const int echo = 3;
const int tring = 4;
void setup() {
  Serial.begin(9600);
  pinMode(tring, OUTPUT);
  pinMode(echo, INPUT);

}
void loop() {
  digitalWrite(tring, HIGH);
  delayMicroseconds(10);
  digitalWrite(tring, LOW);

  int   tempo = pulseIn(echo, HIGH);
  int   dist = tempo*0.0172;
  Serial.println(dist);
  delay(1000);

}