import machine
import time
# Define the GPIO pins for the traffic light LEDs
RED_LED_PIN=1 #GP4
YELLOW_LED_PIN=5 #GP3
GREEN_LED_PIN=9 #GP2

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

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

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