from machine import Pin, PWM
from time import sleep

servo = PWM(Pin(17), freq=50, duty_ns=1450000)
sleep(3)
while True:
  for d in range(1450000, 400000, -100000):
    servo.duty_ns(d)
    sleep(0.1)
  sleep(1)
  for d in range (400000, 2500000, 100000):
    servo.duty_ns(d)
    sleep(0.1)
  sleep(1)
  servo.deinit()
  sleep(1)
  servo.init(freq=50, duty_ns=1450000)
  sleep(3)