7. BME280

BME280 is an environmental sensor with temperature, humidity, and air pressure integrated. High precision, multi-functional, small size and other characteristics. This sensor is ideal for all kinds of weather / environmental sensing. Accuracy for HUmidity is ± 3%, absolute air pressure is ± 1 hPa, temperature is ± 1.0 ° C. Since the pressure changes with altitude, the pressure measurement result is very good, you can also use it as an altimeter with ± 1 meter or higher accuracy！

Important

The BME280 chip is built-in in the mPython Board but the default configuration is without this BME280 environmental sensor. Then, you can the BME280 module to connect to it via the mPython Expansion Board. The I2C pin is merged into the bus, that is P19(SCL)、P20(SDA).

7.1. Get temperature, humidity, pressure

An example of obtaining BME280 temperature, humidity, air pressure and displaying it on the OLED screen:

from mpython import *              # import the mpython module

while True:
    oled.fill(0)                   # clear screen
    oled.DispChar("BME280",10,0)
    oled.DispChar("温度：%0.1f C" % bme280.temperature(),10,20)   # obtain BME280 temperature in Celsius
    oled.DispChar("湿度：%0.1f %%" % bme280.humidity(),10,34)     # obtain BME280 humidity in %
    oled.DispChar("压强：%0.1f KPa" % (bme280.pressure()/1000),10,48)  # Get BME280 pressure in Pa, here we show that except 1000 go to KPa
    oled.show()   # refresh screen
    sleep(2)      # delay 2 seconds

The BME280 class has been instantiated by the mPython Board, just use the BME280 object. To obtain the temperature value, use the temperature() function in Celsius To obtain the humidity value, use``humidity()`` , in %. To obtain the atmospheric pressure, use pressure() , in Pa(Pa).

7.2. mPython Expansion Board applications

Here you have learned how to get the weather data of BME280. Further thinking, how to use meteorological data and how to send it? You can use the http Server you learned earlier for remote access or use the mqtt protocol to push data to the server.