import time
import machine
time.sleep(0.1) # Wait for USB to become ready

red_light = machine.Pin(0,machine.Pin.OUT)
yellow_light = machine.Pin(9, machine.Pin.OUT)
green_light = machine.Pin(15, machine.Pin.OUT)
button = machine.Pin(16,machine.Pin.IN, machine.Pin.PULL_UP)
buzzer = machine.Pin(28, machine.Pin.OUT)

button_pressed = False
def button_handler(pin):
    global button_pressed
    if not button_pressed:
        button_pressed = True

button.irq(trigger=machine.Pin.IRQ_FALLING, handler=button_handler)

while True:
    if button_pressed == True:
        red_light.value(1)
        for i in range(20):
            buzzer.value(1)
            print("go crossing")
            time.sleep(0.05)
            buzzer.value(0)
            time.sleep(0.5)
        button_pressed == False
    red_light.value(1)
    time.sleep(5)
    red_light.value(0)
    yellow_light.value(1)
    time.sleep(3)
    yellow_light.value(0)
    green_light.value(1)
    time.sleep(5)