import machine
import time

# define the GPIO pins for the traffic light LEDs
RED_LED_PIN = 1 # GP0 
YELLOW_LED_PIN = 5 # GP1
GREEN_LED_PIN = 9 # GP2

#Initialize the GPIO pins for the LEDs
 red_led = machine.Pin(RED_LED_PIN, machine.Pin.OUT)
 yellow_led = machine.pin(YELLOW_LED_PIN, machine.Pin.OUT)
 green_led = machine.Pin(GREEN_LED_PIN, machine.Pin.OUT)

# Function to turn on the specified LED and turn off the others
def turn_on_led(led_pin):
 red_led.value(led_pin == RED_LED_PIN)
 yellow_led.value(led_pin == YELLOW_LED_PIN)
 green_led.value(led_pin == GREEN_LED_PIN)

# Traffic light sequence
while True:
 # Red light
 turn_on_led(RED_LED_PIN)
 time.sleep(5)  # Red light for 5 seconds

# Red and yellow light (transition)
 turn_on_led(YELLOW_LED_PIN)
 time.sleep(2)  # Red and yellow lights for 5 seconds

# Red light
 turn_on_led(GREEN_LED_PIN)
 time.sleep(5)  # Green light for 5 seconds

# Red light
 turn_on_led(YELLOW_LED_PIN)
 time.sleep(2)  # Yellow light for 2 seconds