from machine import Pin, PWM
import utime
trigger = Pin(3, Pin.OUT)
echo = Pin(2, Pin.IN)
buzzer = PWM(Pin(15))
distance=0
def ultra():
   trigger.low()
   utime.sleep_us(2)
   trigger.high()
   utime.sleep_us(5)
   trigger.low()
   while echo.value() == 0:
       signaloff = utime.ticks_us()
   while echo.value() == 1:
       signalon = utime.ticks_us()
   timepassed = signalon - signaloff
   distance = (timepassed * 0.0343) / 2
   #print("The distance from object is ",distance,"cm")
   if (distance < 200):
    print("The distance from object is ",distance,"cm")
    buzzer.freq(500)
    buzzer.duty_u16(1000)
   else:
    buzzer.freq(200)
    buzzer.duty_u16(1000)
    utime.sleep(1)
    
while True:
   ultra()