3.28 Environment Monitoring

3.28.1 Overview

In this project, we use an OLED display to reveal the values of temperature, humidity, air pressure and altitude in the environment. It can be regarded as a mini environmental monitoring device.

3.28.2 Test Code

Code:

In Files, open 3-28-environmentalMonitoring.py and click .

'''
 * Filename    : 3-28-environmentalMonitoring
 * Thonny      : Thonny 4.1.4
 * Author      : http://www.keyestudio.com
'''
import machine
#import I2C and Pin from machine module
from machine import I2C, Pin
#import AHT20 from aht20 library
from aht20 import AHT20
#import BMP388 from BMP388 library
from bmp388 import BMP388
from oled import OLED
import time

#create an I2C object and add SDA and SCL pins
i2c = I2C(scl=Pin(22), sda=Pin(21))
#create an AHT20 object and initialize I2C object to communicate with AHT20 sensor via I2C bus
sensor = AHT20(i2c)

# create a BMP388 object and set SDA and SCL pins, set IIC frequency to 100KHz
i2c = machine.SoftI2C(scl=machine.Pin(22), sda=machine.Pin(21), freq=100000)

# create a BMP388 object and send i2c object to it to communicate with the BMP388 sensor via the I2C bus, set the BMP388 IIC address to 0x76
bmp = BMP388(i2c, i2c_addr=0x76)

# create an OLED example
oled = OLED(i2c)
# clear oled
oled.clear()
'''
str() function converts a variable of type string from a variable of another type
int() function converts a variable of another type to a variable of type int. The reason for this conversion is that there is no data display after the decimal
pressure unit conversion：1 hPa = 1 × 100 Pa = 100 Pa

'''

while True:	
    try:
        #Store the values of temperature and humidity in the temperature and humidity variables
        temperature, humidity = sensor.read_temperature_humidity()
        # read the pressure
        pressure = bmp.read_pressure() // 100 #Convert Pa to hPa by dividing the pressure by 100        
        # clear display
        oled.clear()
        # show pressure
        oled.show_text("Pressure:", 0, 0)
        oled.show_text(str(int(pressure)), 70, 0)
        oled.show_text("hPa", 105, 0)
        # show temperature
        oled.show_text("Temperature:", 0, 15)
        oled.show_text(str(int(temperature)), 100, 15)
        oled.show_text("C", 120, 15)
        # show humidity
        oled.show_text("Humidity:", 0, 30)
        oled.show_text(str(int(humidity)), 75, 30)
        oled.show_text("%", 105, 30)

        # show oled
        oled.oled.show()
    # detect and read value, print “Failed to read from sensor:” if an error occurs
    except RuntimeError as e:
        print("Failed to read from sensor: ", e)
    time.sleep(1)	#delay 1S

Result:

After uploading code, you will see the values of temperature, humidity and air pressure on the OLED display.