Workwi Simulator Environment Setup

Navigate to Wokwi ESP32 MicroPython Project.
Start a new project and choose ESP32 as your microcontroller.
Wokwi simulates a Wi-Fi network that you can use to prototype IoT projects.

Understanding the Code

We'll write a simple MicroPython script to connect to a simulated Wi-Fi network named 'Wokwi-GUEST'.

Here's a breakdown of the code Connecting from MicroPython:

Import libraries: network for networking functionality, and time for pausing the script.
Print a message to the console to indicate the Wi-Fi connection process is starting.
Create a WLAN (Wireless Local Area Network) object to interact with the Wi-Fi settings.
Activate the WLAN interface.
Attempt to connect to the 'Wokwi-GUEST' Wi-Fi network.
Wait until the connection is established before proceeding.
Print a message to the console to indicate the Wi-Fi connection is successful.

Writing MicroPython Code

Type the following MicroPython code directly into the Wokwi editor:

import network
import time

print("Connecting to WiFi", end="")
sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect('Wokwi-GUEST', '')
while not sta_if.isconnected():
    print(".", end="")
    time.sleep(0.1)
print(" Connected!")

Workwi WiFi Connect

Accessing Web Page Data

Once connected to Wi-Fi, you can access web pages and retrieve data.

Here is a simple example using the `urequests` library to send an HTTP GET request to a webpage:

import requests

# URL of the CSV file
url = "https://data.moenv.gov.tw/api/v2/aqx_p_432?\
api_key=e8dd42e6-9b8b-43f8-991e-b3dee723a52d&format=CSV"

# Send an HTTP GET request to the URL
response = requests.get(url)

# Check if the request was successful (status code 200)
if response.status_code == 200:
    # Get the content of the response
    response_text = response.text
    
    # Print the content of the CSV data
    print(response_text)
    
else:
    print(f"Failed to download CSV data. Status code: {response.status_code}")

Accessing Web Page Data

Get AQI information

res = response_text.split("\n")

cols = res[2].split(',')
print(f"cols {cols}")
#print(cols.index('aqi'))
#get hualien data_type
for info in res:
    if '花蓮' in info:
        #print(info)
        print(info.split(',')[cols.index('aqi')])

https://colab.research.google.com/drive/1vplGqjSSyxE5yWMjj_MgCHJsCM7NcMHi?usp=sharing

WiFi AQI Information

Additional Resources

Explore Wokwi documentation for more details on ESP32 Wi-Fi networking and simulations: Wokwi ESP32 WiFi Networking Guide.
For advanced networking, like sending HTTP requests or establishing MQTT connections, learn about libraries like urequests and umqtt.

Conclusion

Now you've learned the basics of setting up a Wi-Fi connection on an ESP32 using MicroPython in Wokwi, and how to access web page data. Keep experimenting and happy coding!

RTC Module in MicroPython

The RTC module in MicroPython is used for real-time clock functionality.
It allows setting and retrieving the current date and time.
The datetime method can be used both to set and get the date and time.

RTC.datetime Method

The datetime method returns an 8-tuple when called without arguments.
The tuple format is:
(year, month, day, weekday, hours, minutes, seconds, subseconds).
subseconds is hardware-dependent.
To set the date and time, pass an 8-tuple to datetime.

RTC Module Example code

from machine import RTC
# Create an RTC object
rtc = RTC()
# Set the date and time
rtc.datetime((2017, 8, 23, 1, 12, 48, 0, 0))
# Retrieve the current date and time
current_datetime = rtc.datetime()
print(f"current_datetime : {current_datetime}")

Time Module in MicroPython

The time module provides functions to work with time.
localtime([secs]) converts time in seconds since the Epoch to an 8-tuple.
If secs is not provided, the current time is used.
gmtime() returns UTC time, while localtime() returns local time.

Time.localtime and gmtime Functions

The format of the 8-tuple is:
(year, month, mday, hour, minute, second, weekday, yearday).
year includes the century (e.g., 2014).
month is 1-12
mday is 1-31.
hour is 0-23; minute and second are 0-59.
weekday is 0-6 for Monday to Sunday
yearday is 1-366.

Time Example Code

import time

# Get the current time in seconds since the Epoch (Unix time)
current_time_seconds = time.time()

# Convert seconds since Epoch to a time tuple in local time
local_time_tuple = time.localtime(current_time_seconds)

# Format the time tuple into a human-readable date and time string
# The format is Year-Month-Day Hour:Minute:Second
formatted_time = "{:04d}-{:02d}-{:02d} {:02d}:{:02d}:{:02d}".format(
    local_time_tuple[0],  # Year
    local_time_tuple[1],  # Month
    local_time_tuple[2],  # Day
    local_time_tuple[3],  # Hour
    local_time_tuple[4],  # Minute
    local_time_tuple[5]   # Second
)

print("Current Local Time:", formatted_time)

ntptime Module in MicroPython

The ntptime module is used to synchronize the RTC with an NTP server.
This provides precise time, especially useful when the RTC is not accurate.
Use ntptime.settime() to update the RTC.

