🛠 Lire un bouton et afficher dans la console

Objectives

Configure a pin on the 40-pin connector as an input with internal pull-up, read a push button in Python using libgpiod, and display each press in the console. This is the basis for any physical interaction with the ODROID-M1.

Hardware

• ODROID-M1 running Armbian (python3-gpiod package)
• 1 push button (no external resistor required: internal pull-up)
• >

Complete Code

#!/usr/bin/env python3
"""Compteur d'appuis sur bouton, libgpiod (chip/ligne à adapter)."""
import time
from gpiod import chip, line

CHIP, LIGNE = "gpiochip1", 22  # exemple banque gpio1 du RK3568B2
compteur = 0
with chip(CHIP) as g:
    g.request_lines(consumer="bouton", config={
        LIGNE: line.RequestConfig(
            line=LIGNE, consumer="bouton",
            request_type=line.RequestType.INPUT,
            bias=line.Bias.PULL_UP),
    })
    print("En attente d'appuis (Ctrl-C pour quitter)...", flush=True)
    while True:
        if g.get_value(LIGNE) == 0:      # bouton fermé vers la masse
            compteur += 1
            print(f"Appui n°{compteur}", flush=True)
            time.sleep(0.3)              # anti-rebond logiciel
        time.sleep(0.05)

Expected Verification

Each press displays "Press n°X" in the console; releasing the button generates nothing thanks to the internal pull-up.

Common Errors

• Forgetting the pull-up: the input floats and displays phantom presses.
• Wiring the button to 3.3 V instead of ground with pull-up: inverted logic.
• Debounce time too short: a single physical press counts multiple times.
• Line already claimed by another program: libgpiod refuses the request, you must free the other process.