/* Program: Remote Car Start
* Author:  Chris Johnson
* Revised: December 5th, 2011
*
* Inputs:  BT Module "ON" signal
*          BT Module "OFF" signal
*          Vehicle RPM Sensor
*          Vehicle Neutral Position Sensor
*          Vehicle Speed Sensor
*          Serial port
* Outputs: Ignition Control Relay
*          Accessory Control Relay
*          Starter Control Relay
*          Clutch Safety Switch Relay
*          Serial Port
*/


//EQUATES
//Inputs
int BT_on = 2;                                               //Bluetooth "ON" signal inputed to pin 2
int RPM_sens = 3;                                       //Vehicle RPM sensor inputted to pin 3
int speed_sens = 5;                                     //Vehicle Speed Sesor inputted to pin 5
int BT_off = 7;                                                //Bluetooth "OFF" signal inputed on pin 7

//Outputs
int ign_ctrl = 8;                                               //Ignition Control Relay controlled by pin 8
int start_ctrl = 9;                                             //Start Control Relay controlled by pin 9
int acc_ctrl = 11;                                            //Accessory Control Relay controlled by pin 11

unsigned long start_time;                            //Variable used to store the time at which the starter is engaged

char data = 0;                                                 //Variable used to store data received via the serial port

//DEFINITIONS
void setup()
{
  pinMode(BT_on, INPUT);                          //Define pin inputs and outputs
  pinMode(RPM_sens, INPUT);
  pinMode(speed_sens, INPUT);
  pinMode(BT_off, INPUT);

  pinMode(ign_ctrl, OUTPUT);
  pinMode(start_ctrl, OUTPUT);
  
  pinMode(acc_ctrl, OUTPUT);

  Serial.begin(9600);                                     //Initialize the serial port with a baud rate of 9600
}

//PROGRAM

//Loop function: Wait for a START command to be received (command via serial port or
//voltage applied to BT_on pin)
void loop()
{
   if (Serial.available() > 0)                          //Check if any serial data is available
   {
     data = Serial.read();                                //Set "data" variable to currently available serial data
     check();                                                      //Go to "check" funtion if serial data is available
   }
   else if (digitalRead(BT_on) == HIGH)     //Check if BT Module has set pin high
   {
     begin();                                                       //Begin start sequence if pin is high
   }
   else
   {
     loop();                                                          //Repeat this function until a START command is received
   }
}

//Check function: Test for proper character set from BT
void check()                           
{
  if (data == 's')                                          //Check if an "s" has been sent
  {
    begin();                                                  //Begin start sequence if "s" has been sent
  }
  else
  {
    Serial.println("Invalid Command");  //If anything other than an "s" has been sent, send "Invalid Command" error message
    loop();                                                    //Return to beginning of program
  }
}

//Begin function: Turn on accessory and ignition
void begin()
{
  delay(500);                                     // 0.5 second delay
  digitalWrite(acc_ctrl, HIGH);        //Turn accessory ON
  digitalWrite(ign_ctrl, HIGH);         //Turn ignition ON
  delay(500);                                      // 0.5 second delay
 
}



//Start function: Engage starter only if engine is not already running.
void start()
{
   int RPM = pulseIn(RPM_sens, HIGH, 1000000);    //Get RPM value
   if(RPM == 0)                                                                   //Continue start sequence only if vehicle is not running.
   {
     
     digitalWrite(acc_ctrl, LOW);                   //Turn accessory OFF
     delay(500);                                               //0.5 second delay
     digitalWrite(start_ctrl, HIGH);                //Engage starter
     start_time = millis();                                //Capture the time at which the starter was engaged
     starter_engaged();                                 //Go to Starter_engaged function
   }
   else                                         
   {
     Serial.println("Vehicle Already Running");  //Send "Vehicle Already Running" message if engine was previously started
     vehicle_off();                                                    //Exit start sequence if already running
   }
}

//Starter_engaged function: Disengage starter after vehicle is starter or turn off starter if
//vehicle has not started within 4 seconds.
void starter_engaged()
{
  int RPM = pulseIn(RPM_sens, HIGH);            //Get RPM value
  if (RPM > 1000)                                                   //Continue if engine has started (reached low idle)
  {
    Serial.println("Engine Running");                  //Send "Engine Running" message after engine has started
    disengage_starter();                                        //Go to disengage_starter after engine is running
  }
  else if ((start_time+4000) < millis())                //Test if 4 seconds has passed since the starter was engaged
  {

    disengage_starter_timeout();                 //Go to disengage_starter if engine has not started within 4 seconds of starter engagement
  }
  else
  {
    starter_engaged();                                    //Repeat this function if engine has not started or 4 seconds has not elapsed
  }
}

//Disengage_starter function: Disengage the starter.
void disengage_starter()
{
  digitalWrite(start_ctrl, LOW);                   //Disengage the starter
  
  digitalWrite(acc_ctrl, HIGH);                   //Turn accessory ON
  vehicle_off_sense();                                //Go to vehicle_off_sense function
}

//Disengage_starter_timeout function: Disengage the starter (used after 4 seconds has elapsed without an engine start)
void disengage_starter_timeout()
{
  digitalWrite(start_ctrl, LOW);                                 //Disengage the starter
  
  Serial.println("Vehicle Start Unsuccessful");      //Send "Vehicle Start Unsuccessful"
  vehicle_off();                                                            //Exit start sequence
}

//Vehicle_off_sense function: Waits for an "off" signal to be sent while the engine is running.
//If no "off" signal is received, turns off the vehicle after 30 minutes has elapsed since the engine start.
void vehicle_off_sense()
{
  int moving = pulseIn(speed_sens, HIGH);                //Get vehicle speed
  if (moving > 1000)                                                         //Check if vehicle is moving
  {
    Serial.println("Vehicle OFF -- Movement");           //Send "Vehicle OFF -- Movement" message ifvehcile is moving
    vehicle_off();                                                               //Turn vehicle off if it is moving
  }
  else if (start_time+600000 < millis())                    //Check if 30 minutes has elapsed since engine start
  {
    Serial.println("Vehicle OFF -- Automatic Timeout");  //Send "Vehicle OFF -- Automatic Timeout" message if engine has been                            
                                                                                                     //running for 30 minutes
    vehicle_off();                                                                    //Turn vehicle off if engine is running for 30 minutes
  }
  else if (Serial.available() > 0)                                         //Check if a signal has been sent via serial data
  {
    data = Serial.read();                                                      //Store serial sent serial data
    if (data == 'o')                                                                  //Check if signal sent is an OFF command ("o")
    {
      Serial.println("Vehicle OFF -- User Commanded");   //Send "Vehicle OFF -- User Commanded" message if serial data is the OFF
                                                                                                        //command ("o")
      vehicle_off();                                                                     //Turn vehicle off if OFF command is sent via serial data
    }
  }
  else if (digitalRead(BT_off) == HIGH)                              //Check if OFF command has been sent via BT module
  {
    Serial.println("Vehicle OFF -- User Commanded");     //Send "Vehicle OFF -- User Commanded" message if OFF
                                                                                                        //command was sent
    vehicle_off();                                                                       //Turn vehicle off if OFF command was sent via BT module
  }
  else
  {
    vehicle_off_sense();                                                   //Repeat this function if none of the above conditions have been met
  }
}

//Vehicle_off function: Turns the vechile off and starts the whole program over
void vehicle_off()
{
  digitalWrite(ign_ctrl, LOW);                           //Turn ignition OFF
  digitalWrite(acc_ctrl, LOW);                           //Turn accessory OFF
  loop();                                                //Repeat program (look for start command)
}