from machine import Pin, I2C
from utime import sleep

rojo = Pin(4, Pin.OUT)
verde = Pin(2, Pin.OUT)
amarillo = Pin(3, Pin.OUT)

B_rojo = Pin(20, Pin.IN, Pin.PULL_DOWN)
B_verde = Pin(22, Pin.IN, Pin.PULL_DOWN)
B_amarillo = Pin(21, Pin.IN, Pin.PULL_DOWN)

while True:
verde.value(0)
rojo.value(0)
amarillo.value(0)

if B_verde.value() == 1:
verde.value(1)
if B_rojo.value() == 1:
rojo.value(1)
if B_amarillo.value() == 1:
amarillo.value(1)
sleep(0.1)