from machine import Pin, PWM
from time import sleep,sleep_us

trigger = Pin(26, Pin.OUT)
echo = Pin(22, Pin.IN)
buzz=Pin(5,Pin.OUT)

def get_distance():
    trigger.on()
    sleep_us(10)
    trigger.off()
    duration = machine.time_pulse_us(echo, 1, 30000)
    distance = duration * 0.0343 / 2
    return distance

while True:
    temp=get_distance()
    if temp<=50:
        print('obstacle ahead')
        buzz.on()
        sleep_us(1000)
        buzz.off()
    else:
        print('no obstacle found')
        buzz.off()
        sleep_us(1000)