Update tech_docs/python/Python_programming.md

tech_docs/python/Python_programming.md

@@ -184,6 +184,144 @@ Understanding where data comes from and how to handle it is crucial for developi
 
 ---
 
+Sure, let's break down the code snippet and understand how and where each of the imported libraries is used:
+
+### 1. `import machine`
+
+The `machine` module is used to interact with the hardware of the microcontroller. It provides functions to control pins, I2C, SPI, etc.
+
+**Usage in the code:**
+- `machine.Pin(4)`: This line creates a pin object for GPIO pin 4, which is used to interface with the DHT22 sensor.
+
+```python
+sensor = dht.DHT22(machine.Pin(4))
+```
+
+### 2. `import dht`
+
+The `dht` module is specifically for interacting with DHT sensors (DHT11, DHT22). It provides methods to initialize the sensor and read temperature and humidity data.
+
+**Usage in the code:**
+- `dht.DHT22(machine.Pin(4))`: Initializes the DHT22 sensor on pin 4.
+- `sensor.measure()`: Triggers the sensor to take a measurement.
+- `sensor.temperature()`: Retrieves the temperature reading.
+- `sensor.humidity()`: Retrieves the humidity reading.
+
+```python
+sensor = dht.DHT22(machine.Pin(4))
+
+def read_sensor_data():
+    sensor.measure()
+    temp = sensor.temperature()
+    humidity = sensor.humidity()
+    return temp, humidity
+```
+
+### 3. `import time`
+
+The `time` module provides various time-related functions. It is commonly used for adding delays and getting the current time.
+
+**Usage in the code:**
+- `time.sleep(1)`: Pauses the execution for 1 second (used while waiting for the Wi-Fi connection).
+- `time.sleep(60)`: Pauses the execution for 60 seconds in the main loop to wait before reading the sensor data again.
+
+```python
+while not wifi.isconnected():
+    time.sleep(1)
+
+while True:
+    temperature, humidity = read_sensor_data()
+    print(f'Temperature: {temperature}C, Humidity: {humidity}%')
+    send_data(temperature, humidity)
+    time.sleep(60)  # Wait for 60 seconds before reading again
+```
+
+### 4. `import network`
+
+The `network` module provides functions to configure and control the network interfaces. It is used for connecting the microcontroller to a Wi-Fi network.
+
+**Usage in the code:**
+- `network.WLAN(network.STA_IF)`: Initializes the Wi-Fi interface in station mode.
+- `wifi.active(True)`: Activates the Wi-Fi interface.
+- `wifi.connect('your_ssid', 'your_password')`: Connects to the specified Wi-Fi network.
+- `wifi.isconnected()`: Checks if the microcontroller is connected to the Wi-Fi network.
+
+```python
+wifi = network.WLAN(network.STA_IF)
+wifi.active(True)
+wifi.connect('your_ssid', 'your_password')
+
+while not wifi.isconnected():
+    time.sleep(1)
+```
+
+### 5. `import urequests`
+
+The `urequests` module is a simplified version of the `requests` library, used to make HTTP requests from microcontrollers. It is used to send data to a server.
+
+**Usage in the code:**
+- `urequests.post(url, json=data, headers=headers)`: Sends an HTTP POST request to the specified URL with the sensor data in JSON format.
+
+```python
+def send_data(temp, humidity):
+    url = 'http://your_server_endpoint'
+    data = {'temperature': temp, 'humidity': humidity}
+    headers = {'Content-Type': 'application/json'}
+    response = urequests.post(url, json=data, headers=headers)
+    print(response.text)
+```
+
+### Complete Code Snippet with Comments
+
+```python
+# Import necessary libraries
+import machine  # Interacts with the microcontroller's hardware (pins, I2C, etc.)
+import dht      # Interacts with DHT sensors to read temperature and humidity
+import time     # Provides time-related functions (delays, etc.)
+import network  # Manages network connections (Wi-Fi)
+import urequests # Simplified HTTP requests library for microcontrollers
+
+# Set up Wi-Fi connection
+wifi = network.WLAN(network.STA_IF)  # Initialize Wi-Fi in station mode
+wifi.active(True)  # Activate Wi-Fi interface
+wifi.connect('your_ssid', 'your_password')  # Connect to Wi-Fi network
+
+# Wait for Wi-Fi connection
+while not wifi.isconnected():
+    time.sleep(1)
+
+print("Connected to Wi-Fi")
+
+# Set up the sensor
+sensor = dht.DHT22(machine.Pin(4))  # Initialize DHT22 sensor on GPIO pin 4
+
+# Function to read sensor data
+def read_sensor_data():
+    sensor.measure()  # Trigger measurement
+    temp = sensor.temperature()  # Get temperature reading
+    humidity = sensor.humidity()  # Get humidity reading
+    return temp, humidity
+
+# Function to send data to a server
+def send_data(temp, humidity):
+    url = 'http://your_server_endpoint'
+    data = {'temperature': temp, 'humidity': humidity}
+    headers = {'Content-Type': 'application/json'}
+    response = urequests.post(url, json=data, headers=headers)  # Send POST request
+    print(response.text)
+
+# Main loop
+while True:
+    temperature, humidity = read_sensor_data()  # Read sensor data
+    print(f'Temperature: {temperature}C, Humidity: {humidity}%')
+    send_data(temperature, humidity)  # Send data to server
+    time.sleep(60)  # Wait for 60 seconds before reading again
+```
+
+This code snippet demonstrates a complete IoT application where a microcontroller reads data from a DHT22 sensor, connects to a Wi-Fi network, and sends the sensor data to a server at regular intervals. Each import plays a specific role in the operation of the application, from hardware interaction to network communication and data transmission.
+
+---
+
 Object-oriented programming (OOP) is a paradigm that organizes software design around data, or objects, rather than functions and logic. The key concepts of OOP are encapsulation, abstraction, inheritance, and polymorphism. Understanding how to relate OOP to real-world problems involves thinking about the entities involved as objects with properties (attributes) and behaviors (methods). Here’s a guide to help you understand and apply OOP principles effectively.
 
 ### Key Concepts of OOP