Download ntptime Module

Upload ntptime Module

import network, time, import ntptime

print("Connecting to WiFi", end="")
sta_if = network.WLAN(network.STA_IF)
sta_if.active(True)
sta_if.connect('Wokwi-GUEST', '')
while not sta_if.isconnected():
    print(".", end="")
    time.sleep(0.1)
print(" Connected!")

ntptime.host = 'tock.stdtime.gov.tw'
ntptime.timeout = 10
ntptime.settime()

# Convert seconds since Epoch to a time tuple in local time
local_time_tuple = time.localtime()
# Format the time tuple into a human-readable date and time string
# The format is Year-Month-Day Hour:Minute:Second
formatted_time = "{:04d}-{:02d}-{:02d} {:02d}:{:02d}:{:02d}".format(
    local_time_tuple[0],  # Year
    local_time_tuple[1],  # Month
    local_time_tuple[2],  # Day
    local_time_tuple[3],  # Hour
    local_time_tuple[4],  # Minute
    local_time_tuple[5]   # Second
)
print("Current Local Time:", formatted_time)

ntptime Example Code

ESP32 Networking Basics 🔗

ESP32 as an Access Point (AP)

Function:
Creates a standalone Wi-Fi network that other devices can join.
Use Cases:
Setting up a local network for IoT devices, workshops, or temporary setups.
Advantage:
Useful where no existing Wi-Fi network is available, or for creating an isolated network.

Initialization

import network, time
ap = network.WLAN(network.AP_IF) # Initializes the access point interface
ap.active(False) # Deactivates the first AP interface
time.sleep(0.1) # Waits for 0.1 seconds to ensure the interface is properly deactivated
ap.active(True) # Reactivates the first AP interface

Configuring the Access Point

ap.config(ssid='MyESP32AP') # Sets the SSID and password of the AP
print('AP IP:', ap.ifconfig()[0]) # Displays the IP address of the ESP32 in AP mode

ESP32 as a Wi-Fi Station (STA)

Function:
Connects ESP32 to an existing Wi-Fi network.
Use Cases:

Access the internet

interact with web services

communicate with other network devices.

Advantage:

Enables ESP32 to become part of a larger network, such as home automation.

Initialization

import network, time
wlan = network.WLAN(network.STA_IF) # Initializes the station interface
wlan.active(True) # Activates the WLAN interface
ssid = 'CSIE_C306'
passwd = '@ndhuc306'

Connecting to a Wi-Fi Network

connected = wlan.isconnected() # Check if the connection was successful
if not connected: # if it is not connected
    print(f'Trying to connect to {ssid}') # Display a message indicating an attempt to connect
    wlan.connect(ssid, passwd) # Attempt to connect to the Wi-Fi network again
    for _ in range(100): # Try to connect 100 times, waiting 0.1 seconds each time
        connected = wlan.isconnected() # Check if the connection was successful
        if connected:
           break # Break out of the loop if connected
        time.sleep(0.1) # Wait for 0.1 seconds before checking again
        print('.', end='') # Print progress dots to indicate ongoing connection attempts

if connected: # If connected successfully
    # Display successful connection and network configuration
    print(f'\nConnected to ssid {ssid}. Network config: {wlan.ifconfig()}') 
else: # If the connection failed
    print(f'\nFailed. Not Connected to: {ssid}') # Display a failure message

Access AQI Information

import urequests
# URL of the CSV file
url = "https://data.moenv.gov.tw/api/v2/aqx_p_432?\
api_key=e8dd42e6-9b8b-43f8-991e-b3dee723a52d&limit=1000&sort=ImportDate%20desc&format=CSV"

# Send an HTTP GET request to the URL
response = urequests.get(url)

# Check if the request was successful (status code 200)
if response.status_code == 200:
    # Get the content of the response
    response_text = response.text
    # Print the content of the CSV data
    print(response_text) 
else:
    print(f"Failed to download CSV data. Status code: {response.status_code}")

res = response_text.split("\n")
cols = res[2].split(',')
print(f"cols {cols}")
#print(cols.index('aqi'))
#get hualien data_type
for info in res:
    if '花蓮' in info:
        #print(info)
        aqi = info.split(',')[cols.index('aqi')]
        print(f"花蓮  AQI ： {aqi}")

Excercise

Show the AQI information to OLED

花蓮

AQI ： 19

ESP32 Wi-Fi

Introduction

Workwi Simulator Environment Setup

Understanding the Code

Writing MicroPython Code

Workwi WiFi Connect

Accessing Web Page Data

Accessing Web Page Data

Get AQI information

WiFi AQI Information

Additional Resources

Conclusion

RTC Module in MicroPython

RTC.datetime Method

RTC Module Example code

Time Module in MicroPython

Time.localtime and gmtime Functions

Time Example Code

ntptime Module in MicroPython

Download ntptime Module

Upload ntptime Module

ntptime Example Code

ESP32 Networking Basics 🔗

ESP32 as an Access Point (AP)

Initialization

Configuring the Access Point

ESP32 as a Wi-Fi Station (STA)

Initialization

Connecting to a Wi-Fi Network

Access AQI Information

Excercise

Show the AQI information to OLED