const int echo=14;
const int trig=12;
float duration;
float distance;
void setup()
{
  Serial.begin(115200);
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
}
float getdistance()
{
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(18);
  duration = pulseIn(echo,HIGH);
  return {duration*0.034/2};
}
void loop()
{
  distance = getdistance();
  Serial.println("distance:"+String(distance));
  Serial.println(("<----------------->"));
  delay(3000);
}