from machine import Pin, PWM
from time import sleep_ms

buzzer = PWM(Pin(20))
buttons = [Pin(i, Pin.IN, Pin.PULL_UP) for i in [11,12,13,14,15]]

def play_note(freq, duration=20):
    buzzer.freq(freq)
    buzzer.duty_u16(32768)
    sleep_ms(duration)
    buzzer.deinit()

while True:
    for i, btn in enumerate(buttons):
        if btn.value()==0:
            play_note(260+i*80)