from machine import Pin,Timer
from time import sleep

pin_LED=Pin(15,Pin.OUT)

myTimer=Timer(1)

def toggle_led(myTimer):
    pin_LED.on()
    sleep(0.5)
    pin_LED.off()
    sleep(0.5)

myTimer.init(period=1000, mode=Timer.ONE_SHOT, callback=toggle_led)

while True:
    sleep(10)
    print("just sleep")