AURDINO SONAR SENSOR PROJECT

int trigpin=A1, echopin = A2,ledpin =A3;
float duration,distance;
void setup(){
  pinMode(trigpin,OUTPUT);
  pinMode(echopin,INPUT);
  pinMode(ledpin,OUTPUT);
  Serial.begin(9600);

}
void loop(){

 digitalWrite(trigpin,LOW);
  delay(2);
  digitalWrite(trigpin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin,LOW);
  duration = pulseIn(echopin,HIGH);
  distance =( duration * 0.034 * 0.5);
  if(distance<=100){
     digitalWrite(ledpin,HIGH);

  }else{

    digitalWrite(ledpin,LOW);
  }
  Serial.print("The distance is: ");
  Serial.print(distance);
  Serial.print("cm\n");
  delay(500);
}