from machine import Pin, PWM
from time import sleep

buzzer = PWM(Pin(32,Pin.OUT))

def buzz(freq,masa):
    buzzer.freq(freq)
    buzzer.duty(50) 
    sleep(masa)           

while (True):
    buzz(300,0.2)
    buzz(350,0.2)
    buzz(400,0.2)
    buzz(1,0.2)