arduino_Ultra_distance_led_three

const int ledRed = 13;
const int ledBlue = 12;
const int ledGreen = 11;

const int trig = 3;
const int echo = 2;
void setup() {
  // put your setup code here, to run once:
  pinMode(ledRed, OUTPUT);
  pinMode(ledBlue , OUTPUT);
  pinMode(ledGreen, OUTPUT);
  pinMode(trig, OUTPUT);
  pinMode(echo, INPUT);
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

  long distance = pulseIn(echo, HIGH)/58.2;
  delay(10);
  Serial.print(distance);
  Serial.println(" cm");
  if(distance > 4 && distance <15)
  {   
    digitalWrite(ledBlue, LOW);
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledRed, HIGH);
    delay(500);
  }
  else if(distance >= 15 && distance <30)
  {
    digitalWrite(ledRed, LOW);
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledBlue, HIGH);
    delay(500);
  }
   else
  {   
    digitalWrite(ledRed, LOW);
    digitalWrite(ledBlue, LOW);
    digitalWrite(ledGreen, HIGH);
    delay(500);
  }
}