connect to BME-280 via I2C-0 hardware with custom pinning (not supported by all microcontrollers):
    #bme = bme280.BME280(i2cBus={ "index": 0, "scl": 1, "sda": 0 })

    # Alternatively:
    # Connect to BME-280 via software I2C with custom pinning (not supported by all microcontrollers):
    #bme = bme280.BME280(i2cBus={ "scl": 1, "sda": 0 })

    # Alternatively:
    # Connect to BME-280 via pre-initialized Micropython bus object:
    #bme = bme280.BME280(i2cBus=machine.I2C(0, ...))

    # Synchronously trigger a MODE_FORCED conversion and return the result.
    temperature, humidity, pressure = bme.readForced(filter=bme280.FILTER_2,
                                                     tempOversampling=bme280.OVSMPL_4,
                                                     humidityOversampling=bme280.OVSMPL_4,
                                                     pressureOversampling=bme280.OVSMPL_4)

    # See help(bme280.BME280) for documentation and more methods.

    # Print the result.
    print(f"{temperature:.1f} *C; {humidity * 100:.1f} % rel. hum.; {pressure / 100:.1f} hPa")

except bme280.BME280Error as e:
    print(f"BME280 error: {e}")

Example: SPI

import bme280

try:
    # Connect to BME-280 via SPI-0 hardware with default pinning and pin 5 as chip select:
    bme = bme280.BME280(spiBus=0, spiCS=5)

    # Alternatively:
    # Connect to BME-280 via SPI-0 hardware with custom pinning (not supported by all microcontrollers):
    #bme = bme280.BME280(spiBus={ "index": 0, "sck": 1, "mosi": 2, "miso": 3 }, spiCS=5)

    # Alternatively:
    # Connect to BME-280 via software SPI with custom pinning (not supported by all microcontrollers):
    #bme = bme280.BME280(spiBus={ "sck": 1, "mosi": 2, "miso": 3 }, spiCS=5)

    # Alternatively:
    # Connect to BME-280 via pre-initialized Micropython bus object:
    #bme = bme280.BME280(spiBus=machine.SPI(0, ...), spiCS=machine.Pin(5, ...))

    # Synchronously trigger a MODE_FORCED conversion and return the result.
    temperature, humidity, pressure = bme.readForced(filter=bme280.FILTER_2,
                                                     tempOversampling=bme280.OVSMPL_4,
                                                     humidityOversampling=bme280.OVSMPL_4,
                                                     pressureOversampling=bme280.OVSMPL_4)

    # See help(bme280.BME280) for documentation and more methods.

    # Print the result.
    print(f"{temperature:.1f} *C; {humidity * 100:.1f} % rel. hum.; {pressure / 100:.1f} hPa")

except bme280.BME280Error as e:
    print(f"BME280 error: {e}")

Example: Context Manager

The BME280 instance can also be used as Context Manager (Python with statement).

import bme280

try:
    with bme280.BME280(i2cBus=0) as bme:
        temperature, humidity, pressure = bme.readForced(filter=bme280.FILTER_2,
                                                         tempOversampling=bme280.OVSMPL_4,
                                                         humidityOversampling=bme280.OVSMPL_4,
                                                         pressureOversampling=bme280.OVSMPL_4)
        # ...
except bme280.BME280Error as e:
    print(f"BME280 error: {e}")

Example: Normal mode

The driver also supports normal mode, where the bme280 does all measurements on its own in the background. See the datasheet for more information about normal mode.

import bme280

try:
    with bme280.BME280(i2cBus=0) as bme:
        # Start in normal mode with specified measurement interval (standby time).
        bme.start(mode=bme280.MODE_NORMAL,
                  standbyTime=bme280.T_SB_10ms,
                  filter=bme280.FILTER_2,
                  tempOversampling=bme280.OVSMPL_4,
                  humidityOversampling=bme280.OVSMPL_4,
                  pressureOversampling=bme280.OVSMPL_4)

        while True:
            # Read the most recent values from the device.
            temperature, humidity, pressure = bme.read()

            # ... do something else here and let the bme280 run measurements in the mean time.

except bme280.BME280Error as e:
    print(f"BME280 error: {e}")

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.