import time
import machine
import random
import time
from machine import Pin, Timer

led = Pin(1, Pin.OUT)
timer = Timer()

def blink_led(timer):
    led.on()
    time.sleep(0.5)
    led.off()
    time.sleep(0.5)

timer.init(freq=2, mode = Timer.PERIODIC, callback = blink_led)
time.sleep()
led.off()
timer.deinit()