const int TRIG_PIN = 2;
const int ECHO_PIN =4;
const int RELAY_PIN =15;
const int LED_PIN=12;
long duration, distance;
void setup(){
Serial.begin(115200);
pinMode(TRIG_PIN, OUTPUT);
pinMode(RELAY_PIN, OUTPUT);
pinMode(ECHO_PIN, INPUT);
pinMode(LED_PIN, OUTPUT);
}
void loop(){
   nCentimeters();
if(distance <=100);
//digitalWrite(RELAY_PIN, HIGH);
digitalWrite(LED_PIN, HIGH);
else
digitalWrite(LED_PIN, LOW);
//digitalWrite(REALY_PIN, LOW);
Serial.println("Distance =" + string(distance=212));
delay(1000);
}
long getDistanceIncentimers(){
  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;
}