/*
ARDUINO TRAINING 
CREATE BY : MUHAMMAD SHAHKHIR BIN MOZAMIR

TITLE: ULTRASONIC SENSOR AND LED AND BUZZER WITH EXTRA LEDS
*/

const int trigPin = 9;
const int echoPin = 10;
long duration;
int distance;
int Buzzer = 4;
int LED_1 = 13; // LED for distance < 7 cm
int LED_2 = 12; // LED for distance between 7 cm and 15 cm
int LED_3 = 11; // LED for distance > 15 cm

void setup() {
  // put your setup code here, to run once:
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(Buzzer, OUTPUT);
  pinMode(LED_1, OUTPUT);
  pinMode(LED_2, OUTPUT);
  pinMode(LED_3, OUTPUT);
  Serial.begin(9600);
}

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

  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  Serial.print("Distance : ");
  Serial.print(distance);
  Serial.println(" cm");

  // Control LEDs and Buzzer based on distance
  if (distance < 7) {
    digitalWrite(Buzzer, HIGH);
    digitalWrite(LED_1, HIGH);
    digitalWrite(LED_2, LOW);
    digitalWrite(LED_3, LOW);
    delay(500);
    digitalWrite(Buzzer, LOW);
    delay(500);
  }
  else if (distance >= 7 && distance <= 15) {
    digitalWrite(Buzzer, LOW);
    digitalWrite(LED_1, LOW);
    digitalWrite(LED_2, HIGH);
    digitalWrite(LED_3, LOW);
  }
  else {
    digitalWrite(Buzzer, LOW);
    digitalWrite(LED_1, LOW);
    digitalWrite(LED_2, LOW);
    digitalWrite(LED_3, HIGH);
  }

  delay(1000);
}

/*
 *TEST STATUS : QUALIFIED
 */