const int echo=14;
const int trig=27;
float distance;
float duration;

void setup() {
  Serial.begin(115200);
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
}
float getdistance()
{
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig,LOW);
  duration = pulseIn(echo,HIGH);
  return (duration*0.034/2);
}
void loop()
{
  distance=getdistance();
  Serial.println("distance:"+String(distance));
  Serial.println("<--------------------->");
  delay(3000);
}