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// library for PID
#include <PID_v1.h>

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
 
//float   gain = 0.00488; // Termocouple anv. ej
//float   ref  = 1.25313; // Termocouple anv. ej

const int GreenLED = 8; 
const int RedLED = 2; 

const int thermocouplePin = A0;  //Termistor anv ist. 
int iSetpoint;
int tempResistor;
int Vo; // Holds the ADC Value
float R2, tKelvin, tCelsius, tFahrenheit;
const float Beta     = 3974.0;
const float roomTemp = 298.15;   // room temperature in Kelvin (25 grader C)
const float Ro = 100000.0; // Resistance of the thermistor at roomTemp
const float R1 = 100300.0;  // Resistnce of the known resistor

  
const int potPin = A1; // Potentiometer input pin
const int ovenPin = 6; // LED output pin

// Tuning parameters
float Kp = 0; // Proportional gain
float Ki = 0.5; // Integral gain
float Kd = 0; // Differential gain
// Record the set point as well as the controller input(y) and output(u)
double Setpoint, y, u;
// Create a controller that is linked to the specified Input, Ouput and Setpoint
PID myPID(&y, &u, &Setpoint, Kp, Ki, Kd, DIRECT);
const int sampleRate = 1; // Time interval of the PID control

void setup(){ 
  //setup serial at 9600 bps
  Serial.begin(9600);
   //setup LEDs as output
  pinMode(GreenLED, OUTPUT);
    pinMode(RedLED, OUTPUT);

  myPID.SetMode(AUTOMATIC);     // Turn on the PID control
  myPID.SetSampleTime(sampleRate); // Assign the sample rate of the control

   display.begin(SSD1306_SWITCHCAPVCC,0x3C); //OLED address 
  display.clearDisplay();
}
 
void loop(){

  //-------PID Controller-------
  Setpoint = map(analogRead(potPin), 0, 1023, 0, 255); // read and scale the set point
  // read the temperature input convert to Celsius degree
  //y = (double(analogRead(thermocouplePin)) * gain - ref)/0.005; // Termocouple anv. ej
 // rutin för Termistor
   Vo = analogRead(thermocouplePin); //eg Termistorpin
   R2 = R1 * (1023.0 / (float)Vo - 1.0); // Resistance of the Thermistor
   tKelvin = (Beta * roomTemp) /(Beta + (roomTemp * log(R2 / Ro)));
   tCelsius = tKelvin - 273.15;
   y=tCelsius;
   tempResistor = y;
   iSetpoint=Setpoint;
 

  myPID.Compute(); // Calculates the PID output at a specified sample time
  analogWrite(ovenPin, u); // Send output to oven

  //Turn on LEDs according to whether the temperature is within range
  if(tempResistor == iSetpoint){
    digitalWrite(RedLED, LOW);
        digitalWrite(GreenLED, HIGH);
  }
  
  if(tempResistor > iSetpoint){
    digitalWrite(RedLED, LOW);
        digitalWrite(GreenLED, HIGH);
  }
  else{
    digitalWrite(RedLED, HIGH);
    digitalWrite(GreenLED, LOW);
  }

  //Display on Serial Monitor
  Serial.print("Temperature: ");
  Serial.print(y);
  Serial.print("°C, "); 

  Serial.print("Setpoint:");
  Serial.print(Setpoint);
  Serial.print(", ");

    Serial.print("Output:");
  Serial.println(u);

  // The tuning parameters can be retrieved by the Arduino from the serial monitor: eg: 0,0.5,0 with Ki set to 0.5.
   // Commas are ignored by the Serial.parseFloat() command
      if (Serial.available() > 0){
        for (int i = 0; i < 4; i++){
          switch(i){
          case 0:
          Kp = Serial.parseFloat();
          break;
          case 1:
          Ki = Serial.parseFloat();
          break;
          case 2:
          Kd = Serial.parseFloat();
          break;
          case 3:
            for (int j = Serial.available(); j == 0; j--){
            Serial.read();
            }
          break;
          }
        }
      Serial.print(" Kp,Ki,Kd = "); // Display the new parameters
      Serial.print(Kp);
      Serial.print(",");
      Serial.print(Ki);
      Serial.print(",");
      Serial.print(Kd);
      Serial.println();
      myPID.SetTunings(Kp, Ki, Kd); // Set the tuning of the PID loop
      }
  
//  Display ändra till oled
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(108, 0);
  display.println("C"); 
  display.setCursor(108, 22);
  display.println("C");   
  display.setTextSize(2);
  //display.setTextColor(WHITE);
   display.setCursor(0, 0);
  display.println("Bed");
  display.setCursor(55, 0);
  display.println(tempResistor);
  display.setCursor(0, 22);
  display.println("SetP");
  display.setCursor(55, 22);
  display.println(iSetpoint);
  display.setCursor(0, 44);
  display.println("Outp");
  display.setCursor(55, 44);
  display.println(u);
  
  display.display();

  delay(100); // wait a bit
    
}