import machine
from time import sleep_us,sleep
from machine import Pin, PWM
switch = Pin(14, Pin.IN)
buzzer=PWM(Pin(2),Pin.OUT)
freq=10
last_distance = ""
echo=Pin(33,Pin.IN)
trig=Pin(25,Pin.OUT)
while True:
    sw_state = switch.value()
    trig.value(0)
    sleep_us(2)
    trig.value(1)
    sleep_us(10)
    trig.value(0)
    x=machine.time_pulse_us(echo,1)
    distance=(0.034*x)/2  
    if sw_state == 1:
        if distance <= 20:
            buzzer.freq(2200)
            sleep(1)
        elif distance <= 50:
            buzzer.freq(1500)
            sleep(0.2)
            buzzer.freq(5)
            sleep(0.2)
        elif distance <= 100:
            buzzer.freq(1300)
            sleep(0.5)
            buzzer.freq(5)
            sleep(0.7)
        elif distance > 100:
            buzzer.freq(1)
            sleep(1)