const int TRIG_PIN=2;
const int ECHO_PIN=4;
long duration,distance;
void setup(){
  Serial.begin(115200);
  pinMode(TRIG_PIN,OUTPUT);
  pinMode(ECHO_PIN,INPUT);
}
void loop(){
  distance=getDistanceInCentimeters();
  Serial.println("Distance="+String(distance));
  delay(1000);
}
long getDistanceInCentimeters(){
  digitalWrite(TRIG_PIN,LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN,HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN,LOW);
  duration=pulseIn(ECHO_PIN,HIGH);
  return(duration*0.034/2)+1;
}