Complete PID Electric Smoker Control with Bluetooth

1
2// Note: The format offered here does not allow sufficient space on  one line
3// to accomidate lengthy comments. Some changes may be necessary in  the form
4// of "//" if the code is to be cut and pasted but may be ok if pasted  into 
5// the Arduino compiler
6
7//				Start of Arduino Sketch:
8
9#include  <LiquidCrystal_I2C.h> // Library for I2C LCD
10#include <OnewireKeypad.h>     //  OneWireKeypad Library
11
12char KEYS[] = {                // Define keys values  of Keypad
13  '1', '2', '3',
14  '4', '5', '6',
15  '7', '8', '9',
16  '*',  '0', '#'};
17
18#include <SPI.h>                //The two max6675 thermocouples  use SPI communications
19#include <Thermocouple.h>       //This is the max6675  library that works (could not use "include max6675.h" library)
20#define csTC1  9                 //chip select for MAX6675 #1 (SPI)--Smoker temperature--TC1--Orange  wire 
21#define csTC2 10                //chip select for MAX6675 #2 (SPI)--Meat  temperature--TC3--Blue wire
22#include <PID_v1.h>             //Library for implementing  PID control of the set Smoker temperature
23#include <Wire.h>               //  Allows the use of the I2C bus
24Thermocouple tc1 = Thermocouple(csTC1);  //Identify  Thermocouple (from library) as Smoker pin 9
25Thermocouple tc2 = Thermocouple(csTC2);  //Identify Thermocouple (from library) as Smoker pin 10
26OnewireKeypad <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.
27                                                             
28LiquidCrystal_I2C  lcd(0x3F, 16, 2); // Provides the I2C Bus address and defines the LCD as a 16 char,  2 line device
29double Input;            // declare Input to be a double variable  because the PID control library uses double (not interger) variables
30double Input2;
31double  Input3;
32double InputAve;    
33int RelayPin = 8;        // declare pin8 for  relay control
34int alert = 7;           // declare pin7 for alert control
35const  int tempMax = 320; // declare tempMax to be a constant 320 (degreeF)as the maximum  temperature the smoker can reach
36double tempSmoke = 0;    // declare tempSmoke  to be a double variable of the internal temp. of the smoker (DegF) read from thermocouple1
37int  tempMeat = 0;        // declare tempMeat to be an interger value of the internal  temp. of the meat being smoked (DegF) read from thermocouple2
38int tempMeat1 =  0;
39int tempMeat2 = 0;
40int tempMeatAve = 0;     // tempMeatAve is the average  of three tc2 readings to increase the accuracy of the actual meat temp reading
41int  keypress = 0;        // Set to 0 to eliminate any residual values from previous  cycles
42int keypress1 = 0;
43int keypress2 = 0;
44double Setpoint;         //  declare 'Setpoint' as the value entered from the keypad as the desired maximum internal  smoker temp.
45int SetMeatTemp;         // declare SetMeatTemp as the value entered  from the kaypad as the desired maximum internal meat temp.
46char Stop=0;             //  Sets the variable 'Stop' to zero to enable use of the 'while' function
47char Str1[15]  = "CYCLE COMPLETE";  // declare a character string variable to be used at the  end of the smoking cycle
48char Str2[15] = "ENJOY DINNER!!";  // declare a character  string variable to be used at the end of the smoking cycle
49double  Output;                    //Define  Variables we'll be connecting to for PID control
50int Input1=Input;        //  declare 'Input1' as an integer so the places past the decimal are dropped for the  Android (BT) display
51int Setpoint1=Setpoint;  // declare 'Setpoint1' as an integer  so the places past the decimal are dropped for the Android (BT) display
52PID myPID(&InputAve,  &Output, &Setpoint,150,1,1, DIRECT); //Specify the links and initial tuning parameters  for PID control
53int WindowSize = 3500;
54unsigned long windowStartTime;
55
56
57void  setup ()
58{
59  
60  Serial.begin(9600);
61  windowStartTime = millis();
62
63  myPID.SetOutputLimits(0, WindowSize);  //tell the PID to range between 0 and the  full window size
64  
65  myPID.SetMode(AUTOMATIC);              //activate the  PID
66  pinMode(RelayPin, OUTPUT);             //declare pin8 as an output to the  120v relay to turn power on or off to the heating coil
67  lcd.init();
68  lcd.backlight();
69  Wire.begin();
70  Keypad.SetHoldTime(100);
71  Keypad.Getkey();
72  lcd.begin(16,  2);
73  lcd.clear();           
74  pinMode(alert, OUTPUT);                //  declare pin7 as output for the alert
75  lcd.print("SMOKE TEMP?");              //Displays  'SMOKE TEMP?' on LCD
76                       
77  delay(100);                            //Allows  everything to get set
78}
79void loop()
80{ // The following section of the code  reads the desired temperature for the smoker and the meat and sets up a 3 digit  integer using
81  //  (int number = 100 * int1 + 10 * int2 + int3) for the variables  'Setpoint' and 'SetMeatTemp'.
