led_blink.py
The classic first GPIO build: an LED with a 330-ohm resistor blinks once per second via gpiozero. The script imports LED, targets GPIO17 (pin 11) and toggles it in a loop. Ideal to check the power supply (modèle A sans Ethernet : alimentation 5 V/700 mA via l'OTG, hub USB alimenté pour les périphériques) before a bigger project.
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). One red LED, a 330-ohm resistor, dupont wires (26-pin header).
Wiring
LED anode (long leg) to GPIO17 through the resistor, cathode to any GND pin of the P1 connector.
How it works
gpiozero sets the pin as output; led.on/off drive it to 3.3 V or 0 V. KeyboardInterrupt cleans up on exit.
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
Use led.blink(0.2, 0.8) for an asymmetric pattern; chain several LEDs for a scroller. Power through the OTG port at 5 V/700 mA minimum; avoid power-hungry USB devices.
led_blink.py
# led_blink.py — fait clignoter une LED via gpiozero.
# Deps: sudo apt install python3-gpiozero
# Montage : LED + resistance 330 ohms sur GPIO17 (broche 11), GND sur GND.
from gpiozero import LED
from time import sleep
LED_PIN = 17 # numero GPIO, pas numero de broche
ON_TIME = 0.5
OFF_TIME = 0.5
led = LED(LED_PIN)
print(f"Clignotement GPIO{LED_PIN}, Ctrl+C pour terminer")
try:
while True:
led.on()
sleep(ON_TIME)
led.off()
sleep(OFF_TIME)
except KeyboardInterrupt:
print("Arret propre")
led.off()