web_led.py
A minimal Flask server exposes /on and /off to drive an LED on GPIO17 from any LAN browser. Without built-in Wi-Fi, connect over Ethernet/USB dongle: modèle A sans Ethernet : alimentation 5 V/700 mA via l'OTG, hub USB alimenté pour les périphériques. It listens on 0.0.0.0:8000; never expose the board to the Internet.
Hardware
A Raspberry Pi Model A (BCM2835, 26-pin GPIO header, a single OTG-mode USB port, no Ethernet: plan for a powered USB hub). LED + 330-ohm resistor, local network (Ethernet, Wi-Fi or USB dongle per model).
Wiring
LED on GPIO17 (pin 11) with resistor to GND. Nothing else but networking.
How it works
Each URL is a Flask route: the view calls led.on/off then re-renders with led.value. The single-thread server is fine for a demo.
Running it
Copy the script to the board (scp or USB stick), then run it with python3 (or bash). On older Raspbian, install gpiozero with sudo apt install python3-gpiozero. Power the board at 5 V/700 mA minimum through the OTG port.
Variants
Radio buttons for several GPIOs; systemd unit as a service; add flask-login before any network exposure. Power through the OTG port at 5 V/700 mA minimum; avoid power-hungry USB devices.
web_led.py
# web_led.py — page web locale pour allumer/eteindre une LED (Flask).
# Deps: sudo apt install python3-flask python3-gpiozero
from flask import Flask
from gpiozero import LED
app = Flask(__name__)
led = LED(17)
@app.route("/")
def index():
etat = "allumee" if led.value else "eteinte"
return (f"<h1>LED {etat}</h1>"
'<p><a href="/on">Allumer</a> | <a href="/off">Eteindre</a></p>')
@app.route("/on")
def on():
led.on()
return index()
@app.route("/off")
def off():
led.off()
return index()
if __name__ == "__main__":
app.run(host="0.0.0.0", port=8000)