In this article, we will explore the Flask framework and its relevance in the Raspberry Pi environment. Flask is a lightweight web framework written in Python that allows developers to easily build web applications. Its simplicity and versatility make it an ideal choice for Raspberry Pi projects, where resources and performance are often limited. By using Flask on Raspberry Pi, developers can create interactive web interfaces to control and monitor their projects, making them more accessible and user-friendly.

Examples:

1. Installing Flask on Raspberry Pi: To install Flask on Raspberry Pi, open a terminal and run the following commands:

sudo apt update
sudo apt install python3-pip
pip3 install flask

2. Creating a Simple Web Application: Create a new Python file called app.py and add the following code:

from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello():
    return "Hello, Raspberry Pi!"

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0')

Save the file and run it using the following command:

python3 app.py

Open a web browser and navigate to http://localhost:5000 to see the "Hello, Raspberry Pi!" message.

3. Adding GPIO Control to the Web Application: To control GPIO pins on Raspberry Pi through the web application, we need to install the RPi.GPIO library. Run the following commands to install it:

sudo apt install python3-rpi.gpio

Next, modify the app.py file to include GPIO control:

from flask import Flask
import RPi.GPIO as GPIO

app = Flask(__name__)

GPIO.setmode(GPIO.BOARD)
GPIO.setup(11, GPIO.OUT)

@app.route('/')
def hello():
    return "Hello, Raspberry Pi!"

@app.route('/toggle')
def toggle():
    GPIO.output(11, not GPIO.input(11))
    return "GPIO 11 toggled!"

if __name__ == '__main__':
    app.run(debug=True, host='0.0.0.0')

Now, when you navigate to http://localhost:5000/toggle, it will toggle the state of GPIO pin 11.