#include <PID_v1.h>
#include <LiquidCrystal_I2C.h>
#include "DHT.h"
 #define DHTTYPE DHT22 
#define DHTPIN 29 // Digital pin connected to the DHT sensor

DHT dht(DHTPIN, DHTTYPE);
#include <Keypad.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);

//KEYPAD
const int ROW_NUM = 4; //four rows
const int COLUMN_NUM = 4; //four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1','2','3', 'A'},
  {'4','5','6', 'B'},
  {'7','8','9', 'C'},
  {'*','0','#', 'D'}
};

byte pin_rows[ROW_NUM] = {35, 37, 39, 41}; //connect to the row pinouts of the keypad
byte pin_column[COLUMN_NUM] = {43, 45, 47, 49}; //connect to the column pinouts of the keypad

Keypad keypad = Keypad( makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );

String inNUM;
//long inSetpoint;

#define ssr 3
#define FANHEAT 6
//#define FANEX 7
//Variables
float temperature_read = 0.0;
float set_temperature = 0;
float PID_error = 0;
float previous_error = 0;
float elapsedTime, Time, timePrev;
int PID_value = 0;



//PID constants
int kp = 90;   int ki = 0.3;   int kd = 1.8;
int PID_p = 0;    int PID_i = 0;    int PID_d = 0;

void setup()
{
  
  Serial.begin(9600);  
  dht.begin(); 
   inNUM.reserve(10); // maximum number of digit for a number is 10, change if needed
  //SetLCD
  lcd.init();
  lcd.backlight();
  
}
 
void loop(){
 float h = dht.readHumidity();
// Read temperature as Celsius (the default)
float TempC = dht.readTemperature();
//Serial.print(F("Humidity: "));
//Serial.print(h);
lcd.setCursor(0, 3);
lcd.print("HUMI ");
  lcd.print(h);
lcd.setCursor(10, 3);
lcd.print("TEMP ");
  lcd.print(TempC);
//Serial.print(F("% Temperature: "));
//Serial.print(t); 
lcd.setCursor(0, 1);
lcd.print("Setpoint ");
  lcd.print(set_temperature);
  //Inputset Section
   char key = keypad.getKey();

  if (key) {
    //Serial.println(key);

    if (key >= '0' && key <= '9') {     // only act on numeric keys
      inNUM += key;               // append new character to input string
  
    } else if (key == '#') {
      if (inNUM.length() > 0) {
        set_temperature = inNUM.toInt(); // YOU GOT AN INTEGER NUMBER
        inNUM = "";               // clear input
        // DO YOUR WORK HERE

      }
    } else if (key == '*') {
      inNUM = "";                 // clear input
    
    }
    lcd.clear();
  
  }
  lcd.setCursor(0, 0);
      lcd.print("Enter Set ");
      lcd.print(inNUM);

   // First we read the real value of temperature
    temperature_read = TempC;
  //Next we calculate the error between the setpoint and the real value
  PID_error = set_temperature - TempC;
  //Calculate the P value
  PID_p = kp * PID_error;
  //Calculate the I value in a range on +-3
  if(-3 < PID_error <3)
  {
    PID_i = PID_i + (ki * PID_error);
  }

  //For derivative we need real time to calculate speed change rate
  timePrev = Time;                            // the previous time is stored before the actual time read
  Time = millis();                            // actual time read
  elapsedTime = (Time - timePrev) / 1000; 
  //Now we can calculate the D calue
  PID_d = kd*((PID_error - previous_error)/elapsedTime);
  //Final total PID value is the sum of P + I + D
  PID_value = PID_p + PID_i + PID_d;

  //We define PWM range between 0 and 255
  if(PID_value < 0)
  {    PID_value = 255;    }
  if(PID_value > 255)  
  {    PID_value = 0;  }

  //if((set_temperature <= 30) || (set_temperature >= 61) )  
  //{    analogWrite(ssr,0);  }
  //if((set_temperature >= 31) || (set_temperature <= 60) )  
  //{    analogWrite(ssr,255-PID_value);  }
  //Now we can write the PWM signal to the mosfet on digital pin D3
  
  analogWrite(ssr,255-PID_value);
  previous_error = PID_error;     //Remember to store the previous error for next loop.
 
  Serial.print(ssr);
  Serial.print(" ");
  Serial.println(PID_value);
  Serial.print(" ");  
  Serial.println(set_temperature);
 //delay(200); 
}