Complete PID Electric Smoker Control with Bluetooth

// Note: The format offered here does not allow sufficient space on one line
// to accomidate lengthy comments. Some changes may be necessary in the form
// of "//" if the code is to be cut and pasted but may be ok if pasted into 
// the Arduino compiler

//				Start of Arduino Sketch:

#include <LiquidCrystal_I2C.h> // Library for I2C LCD
#include <OnewireKeypad.h>     // OneWireKeypad Library

char KEYS[] = {                // Define keys values of Keypad
  '1', '2', '3',
  '4', '5', '6',
  '7', '8', '9',
  '*', '0', '#'};

#include <SPI.h>                //The two max6675 thermocouples use SPI communications
#include <Thermocouple.h>       //This is the max6675 library that works (could not use "include max6675.h" library)
#define csTC1 9                 //chip select for MAX6675 #1 (SPI)--Smoker temperature--TC1--Orange wire 
#define csTC2 10                //chip select for MAX6675 #2 (SPI)--Meat temperature--TC3--Blue wire
#include <PID_v1.h>             //Library for implementing PID control of the set Smoker temperature
#include <Wire.h>               // Allows the use of the I2C bus
Thermocouple tc1 = Thermocouple(csTC1);  //Identify Thermocouple (from library) as Smoker pin 9
Thermocouple tc2 = Thermocouple(csTC2);  //Identify Thermocouple (from library) as Smoker pin 10
OnewireKeypad <Print, 12 > Keypad(Serial, KEYS, 4, 3, A0, 4700, 1000 );  // Defines keypad as a 4 row, 3 column device //with pin A0 input along with the voltage dividing resistance value.
                                                             
LiquidCrystal_I2C lcd(0x3F, 16, 2); // Provides the I2C Bus address and defines the LCD as a 16 char, 2 line device
double Input;            // declare Input to be a double variable because the PID control library uses double (not interger) variables
double Input2;
double Input3;
double InputAve;    
int RelayPin = 8;        // declare pin8 for relay control
int alert = 7;           // declare pin7 for alert control
const int tempMax = 320; // declare tempMax to be a constant 320 (degreeF)as the maximum temperature the smoker can reach
double tempSmoke = 0;    // declare tempSmoke to be a double variable of the internal temp. of the smoker (DegF) read from thermocouple1
int tempMeat = 0;        // declare tempMeat to be an interger value of the internal temp. of the meat being smoked (DegF) read from thermocouple2
int tempMeat1 = 0;
int tempMeat2 = 0;
int tempMeatAve = 0;     // tempMeatAve is the average of three tc2 readings to increase the accuracy of the actual meat temp reading
int keypress = 0;        // Set to 0 to eliminate any residual values from previous cycles
int keypress1 = 0;
int keypress2 = 0;
double Setpoint;         // declare 'Setpoint' as the value entered from the keypad as the desired maximum internal smoker temp.
int SetMeatTemp;         // declare SetMeatTemp as the value entered from the kaypad as the desired maximum internal meat temp.
char Stop=0;             // Sets the variable 'Stop' to zero to enable use of the 'while' function
char Str1[15] = "CYCLE COMPLETE";  // declare a character string variable to be used at the end of the smoking cycle
char Str2[15] = "ENJOY DINNER!!";  // declare a character string variable to be used at the end of the smoking cycle
double  Output;                    //Define Variables we'll be connecting to for PID control
int Input1=Input;        // declare 'Input1' as an integer so the places past the decimal are dropped for the Android (BT) display
int Setpoint1=Setpoint;  // declare 'Setpoint1' as an integer so the places past the decimal are dropped for the Android (BT) display
PID myPID(&InputAve, &Output, &Setpoint,150,1,1, DIRECT); //Specify the links and initial tuning parameters for PID control
int WindowSize = 3500;
unsigned long windowStartTime;


void setup ()
{
  
  Serial.begin(9600);
  windowStartTime = millis();

  myPID.SetOutputLimits(0, WindowSize);  //tell the PID to range between 0 and the full window size
  
  myPID.SetMode(AUTOMATIC);              //activate the PID
  pinMode(RelayPin, OUTPUT);             //declare pin8 as an output to the 120v relay to turn power on or off to the heating coil
  lcd.init();
  lcd.backlight();
  Wire.begin();
  Keypad.SetHoldTime(100);
  Keypad.Getkey();
  lcd.begin(16, 2);
  lcd.clear();           
  pinMode(alert, OUTPUT);                // declare pin7 as output for the alert
  lcd.print("SMOKE TEMP?");              //Displays 'SMOKE TEMP?' on LCD
                       
  delay(100);                            //Allows everything to get set
}
void loop()
{ // The following section of the code reads the desired temperature for the smoker and the meat and sets up a 3 digit integer using
  //  (int number = 100 * int1 + 10 * int2 + int3) for the variables 'Setpoint' and 'SetMeatTemp'.

