from machine import Pin
import time

# Define the GPIO pins for each LED
red_pin = Pin(0, Pin.OUT)    # GPIO 0
yellow_pin = Pin(2, Pin.OUT) # GPIO 2
green_pin = Pin(4, Pin.OUT)  # GPIO 4

# Function to switch off all LEDs
def all_off():
    red_pin.off()
    yellow_pin.off()
    green_pin.off()

# Function to display red light
def red_light():
    all_off()
    red_pin.on()

# Function to display yellow light
def yellow_light():
    all_off()
    yellow_pin.on()

# Function to display green light
def green_light():
    all_off()
    green_pin.on()

# Main program loop
while True:
    # Red light for 5 seconds
    red_light()
    time.sleep(5)
    
    # Yellow light for 2 seconds
    yellow_light()
    time.sleep(2)
    
    # Green light for 5 seconds
    green_light()
    time.sleep(5)