bouton-gpio.py
A button on the GPIO header triggers an action on press and release. Generic version that polls the gpiod line directly, with a 30 ms software debounce filter.
Hardware required
A BeagleBone AI-64 (TI J721E, 2 GHz) on the official Debian image, powered by 5 V/4 A USB-C, with its two 3.3 V P8/P9 cape headers. 1 push button (one leg to the GPIO pin, the other to GND).
Wiring
Button between the chosen GPIO and GND; enable the internal pull via the gpiod flag if the circuit has no resistor.
How it works
The pin level is watched; a valid edge (stable for 30 ms) runs the action. gpiozero delegates everything to asynchronous callbacks. On Debian: sudo apt install gpiod python3-gpiod; gpiodetect lists the chips (main one is 600000.gpio). The P8/P9 pins are named in gpioinfo.
Going further
Press counter, double-click (interval measurement), or triggering a shell script via subprocess.
bouton-gpio.py
#!/usr/bin/env python3
# Bouton poussoir avec python3-gpiod : scrutation + anti-rebond.
import gpiod
from time import sleep
PUCE = "gpiochip1" # verifier avec gpiodetect
LIGNE = 16 # GPIO du bouton (schema de la carte)
chip = gpiod.Chip(PUCE)
line = chip.get_line(LIGNE)
line.request(consumer="bouton", type=gpiod.LINE_REQ_DIR_IN,
default_val=gpiod.LINE_REQ_FLAG_NONE)
print("Scrutation du bouton (Ctrl-C pour quitter)")
precedent = line.get_value()
try:
while True:
etat = line.get_value()
if etat != precedent:
sleep(0.03) # anti-rebond 30 ms
etat = line.get_value()
if etat != precedent:
print("Bouton:", "APPUIE" if etat else "relache")
precedent = etat
sleep(0.01)
finally:
line.release()