  // 1st digit of the desired smoker temperature:

  while (Stop == 0) {   // Allows void loop to be executed in segments to control when events happen. Without 'while' the ketpress is a random entry.
    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
    {
      lcd.setCursor(13, 0);

      keypress = Keypad.Getkey();
      while ((Keypad.Key_State())) {} // Stay here until Key is held down
      keypress = keypress - '0';
      lcd.print(keypress);
      Stop = 1;
    }
  }

  //2nd digit smoke:
  while (Stop == 1) {
    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
    {
      lcd.setCursor(14, 0);
      keypress1 = Keypad.Getkey();
      while ((Keypad.Key_State())) {} // Stay here until Key is held down
      keypress1 = keypress1 - '0';
      lcd.print(keypress1);
      Stop = 2;
    }
  }
  //3rd digit smoke:
  while (Stop == 2) {
    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
    {
      lcd.setCursor(15, 0);
      keypress2 = Keypad.Getkey();
      while ((Keypad.Key_State())) {} // Stay here until Key is held down
      keypress2 = keypress2 - '0';
      lcd.print(keypress2);
      Stop = 3;
    }
  }

  while (Stop == 3) {
    Setpoint = 100 * keypress + 10 * keypress1 + keypress2; // Combines the three entered digits into one (3 digit) variable called 'SetSmokeTemp'.

    lcd.setCursor(0, 1);
    delay(10);
    lcd.print("MEAT TEMP?");                            //Displays 'MEAT TEMP' on LCD
    Stop = 4;
  }
  // 1st digit of the desired meat temperature:
  while (Stop == 4) { // Allows void loop to be executed in segments to control when events happen

    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
    {
      lcd.setCursor(13, 1);
      keypress = Keypad.Getkey();
      while ((Keypad.Key_State())) {} // Stay here until Key is held down
      keypress = keypress - '0';
      lcd.print(keypress);
      Stop = 5;
    }
  }
  //2nd digit meat:
  while (Stop == 5) {
    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
    {
      lcd.setCursor(14, 1);
      keypress1 = Keypad.Getkey();
      while ((Keypad.Key_State())) {} // Stay here until Key is held down
      keypress1 = keypress1 - '0';
      lcd.print(keypress1);
      Stop = 6;
    }
  }

  //3rd digit meat:
  while (Stop == 6) {
    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
    {
      lcd.setCursor(15, 1);
      keypress2 = Keypad.Getkey();
      while ((Keypad.Key_State())) {} // Stay here until Key is held down
      keypress2 = keypress2 - '0';
      SetMeatTemp = 100 * keypress + 10 * keypress1 + keypress2; //Combines the 3 entered digits into one (3 digit) variable called 'SetMeatTemp'.
      lcd.print(keypress2);
      Stop = 7;
    }
  }
  
  delay(50);                  // Provides a delay before the cycle begins
 
  Input = (tc1.readF()-19);    //'Input' is the reading of the actual internal smoker temperature adjusted(-19deg)to match the Redi reading(at225deg)
  delay(350);
  
  Input2=(tc1.readF()-19);
  delay(350);
  
  Input3=(tc1.readF()-19);
  delay(350);
  
  InputAve=(Input+Input2+Input3)/3;  //The average of 3 readings is a bit more accurate
  
  if (InputAve>335){InputAve=225;}  //Prevents a 'flier' from shutting down the program (max temp 320)
  
  delay(350);                 //the Max 6675 board is slow and should not be read more than 3 times per second
  tempMeat = (tc2.readF()); //The reading from Thermocouple2 becomes the variable 'tempMeat' adjustment not needed to match the Redi reading(at165deg)
 
  delay(350);                 //the Max 6675 board is slow and should not be read more than 3 times per second
  tempMeat1 = (tc2.readF());
  
  delay(350);
  tempMeat2 = (tc2.readF());
 
