from machine import Pin
import time

LED_PIN = 15                 # GP number: change to match your wiring
led = Pin(LED_PIN, Pin.OUT)  # set the pin as an output

while True:
    led.value(1)             # LED on
    time.sleep(0.5)          # wait half a second
    led.value(0)             # LED off
    time.sleep(0.5)          # wait half a second