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pimoroni-pico/micropython/examples/breakout_bme68x/README.md

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BME68X

Getting Started

Construct new PimoroniI2C and BreakoutBME68X instances:

from breakout_bme68x import BreakoutBME68X
from pimoroni_i2c import PimoroniI2C

PINS_BREAKOUT_GARDEN = {"sda": 4, "scl": 5}
PINS_PICO_EXPLORER = {"sda": 20, "scl": 21}

i2c = PimoroniI2C(**PINS_PICO_EXPLORER)
bme = BreakoutBME68X(i2c)

The breakout_bme68x module includes constants for the possible I2C addresses:

  • ADDRESS_DEFAULT
  • ADDRESS_ALT

Reading Data From The Sensor

The read method will return a tuple containing Temperature (degrees C), Pressure (Pa), relative humidity (%rH), and gas resistance (Ω) values, plus the status code and gas/measurement indexes:

temperature, pressure, humidity, gas_resistance, status, gas_index, meas_index = bme.read()

In all cases gas_index and meas_index will be zero, since these refer to the measurement profile used to gather the current readings. The MicroPython bindings currently only support a single measurement profile with a default of 300c for 100ms.

You can pass a custom temperature and duration into read:

temperature, pressure, humidity, gas_resistance, status, gas_index, meas_index = bme.read(heater_temp=250, heater_duration=50)

Configuring The Sensor

The configure method allows you to set up the oversampling, filtering and operation mode.

bme.configure(filter, standby_time, os_pressure, os_temp, os_humidity)

The breakout_bme68x module includes constants for these:

Filter Settings

  • FILTER_COEFF_OFF
  • FILTER_COEFF_1
  • FILTER_COEFF_3
  • FILTER_COEFF_8
  • FILTER_COEFF_15
  • FILTER_COEFF_31
  • FILTER_COEFF_63
  • FILTER_COEFF_127

Oversampling Settings

  • NO_OVERSAMPLING
  • OVERSAMPLING_1X
  • OVERSAMPLING_2X
  • OVERSAMPLING_4X
  • OVERSAMPLING_8X
  • OVERSAMPLING_16X

Mode Settings

  • SLEEP_MODE
  • FORCED_MODE
  • NORMAL_MODE

Standby/Output Data Rate Settings

  • STANDBY_TIME_0_59_MS
  • STANDBY_TIME_62_5_MS
  • STANDBY_TIME_125_MS
  • STANDBY_TIME_250_MS
  • STANDBY_TIME_500_MS
  • STANDBY_TIME_1000_MS
  • STANDBY_TIME_10_MS
  • STANDBY_TIME_20_MS

Defaults

bme.configure(FILTER_COEFF_3, STANDBY_TIME_1000_MS, OVERSAMPLING_16X, OVERSAMPLING_2X, OVERSAMPLING_1X)