// ---------------------------------------------------------------- //
//  Arduino Distance Classification Using Ultrasonic Sensor 
//
//  Date: 10/28/2022
//
//  Author: Brayan Trejo
//  Email:  brayan.trejo@colostate.edu
//
//  Department of Electrical and Computer Engineering 
//  Colorado State University 
//
//  Revised 11/1/2023 with suggestions from Ross and Fatimah
// ---------------------------------------------------------------- //


// Define Arduino Pinout connections
#define PIN_ECHO 2          // Connect Arduino pin 2 ---> Echo pin of Ultrasonic Sensor
#define PIN_TRIG 3          // Connect Arduino pin 3 ---> Trig pin of Ultrasonic Sensor

#define PIN_BUZZER 11        // Connect Arduino pin 11 ---> Positive terminal of Buzzer. Fun fact- certain pins have PWM capabilities.
#define PIN_GREEN_LED 5     // Connect Arduino pin 5 ---> Positive terminal of Green LED 
#define PIN_BLUE_LED 6      // Connect Arduino pin 6 ---> Positive terminal of Blue LED 
#define PIN_RED_LED 7       // Connect Arduino pin 7 ---> Positive terminal of Red LED 


// Define variables used for calculating and classifying distance 
double duration;        // Variable for the duration of sound wave round-trip travel
double distance;        // Variable for the distance measurement

// ***TO DO***: ENTER THRESHOLD VALUES (in centimeters), MAXIMUM VALUE = 50
int long_range = ;      // Variable that sets maximum detection distance 
int mid_range = ;       // Variable that sets mid-range detection distance 
int close_range = ;     // Variable that sets close-range detection distance 


// ***TO DO***: Setup code. Runs only one time.Setup the respective pins to be either Outputs or Inputs. 
void setup() {   
  pinMode(PIN_TRIG, );           // Sets the Trig Pin as an OUTPUT
  pinMode(PIN_ECHO, );            // Sets the Echo Pin as an INPUT
  pinMode(PIN_BUZZER, );         // Sets the Buzzer Pin as an OUTPUT
  pinMode(PIN_RED_LED, );        // Sets the Red LED Pin as an OUTPUT
  pinMode(PIN_BLUE_LED, );       // Sets the Blue LED Pin as an OUTPUT
  pinMode(PIN_GREEN_LED, );      // Sets the Green LED Pin as an OUTPUT
  Serial.begin(9600);                  // Starts the serial communication with the PC 
  Serial.println("Distance Classification System With Arduino Uno R3");  // Prints text to the serial monitor

}


 // MAIN CODE: RUNS REPEATEDLY
void loop() { 
  distance = get_Distance();
  classify_Distance(distance);
  delay(5);
}


// ********************************************** PROGRAM FUNCTIONS *********************************************

// This function computes the distance of an object using the ultrasonic sensor module. 
double get_Distance(){
  digitalWrite(PIN_TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(PIN_TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(PIN_TRIG, LOW);
  duration = pulseIn(PIN_ECHO, HIGH);   // Returns the soundwave travel time in microseconds
  distance = duration * 0.034 / 2.0;    // Calculates the distance
  Serial.print("Distance: ");           // Prints the distance to the PC
  Serial.print(distance);
  Serial.println(" cm");
  return distance; 
}


// This function accepts the distance calculation and classifies its range (i.e., FAR, MID, CLOSE). 
void classify_Distance(double distance){

// ***TO DO***: ENTER HIGH or LOW for all digitalWrite statements below. HIGH= Turn on, LOW=turn off.  
  if(distance > long_range){
    Serial.print("\nOBJECT OUT OF RANGE - ");
    digitalWrite(PIN_GREEN_LED, );
    digitalWrite(PIN_BLUE_LED,  );
    digitalWrite(PIN_RED_LED,   );
  }
  else if ((distance < long_range) && (distance > mid_range)){
    Serial.print("\nOBJECT DETECTED - RANGE=FAR - ");
    digitalWrite(PIN_GREEN_LED, );
    digitalWrite(PIN_BLUE_LED,  );
    digitalWrite(PIN_RED_LED,   );
}
  else if ((distance < mid_range) && (distance > close_range)){
    Serial.print("\nOBJECT DETECTED - RANGE=MID - ");
    digitalWrite(PIN_GREEN_LED, );
    digitalWrite(PIN_BLUE_LED,  );
    digitalWrite(PIN_RED_LED,   );
  }
  else {
    Serial.print("\nOBJECT DETECTED - RANGE=CLOSE - ");
    digitalWrite(PIN_GREEN_LED, );
    digitalWrite(PIN_BLUE_LED,  );
    digitalWrite(PIN_RED_LED,   );
    make_sound();
  }
}


// ***TO DO***: This function generates a sound on the buzzer and uses PWM to change the audio signal. Enter a value between 0 and 255.
void make_sound(){
  analogWrite(PIN_BUZZER, );     //This value is the max % of the dutyCycle. 
  delay(500);
  analogWrite(PIN_BUZZER, 0);

}