82
83  // 1st digit of the desired smoker temperature:
84
85  while (Stop == 0) {   // Allows void loop to be executed in segments to control  when events happen. Without 'while' the ketpress is a random entry.
86    if ((Keypad.Key_State()  == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
87    {
88      lcd.setCursor(13,  0);
89
90      keypress = Keypad.Getkey();
91      while ((Keypad.Key_State()))  {} // Stay here until Key is held down
92      keypress = keypress - '0';
93      lcd.print(keypress);
94      Stop = 1;
95    }
96  }
97
98  //2nd digit smoke:
99  while (Stop ==  1) {
100    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released  = 2,  held = 3
101    {
102      lcd.setCursor(14, 0);
103      keypress1 = Keypad.Getkey();
104      while ((Keypad.Key_State())) {} // Stay here until Key is held down
105      keypress1  = keypress1 - '0';
106      lcd.print(keypress1);
107      Stop = 2;
108    }
109  }
110  //3rd digit smoke:
111  while (Stop == 2) {
112    if ((Keypad.Key_State()  == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
113    {
114      lcd.setCursor(15,  0);
115      keypress2 = Keypad.Getkey();
116      while ((Keypad.Key_State()))  {} // Stay here until Key is held down
117      keypress2 = keypress2 - '0';
118      lcd.print(keypress2);
119      Stop = 3;
120    }
121  }
122
123  while (Stop  == 3) {
124    Setpoint = 100 * keypress + 10 * keypress1 + keypress2; // Combines  the three entered digits into one (3 digit) variable called 'SetSmokeTemp'.
125
126    lcd.setCursor(0, 1);
127    delay(10);
128    lcd.print("MEAT TEMP?");                            //Displays  'MEAT TEMP' on LCD
129    Stop = 4;
130  }
131  // 1st digit of the desired meat  temperature:
132  while (Stop == 4) { // Allows void loop to be executed in segments  to control when events happen
133
134    if ((Keypad.Key_State() == 3))  // not  pressed = 0, pressed = 1, released = 2,  held = 3
135    {
136      lcd.setCursor(13,  1);
137      keypress = Keypad.Getkey();
138      while ((Keypad.Key_State())) {}  // Stay here until Key is held down
139      keypress = keypress - '0';
140      lcd.print(keypress);
141      Stop = 5;
142    }
143  }
144  //2nd digit meat:
145  while (Stop == 5) {
146    if ((Keypad.Key_State() == 3))  // not pressed = 0, pressed = 1, released =  2,  held = 3
147    {
148      lcd.setCursor(14, 1);
149      keypress1 = Keypad.Getkey();
150      while ((Keypad.Key_State())) {} // Stay here until Key is held down
151      keypress1  = keypress1 - '0';
152      lcd.print(keypress1);
153      Stop = 6;
154    }
155  }
156
157  //3rd digit meat:
158  while (Stop == 6) {
159    if ((Keypad.Key_State()  == 3))  // not pressed = 0, pressed = 1, released = 2,  held = 3
160    {
161      lcd.setCursor(15,  1);
162      keypress2 = Keypad.Getkey();
163      while ((Keypad.Key_State()))  {} // Stay here until Key is held down
164      keypress2 = keypress2 - '0';
165      SetMeatTemp = 100 * keypress + 10 * keypress1 + keypress2; //Combines the  3 entered digits into one (3 digit) variable called 'SetMeatTemp'.
