traffic.py

# Traffic lights

from gpiozero import LED
from time import sleep

from gpiozero.pins.pigpio import PiGPIOFactory
factory = PiGPIOFactory(host='raspberrypi')

red_led = LED(17, pin_factory=factory)
yellow_led = LED(27, pin_factory=factory)
green_led = LED(22, pin_factory=factory)

def cycle():
    red_led.on()
    yellow_led.off()
    green_led.off()
    sleep(2)

    yellow_led.on()
    sleep(1)

    red_led.off()
    yellow_led.off()
    green_led.on()
    sleep(2)

    yellow_led.on()
    green_led.off()
    sleep(1)


while True:
    cycle()