Pi Zero GPIO Basics: LED and Push Button in Python with gpiozero

#!/usr/bin/env python3
"""LED and button demo for Raspberry Pi Zero using gpiozero.

Short press : toggle the LED on/off
Hold 2 s    : blink the LED rapidly
"""
from signal import pause
from gpiozero import LED, Button

led = LED(17)                      # BCM GPIO17, physical pin 11
button = Button(27, hold_time=2,   # BCM GPIO27, physical pin 13
                bounce_time=0.05)  # 50 ms software debounce

held = False  # remembers whether the last press was a long press

def on_press():
    global held
    held = False  # new press, not held yet

def on_release():
    # Only toggle on a short press; a long press is handled in on_hold
    if not held:
        led.toggle()
        print('LED is now', 'ON' if led.is_lit else 'OFF')

def on_hold():
    global held
    held = True
    print('Long press: blinking')
    # Runs in a background thread; returns immediately
    led.blink(on_time=0.1, off_time=0.1, n=10)

button.when_pressed = on_press
button.when_released = on_release
button.when_held = on_hold

print('Ready. Press the button (Ctrl+C to quit).')
pause()  # keep the script alive; callbacks run in the background

#!/usr/bin/env python3
"""Fade an LED using PWM. The LED breathes only while the button is held."""
from signal import pause
from gpiozero import PWMLED, Button

led = PWMLED(17, frequency=200)  # 200 Hz avoids visible flicker
button = Button(27)

def start_breathing():
    # fade_in_time/fade_out_time in seconds; background=True returns at once
    led.pulse(fade_in_time=1, fade_out_time=1, background=True)

def stop_breathing():
    led.off()

button.when_pressed = start_breathing
button.when_released = stop_breathing

# You can also set brightness directly from 0.0 to 1.0, e.g. led.value = 0.3
pause()