#define echo 3 // echo pin
#define trigg 5 //trig pin
float duration;
float distance;

void setup() {
  // put your setup code here, to run once:
pinMode(trigg, OUTPUT);
pinMode(echo, INPUT);
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
time_measure();
distance=(float)duration*(0.0343)/2;
Serial.println(distance);

}
void time_measure()
{
  digitalWrite(trigg, LOW);
  delay(500);
  digitalWrite(trigg, HIGH);
  delay(500);
  digitalWrite(trigg, LOW);
  duration=pulseIn(echo, HIGH);
}