// defines pins numbers
const int trigPin = 12;
const int echoPin = 13;
const int SW = 3;
const int BUZZER = A0;
const int LED_L = A3;
const int LED_R = A2;
const int LED_B = 7;

// defines variables
long duration;
int distance;
void setup() {
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  pinMode(SW, INPUT_PULLUP); // sets sw to input pull_up
  pinMode(BUZZER, OUTPUT); // Sets the output buzzer
  pinMode(LED_L, OUTPUT);
  pinMode(LED_R, OUTPUT);
  pinMode(LED_B, OUTPUT);
  pinMode(LED_L, OUTPUT);
  
  Serial.begin(9600); // Starts the serial communication
}
void loop() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance = (duration * 0.034 / 2)+1; //distance in cm,
  // Prints the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  if (digitalRead(SW) == LOW){
    if ((distance > 10)&&(distance <= 30)){
      digitalWrite(LED_L, HIGH);
      digitalWrite(LED_R, HIGH);
      delay(300);
      digitalWrite(LED_L, LOW);
      digitalWrite(LED_R, LOW);
      delay(300);
    }
    else if ((distance >= 0)&&(distance <= 10)){
      digitalWrite(BUZZER, HIGH);
      digitalWrite(LED_B, HIGH);
      delay(300);
      digitalWrite(BUZZER, LOW);
      digitalWrite(LED_B, LOW);
      delay(300);
    }
    else;
  }
  else;
}