int echo = 9;
int trig = 8;
float time;
float act;
float dist;
float speed = 330;


void setup() {
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  Serial.begin(9600);


}

void loop() {
  digitalWrite(trig, HIGH);
  delayMicroseconds(1);


  digitalWrite(trig, LOW);
  delayMicroseconds(1);


  digitalWrite(trig, HIGH);

  time = pulseIn(echo, HIGH);
  act = time / 2;
  dist = 0.0342 * act;

  Serial.print(dist); Serial.println("cm");
  delay(500);


}