Barometric Pressure (BMP280, BME280)

The BMP280 and BME280 are barometric pressure sensors with a measurement range of 300hPa to 1100hPa. Both sensors are also equipped with temperature sensors, and the BME280 is additionally equipped with a humidity sensor.

By utilizing the fact that atmospheric pressure changes with altitude, we can use the pressure reading to estimate our altitude. These sensors are precise enough to detect changes of as little as 10cm in altitude (...though due to noise, you really need about a meter change in altitude for the changes to be discernible).

Identifying Device

Some sellers will try to pass off a cheaper BMP280 as the (slightly) more expensive (BME280). See the image at the top of this page; both devices are labeled as 'BME/BMP280', but only the device on the right is an actual BME280.

To identify the device, pay close attention to the sensor chip; the BMP280 chip is rectangular with a hole at the corner, while the BME280 is square with a hole at the center of one side.

Pins

Wiring

Code

This code will print the pressure and altitude every second.

Blocks

Python

BMP280

import machine
import bmp280
import time

i2c0 = machine.I2C(0, freq=100000)
bmp280_device = bmp280.BMP280(i2c0, addr=118)
while True:
    bmp280_device.read()
    print('Readings:')
    print(bmp280_device.get_pressure())
    print(bmp280_device.get_altitude())
    time.sleep(1)

BME280

import machine
import bme280
import time

i2c0 = machine.I2C(0, freq=100000)
bme280_device = bme280.BME280(i2c0, addr=118)
while True:
    bme280_device.read()
    print('Readings:')
    print(bme280_device.get_pressure())
    print(bme280_device.get_altitude())
    time.sleep(1)

Results

You should see the sensor readings printed in the monitor.

As you move the sensor up and down (...at least a meter), you should see the readings change.

class BMP280 / class BME280 - control BMP280 and BME280 barometric pressure sensors