Python For Microcontroller, Raspberry Pi

Read and Display Environment Sensor Data Using Raspberry Pi Pico and CircuitPython

by Idris
February 23, 2021

BMP280, CircuitPython, Raspberry Pi Pico, SHT30, SSD1306

Read environment sensor data and display it to OLED using Maker Pi Pico and CircuitPython.

Introduction

In this tutorial, we will try to read sensor data from M5Stack Environment Sensor Unit II and display it to the OLED Grove module using I2C communication. The advantage of using I2C is we can use a single bus (SDA, SCL) to communicate with multiple devices with different addresses. However, for this tutorial we would like to test on different I2C ports for sensors and display.

Video

This video shows how to read environment sensor data and display it to OLED using Maker Pi Pico and CircuitPython.

Hardware Preparation

This is the list of items used in the video.

Maker Pi Pico

USB Micro B Cable

M5Stack Environment Sensor Unit II

Grove – OLED Display 0.96 inch

Sample Program

This is CircuitPython sample program to read environment sensor data and display it to OLED through I2C communication using Maker Pi Pico and CircuitPython. Please include those CircuitPython libraries in the Raspberry Pi Pico CIRCUITPY drive.

adafruit_bus_device
adafruit_display_text
adafruit_bmp280.mpy
adafruit_displayio_ssd1306.mpy
adafruit_sht31d.mpy

    # 
  # Read and display evironment sensor data using Raspberry Pi Pico and CircuitPython 
  # 
  # References and credit to 
  # – https://learn.adafruit.com/monochrome-oled-breakouts/circuitpython-usage 
  # – https://learn.adafruit.com/adafruit-bmp280-barometric-pressure-plus-temperature-sensor-breakout/circuitpython-test 
  # – https://learn.adafruit.com/adafruit-sht31-d-temperature-and-humidity-sensor-breakout/python-circuitpython 
  # 
  # Raspberry Pi Pico 
  # – [Maker Pi Pico] https://my.cytron.io/p-maker-pi-pico?tracking=idris 
  # Grove – OLED Display 0.96 inch 
  # – https://my.cytron.io/p-grove-oled-display-0p96-inch-ssd1315 
  # M5Stack Environment Sensor Unit II 
  # – https://my.cytron.io/p-m5stack-environment-sensor-unit-ii 
  # 
  # Additional Libraries 
  # – adafruit_bus_device 
  # – adafruit_display_text 
  # – adafruit_bmp280.mpy 
  # – adafruit_displayio_ssd1306.mpy 
  # – adafruit_sht31d.mpy 
  # 
  # Update: 
  # 21 Feb 2021 – Tested with CircuitPython Pico 6.2.0-beta.2 
  # 
    
  import time 
  import board 
  import busio 
  import displayio 
  import terminalio 
  from adafruit_display_text import label 
  import adafruit_displayio_ssd1306 
  import adafruit_bmp280 
  import adafruit_sht31d 
    
  displayio.release_displays() 
    
  i2c_oled = busio.I2C(scl=board.GP5, sda=board.GP4) 
  display_bus = displayio.I2CDisplay(i2c_oled, device_address=0x3C) 
  display = adafruit_displayio_ssd1306.SSD1306(display_bus, width=128, height=64) 
    
  i2c_sensor = busio.I2C(scl=board.GP3, sda=board.GP2) 
  bmp280 = adafruit_bmp280.Adafruit_BMP280_I2C(i2c_sensor, address=0x76) 
  sht30 = adafruit_sht31d.SHT31D(i2c_sensor, address=0x44) 
    
  while True: 
   print("\nTemperature: {:.2f} C".format(sht30.temperature)) 
   print("Humidity: {:.2f} %".format(sht30.relative_humidity)) 
   print("Pressure: {:.2f} hPa".format(bmp280.pressure)) 
   print("Altitude = {:.2f} meters".format(bmp280.altitude)) 
    
   # Make the display context 
   text_group = displayio.Group(max_size=10) 
    
   # Draw a label 
   text = "ENVIRONMENT SENSOR" 
   text_area = label.Label(terminalio.FONT, text=text, color=0xFFFFFF, x=0, y=4) 
   text_group.append(text_area) 
    
   text = "Temp (C): {:.2f}".format(sht30.temperature) 
   text_area = label.Label(terminalio.FONT, text=text, color=0xFFFFFF, x=0, y=17) 
   text_group.append(text_area) 
    
   text = "Humi (%): {:.2f}".format(sht30.relative_humidity) 
   text_area = label.Label(terminalio.FONT, text=text, color=0xFFFFFF, x=0, y=30) 
   text_group.append(text_area) 
    
   text = "Pres (hPa): {:.2f}".format(bmp280.pressure) 
   text_area = label.Label(terminalio.FONT, text=text, color=0xFFFFFF, x=0, y=43) 
   text_group.append(text_area) 
    
   text = "Alti (m): {:.2f}".format(bmp280.altitude) 
   text_area = label.Label(terminalio.FONT, text=text, color=0xFFFFFF, x=0, y=56) 
   text_group.append(text_area) 
    
   display.show(text_group) 
    
   time.sleep(2) 