//define the sensor pins
#define echoPin1 11
#define trigPin1 12
#define echoPin2 4
#define trigPin2 3
#define echoPin3 10
#define trigPin3 7

#define trigDistance 15

//define the LED pins and buzzer
#define redLED 8
#define greenLED 9
#define blueLED 5
#define buzzer 2

// defines variables
long duration1, duration2, duration3;
int distance1, distance2, distance3;

unsigned long prevMillis; //Timing variable

void readSensors() {
    // Clears the trigPin
  digitalWrite(trigPin1, LOW);
  digitalWrite(trigPin2, LOW);
  digitalWrite(trigPin3, LOW);
  delayMicroseconds(2);

  // Sets the trigPin on HIGH state for 10 micro seconds and read duration
  digitalWrite(trigPin1, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin1, LOW);
  duration1 = pulseIn(echoPin1, HIGH);

  digitalWrite(trigPin2, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin2, LOW);
  duration2 = pulseIn(echoPin2, HIGH);

  digitalWrite(trigPin3, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin3, LOW);
  duration3 = pulseIn(echoPin3, HIGH);
  

  // Calculating the distance
  distance1 = duration1 * 0.034 / 2;
  distance2 = duration2 * 0.034 / 2;
  distance3 = duration3 * 0.034 / 2;

  // Prints the distance on the Serial Monitor every seconds
  if (millis() - prevMillis >= 1000){
    Serial.println();
    Serial.print("Distance 1: ");
    Serial.print(distance1);
    Serial.println("cm");
    Serial.print("Distance 2: ");
    Serial.print(distance2);
    Serial.println("cm");
    Serial.print("Distance 3: ");
    Serial.print(distance3);
    Serial.println("cm");

    prevMillis = millis();
  }
}

void setup() {
  // Sets the trigPins as an Output
  pinMode(trigPin1, OUTPUT);
  pinMode(trigPin2, OUTPUT);
  pinMode(trigPin3, OUTPUT);

  // Sets the echoPins as an Input
  pinMode(echoPin1, INPUT);
  pinMode(echoPin2, INPUT);
  pinMode(echoPin3, INPUT);

  // Sets the LEDs and buzzer as an Output
  pinMode(redLED, OUTPUT);
  pinMode(blueLED, OUTPUT);
  pinMode(greenLED, OUTPUT);

  digitalWrite(redLED, LOW);

  // Starts the serial communication
  Serial.begin(9600);
}
void loop() {
  readSensors();

  if (distance1 <= trigDistance){
    digitalWrite(redLED, HIGH);
    tone(buzzer, 1047, 500);
  }else{
    digitalWrite(redLED, LOW);
  }

  if (distance2 <= trigDistance){
    digitalWrite(greenLED, HIGH);
    tone(buzzer, 1319, 500);
  }else{
    digitalWrite(greenLED, LOW);
  }

  if (distance3 <= trigDistance){
    digitalWrite(blueLED, HIGH);
    tone(buzzer, 1568, 500);
  }else{
    digitalWrite(blueLED, LOW);
  }
}