from machine import Pin,PWM
import time

pwn_led = PWM(Pin(15))

pwn_led.freq(1000)

print("Breathing LED")

while True:

    for brightness in range(0,65536,1000):
        pwn_led.duty_u16(brightness)
        time.sleep(.02)
    for brightness in range(65535,-1,-1000):
        pwn_led.duty_u16(brightness)
        time.sleep(.02)