019 - ESP32 MicroPython: OpenWeather | RESTful APIs

Nov 20, 2020 · 4 min read · http get micropython micropython esp32 tutorials open weather openweather micropython openweather rest api openweather restful api ·

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Introduction

In the previous tutorial, I demonstrate using the RESTful APIs to communicate with Thingspeak server sending DHT sensor data. Now in this aticle, I will demonstrate the opposite which is requesting data from a server. This time, communicating with another server which is the OpenWeather. The receive data will be displayed on the OLED display.

We will use urequests MicroPython library to simplify our code for every HTTP request.

Bill Of Materials

ESP32 development board or any microcontroller with MicroPython firmware.
0.96 OLED display.

Hardware Instruction

Connect the OLED VCC pin to ESP32 3.3V pin.
Connect the OLED GND pin to ESP32 GND pin.
Connect the OLED SCL pin to ESP32 pin 22.
Connect the OLED SDA pin to ESP32 pin 21.
Save ssd1306.py to ESP32 MicroPython root directory. Refer to tutorial #10 for more details.
Copy and paste the source code provided below and save to your computer. Or you might want to save it to ESP32 MicroPython root directory with a name of main.py in order to run it automatically after reset.
Enjoy.

Video Demonstration

Call To Action

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See you,

– George Bantique | tech.to.tinker@gmail.com

Source Code

  1# **************************************# 
  2# Author: George Bantique               #  
  3#         TechToTinker Youtube Channel  # 
  4#         TechToTinker.blogspot.com     # 
  5#         tech.to.tinker@gmail.com      # 
  6# Date: Nov.20, 2020                    # 
  7# Please feel free to modify the code   # 
  8# according to your needs.              # 
  9# **************************************# 
 10
 11# ************************************** 
 12# Load necessary libraries 
 13import machine 
 14import ssd1306
 15import network  
 16import urequests
 17import ujson as json
 18import time 
 19
 20# ************************************** 
 21# Create objects: 
 22led = machine.Pin(2,machine.Pin.OUT)
 23
 24scl = machine.Pin(22, machine.Pin.OUT, machine.Pin.PULL_UP)
 25sda = machine.Pin(21, machine.Pin.OUT, machine.Pin.PULL_UP)
 26i2c = machine.I2C(scl=scl, sda=sda, freq=400000)
 27oled = ssd1306.SSD1306_I2C(128, 64, i2c, addr=0x3C)
 28def print_text(msg, x, y, clr):
 29    if clr:
 30        oled.fill(0)
 31    oled.text(msg, x, y)
 32    oled.show()
 33
 34# ************************************** 
 35# Configure the ESP32 wifi as STAtion 
 36sta = network.WLAN(network.STA_IF) 
 37if not sta.isconnected():  
 38  print('connecting to network...')  
 39  sta.active(True)  
 40  #sta.connect('your wifi ssid', 'your wifi password')  
 41  sta.connect('your wifi ssid', 'your wifi password')  
 42  while not sta.isconnected(): 
 43    pass  
 44print('network config:', sta.ifconfig()) 
 45
 46# **************************************
 47# Global variables and constants:
 48#api.openweathermap.org/data/2.5/weather?q={city name}&appid={API key}
 49#https://api.openweathermap.org/data/2.5/weather?q=manila&appid=3c2034495c602ddfa627774642a672b0
 50
 51BASE_URL = "https://api.openweathermap.org/data/2.5/weather?"
 52API_KEY = "your api key" 
 53CITY_NAME = "your city here" 
 54URL = BASE_URL + "q=" + CITY_NAME + "&appid=" + API_KEY
 55
 56UPDATE_INTERVAL_ms = 5000 # in ms time unit
 57last_update = time.ticks_ms()
 58
 59# **************************************
 60# Main loop:
 61while True:
 62    if time.ticks_ms() - last_update >= UPDATE_INTERVAL_m
 63        # send a weather data request
 64        response = urequests.get(URL)
 65
 66        # check status code of the request 
 67        if response.status_code == 200: 
 68            # get the json format of data
 69            data = response.json() 
 70
 71            # get the main dict block
 72            # it contains the weather data
 73            main = data['main'] 
 74
 75            # get the temperature and subtract
 76            # 273.15 to get temp in Celcius
 77            # originally temp is in Kelvin
 78            temperature = main['temp'] - 273.15 
 79
 80            # get the humidity in %
 81            humidity = main['humidity'] 
 82
 83            # get the pressure in hPA
 84            pressure = main['pressure'] 
 85
 86            # weather report 
 87            report = data['weather'] 
 88
 89            ## OLED display
 90            print_text('**OpenWeather**', 3, 5, 1)
 91            print_text('City:{}' .format(CITY_NAME), 3, 15, 0)
 92            print_text('Temp:{} oC' .format(temperature), 3, 25, 0)
 93            print_text('Humi:{} %' .format(humidity), 3, 35, 0)
 94            print_text('Pres:{} hPa' .format(pressure), 3, 45, 0)
 95            print_text('"{}."' .format(report[0]['description']), 3, 55, 0)
 96
 97            ## debug messages
 98            print('')
 99            print('**OpenWeather**')
100            print('City:{}' .format(CITY_NAME))
101            print('Temperature:{} oC' .format(temperature)) 
102            print('Humidity:{} %' .format(humidity)) 
103            print('Pressure:{} hPa' .format(pressure)) 
104            print('Weather Report:{}.' .format(report[0]['description'])) 
105        else: 
106            # show error message 
107            print_text('Error in HTTP request.', 3, 20, 1)
108            print('Error in HTTP request.')
109
110        led.value(not led.value())
111        last_update = time.ticks_ms()