  delay(350);
  if(tempMeat>tempMeat1+5||tempMeat<tempMeat1-5){tempMeat=100;tempMeat1=100;Serial.print("flier1 ");} //prevents 'fliers' from adversely affecting    //the program
  if(tempMeat>tempMeat2+5||tempMeat<tempMeat2-5){tempMeat=100;tempMeat2=100;Serial.print("flier2");}  //prevents' fliers' from adversely affecting //the program
  tempMeatAve = (tempMeat+tempMeat1+tempMeat2)/3;                          //Accuracy improved by averaging readings
  
  if(tempMeatAve>SetMeatTemp+10){tempMeatAve=150;Serial.print("flier3");}  //prevents 'fliers' from adversely affecting the program
 

                  // The following 7 lines turns the output pin on/off based on PID output

  myPID.Compute();  
  
  unsigned long now = millis();
  
  if(now - windowStartTime>WindowSize)
  { 
    windowStartTime += WindowSize;  //time to shift the Relay Window
  }
  if(Output > (now - windowStartTime)){ 
   digitalWrite(RelayPin, HIGH);Serial.println("ON"); 
    }
  else {digitalWrite(RelayPin,LOW);Serial.println("OFF");}//}
                       
    lcd.clear();                     // The following 17 lines set up the LCD display to indicate the Set & Actual temperatures
    lcd.setCursor(0, 0);
    lcd.print("SKset");
    lcd.setCursor(5, 0);
    lcd.print(Setpoint);
    lcd.setCursor(9, 0);
    lcd.print("ACT");
    lcd.setCursor(13, 0);
    lcd.print(InputAve);
    lcd.setCursor(0, 1);
    lcd.print("MTset");
    lcd.setCursor(5, 1);
    lcd.print(SetMeatTemp);
    lcd.setCursor(9, 1);
    lcd.print("ACT");
    lcd.setCursor(13, 1);
    lcd.print(tempMeatAve);
    
    Serial.print("SmokerSetTemp=");  // All "Serial.print" and "Serial.println" commands are to send status of smoker to Android BT device
    Setpoint1=Setpoint;
    Serial.print(Setpoint1);
    Serial.print("   ");
    Serial.print("ActualTemp=");
    Input1=InputAve;
    Serial.print(Input1);             
    Serial.println();
    Serial.println();
    Serial.print("MeatSetTemp  =  ");
    Serial.print(SetMeatTemp);
    Serial.print("   ");
    Serial.print("ActualMeatTemp=");
    Serial.print(tempMeatAve);
    Serial.println();
    Serial.println();
    Serial.println(); 
    Serial.println();
    Serial.println();
    Serial.println();
    Serial.println();
    Serial.println();
    Serial.println();       
    delay(50);
    
  if (InputAve>=tempMax)                       // The following 8 lines monitor the maximum temperature of 320deg, shuts down the cycle, 
    {digitalWrite(RelayPin, LOW);           //                                                          sends an alert to the display, and buzzer
                                           
    lcd.clear();                            
    lcd.setCursor(0,0); 
    lcd.print("TEMPERATURE OUT"); 
    lcd.setCursor(0,1);
    lcd.print(" OF CONTROL!!!");
    digitalWrite(alert, HIGH);}   
  
  if (tempMeatAve >= SetMeatTemp)            // When tempMeat(from MAX6675(2)(thermocouple in meat))equals the meat set temp turn smoker coil OFF,
                                             // indicate CYCLE COMPLETE on display, sound the Alert, and stop the Smoker cycle
  {
    digitalWrite(RelayPin, LOW);             //"Stops"the smoking cycle (until the meat temp drops below the meat set temp)
    Serial.println("                      DINNER IS READY");  //Sends message to Android BT device
    Serial.println("                     COME AND GET IT!");  //Sends message to Android BT device
    Serial.println();
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print(Str1);                         // print "CYCLE COMPLETE" on first line of LCD display
    lcd.setCursor(0, 1);
    lcd.print(Str2);                         // print "ENJOY DINNER!!" on second line of LCD display
    digitalWrite(alert, HIGH);               // Sets off the alert buzzer 
    delay(150);
    digitalWrite(alert, LOW);                // Provides a short 'beep-beep' instead of an annoying constant single'beeeeeeeep'
    delay(150);
    digitalWrite(alert, HIGH);
    delay(150);
    digitalWrite(alert, LOW);
    delay(3000);}
    }