166      lcd.print(keypress2);
167      Stop = 7;
168    }
169  }
170  
171  delay(50);                  // Provides  a delay before the cycle begins
172 
173  Input = (tc1.readF()-19);    //'Input'  is the reading of the actual internal smoker temperature adjusted(-19deg)to match  the Redi reading(at225deg)
174  delay(350);
175  
176  Input2=(tc1.readF()-19);
177  delay(350);
178  
179  Input3=(tc1.readF()-19);
180  delay(350);
181  
182  InputAve=(Input+Input2+Input3)/3;  //The average of 3 readings is a bit more accurate
183  
184  if (InputAve>335){InputAve=225;}  //Prevents a 'flier' from shutting down the program (max temp 320)
185  
186  delay(350);                 //the Max 6675 board is slow and should not be read more than 3  times per second
187  tempMeat = (tc2.readF()); //The reading from Thermocouple2  becomes the variable 'tempMeat' adjustment not needed to match the Redi reading(at165deg)
188  
189  delay(350);                 //the Max 6675 board is slow and should not be  read more than 3 times per second
190  tempMeat1 = (tc2.readF());
191  
192  delay(350);
193  tempMeat2 = (tc2.readF());
194 
195  delay(350);
196  if(tempMeat>tempMeat1+5||tempMeat<tempMeat1-5){tempMeat=100;tempMeat1=100;Serial.print("flier1  ");} //prevents 'fliers' from adversely affecting    //the program
197  if(tempMeat>tempMeat2+5||tempMeat<tempMeat2-5){tempMeat=100;tempMeat2=100;Serial.print("flier2");}  //prevents' fliers' from adversely affecting //the program
198  tempMeatAve =  (tempMeat+tempMeat1+tempMeat2)/3;                          //Accuracy improved by  averaging readings
199  
200  if(tempMeatAve>SetMeatTemp+10){tempMeatAve=150;Serial.print("flier3");}  //prevents 'fliers' from adversely affecting the program
201 
202
203                  //  The following 7 lines turns the output pin on/off based on PID output
204
205  myPID.Compute();  
206  
207  unsigned long now = millis();
208  
209  if(now - windowStartTime>WindowSize)
210  { 
211    windowStartTime += WindowSize;  //time to shift the Relay Window
212  }
213  if(Output > (now - windowStartTime)){ 
214   digitalWrite(RelayPin, HIGH);Serial.println("ON");  
215    }
216  else {digitalWrite(RelayPin,LOW);Serial.println("OFF");}//}
217                       
218    lcd.clear();                     // The following  17 lines set up the LCD display to indicate the Set & Actual temperatures
219    lcd.setCursor(0,  0);
220    lcd.print("SKset");
221    lcd.setCursor(5, 0);
222    lcd.print(Setpoint);
223    lcd.setCursor(9, 0);
224    lcd.print("ACT");
225    lcd.setCursor(13, 0);
226    lcd.print(InputAve);
227    lcd.setCursor(0, 1);
228    lcd.print("MTset");
229    lcd.setCursor(5, 1);
230    lcd.print(SetMeatTemp);
231    lcd.setCursor(9,  1);
232    lcd.print("ACT");
233    lcd.setCursor(13, 1);
234    lcd.print(tempMeatAve);
235    
236    Serial.print("SmokerSetTemp=");  // All "Serial.print" and "Serial.println"  commands are to send status of smoker to Android BT device
237    Setpoint1=Setpoint;
238    Serial.print(Setpoint1);
239    Serial.print("   ");
240    Serial.print("ActualTemp=");
241    Input1=InputAve;
242    Serial.print(Input1);             
243    Serial.println();
244    Serial.println();
245    Serial.print("MeatSetTemp  =  ");
246    Serial.print(SetMeatTemp);
247    Serial.print("   ");
248    Serial.print("ActualMeatTemp=");
249    Serial.print(tempMeatAve);
250    Serial.println();
251    Serial.println();
252    Serial.println(); 
253    Serial.println();
254    Serial.println();
255    Serial.println();
256    Serial.println();
257    Serial.println();
258    Serial.println();       
259    delay(50);
260    
261  if (InputAve>=tempMax)                       // The following 8 lines monitor the maximum temperature  of 320deg, shuts down the cycle, 
262    {digitalWrite(RelayPin, LOW);           //                                                          sends an alert to the  display, and buzzer
263                                           
264    lcd.clear();                            
265    lcd.setCursor(0,0); 
266    lcd.print("TEMPERATURE  OUT"); 
267    lcd.setCursor(0,1);
268    lcd.print(" OF CONTROL!!!");
269    digitalWrite(alert,  HIGH);}   
270  
271  if (tempMeatAve >= SetMeatTemp)            // When tempMeat(from  MAX6675(2)(thermocouple in meat))equals the meat set temp turn smoker coil OFF,
272                                             // indicate CYCLE COMPLETE on display,  sound the Alert, and stop the Smoker cycle
273  {
274    digitalWrite(RelayPin,  LOW);             //"Stops"the smoking cycle (until the meat temp drops below  the meat set temp)
275    Serial.println("                      DINNER IS READY");  //Sends message to Android BT device
276    Serial.println("                     COME  AND GET IT!");  //Sends message to Android BT device
277    Serial.println();
278    lcd.clear();
279    lcd.setCursor(0, 0);
280    lcd.print(Str1);                         //  print "CYCLE COMPLETE" on first line of LCD display
281    lcd.setCursor(0, 1);
282    lcd.print(Str2);                         // print "ENJOY DINNER!!" on second  line of LCD display
283    digitalWrite(alert, HIGH);               // Sets off  the alert buzzer 
284    delay(150);
285    digitalWrite(alert, LOW);                //  Provides a short 'beep-beep' instead of an annoying constant single'beeeeeeeep'
286    delay(150);
287    digitalWrite(alert, HIGH);
288    delay(150);
289    digitalWrite(alert,  LOW);
290    delay(3000);}
291    } 
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