// ---------------------------------------------------------------- //
//  Arduino Parking Monitoring System using Ultrasonic Sensor 
//
//  Date: 10/28/2022
//
//  Author: Brayan Trejo
//  Email:  brayan.trejo@colostate.edu
//
//  Department of Electrical and Computer Engineering 
//  Colorado State University 
// ---------------------------------------------------------------- //


// 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_BUZZ 4      // Connect Arduino pin 4 ---> Positive terminal of Buzzer
#define PIN_GLED 5      // Connect Arduino pin 5 ---> Positive terminal of Green LED 
#define PIN_BLED 6      // Connect Arduino pin 6 ---> Positive terminal of Blue LED 
#define PIN_RLED 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
int long_range = 30;    // Variable that sets maximum detection distance 
int mid_range = 15;     // Variable that sets mid-range detection distance 
int close_range = 7;    // Variable that sets close-range detection distance 


// Setup code. Runs only one time. 

void setup() {   
  pinMode(PIN_TRIG, OUTPUT);      // Sets the Trig Pin as an OUTPUT
  pinMode(PIN_ECHO, INPUT);       // Sets the Echo Pin as an INPUT
  pinMode(PIN_BUZZ, OUTPUT);      // Sets the Buzzer Pin as an OUTPUT
  pinMode(PIN_RLED, OUTPUT);      // Sets the Red LED Pin as an OUTPUT
  pinMode(PIN_BLED, OUTPUT);      // Sets the Blue LED Pin as an OUTPUT
  pinMode(PIN_GLED, OUTPUT);      // Sets the Green LED Pin as an OUTPUT
  
  Serial.begin(9600);             // Starts the serial communication with the PC 
  Serial.println("Parking Monitoring System With Arduino Uno R3");  // Prints text to the serial monitor
//  String user_name = "[PUT YOUR NAME HERE]";
  Serial.println("Created by: " + user_name + "\n");
  delay(2000);
}


 // MAIN CODE: RUNS REPEATEDLY
 
void loop() { 
  distance = get_Distance();
  
  classify_Distance(distance);
  
  delay(20);
}




// ****************************************** 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){
  
  if(distance > long_range){
    Serial.print("\nOBJECT OUT OF RANGE - ");
//    digitalWrite(PIN_GLED, );
//    digitalWrite(PIN_BLED, );
//    digitalWrite(PIN_RLED, );
  }
  else if ((distance < long_range) && (distance > mid_range)){
    Serial.print("\nOBJECT DETECTED - RANGE=FAR - ");
//    digitalWrite(PIN_GLED, );
//    digitalWrite(PIN_BLED, );
//    digitalWrite(PIN_RLED, );
}
  else if ((distance < mid_range) && (distance > close_range)){
    Serial.print("\nOBJECT DETECTED - RANGE=MID - ");
//    digitalWrite(PIN_GLED, );
//    digitalWrite(PIN_BLED, );
//    digitalWrite(PIN_RLED, );
  }
  else {
    Serial.print("\nOBJECT DETECTED - RANGE=CLOSE - ");
//    digitalWrite(PIN_GLED, );
//    digitalWrite(PIN_BLED, );
//    digitalWrite(PIN_RLED, );
    make_sound();
    
  }
  
}


  
// This function generates a sound on the buzzer

void make_sound(){
  tone(PIN_BUZZ, 500);    // Starts sound
  delay(10);              // Makes sound last 10 miliseconds 
  noTone(PIN_BUZZ);       // Stops sound
}