#include <EEPROM.h>
#define potentiometer  A5

int Vo;
float R1 = 10000;
float logR2, R2, T, Tc;
float c1 = 1.009249522e-03, c2 = 2.378405444e-04, c3 = 2.019202697e-07;

int Aux = 5;
int Tv = 6;
int Dvd = 7;
int Usb = 8;
int pin_switch = 2;
int relay = 12;
byte relayState = 0;
int read_pot = 0;

unsigned long currentMillis;
unsigned long previousMillis;
unsigned long duration;

int tempPin = A1;   // the output pin of LM35
int fan = 3;       // the pin where fan is
int led = 4 ;        // led pin
int temp;
int tempMin = 40;   // the temperature to start the fan
int tempMax = 70;   // the maximum temperature when fan is at 100%
int fanSpeed;
//int ledState;
boolean oldSwitchState = LOW;
boolean newSwitchState = LOW;
byte state = 0;

void setup()
{
 
  delay(2000);
   Serial.begin(9600);
  pinMode(Aux, OUTPUT);
  digitalWrite(Aux, LOW);
  pinMode(Tv, OUTPUT);
  digitalWrite(Tv, LOW);
  pinMode(Dvd, OUTPUT);
  digitalWrite(Dvd, LOW);
  pinMode(Usb, OUTPUT);
  digitalWrite(Usb, LOW);
  pinMode(pin_switch, INPUT);
  attachInterrupt(digitalPinToInterrupt(pin_switch), Switch, HIGH);
  checkLedState();
  pinMode(fan, OUTPUT);
  pinMode(led, OUTPUT);
  pinMode(tempPin, INPUT);
  pinMode(potentiometer, INPUT);
  pinMode(relay, OUTPUT);
  digitalWrite(relay, LOW);
  //LedState();
}

void Switch()
{
  newSwitchState = digitalRead(pin_switch);
  if ( newSwitchState != oldSwitchState )
  {
    // has the button switch been closed?
    if ( newSwitchState == HIGH )
    {
      // increase the value of state
      state++;
     // delay(1000);
      if (state > 4) {
        state = 1;
      }
      //digitalWrite(Aux, LOW);
      //  digitalWrite(Tv, LOW);
      // digitalWrite(Dvd, LOW);
      //  digitalWrite(Usb, LOW);
      delay(1000);
      LedState();
      delay(1000);

    }
    oldSwitchState = newSwitchState;
    EEPROM.update(0, state);
    delay(200);
  }
}
void loop() {
  relayTime();
  fanControl();
  LedState();
}

void checkLedState() {
  state = EEPROM.read(0);
  LedState();
}
void LedState() {
  if (state == 1) {
    digitalWrite(Aux, HIGH);
    digitalWrite(Tv, LOW);
    digitalWrite(Dvd, LOW);
    digitalWrite(Usb, LOW);
  }
  if (state == 2) {
    digitalWrite(Aux, LOW);
    digitalWrite(Tv, HIGH);
    digitalWrite(Dvd, LOW);
    digitalWrite(Usb, LOW);
  }
  if (state == 3) {
    digitalWrite(Aux, LOW);
    digitalWrite(Tv, LOW);
    digitalWrite(Dvd, HIGH);
    digitalWrite(Usb, LOW);
  }
  if (state == 4) {
    digitalWrite(Aux, LOW);
    digitalWrite(Tv, LOW);
    digitalWrite(Dvd, LOW);
    digitalWrite(Usb, HIGH);
  }
}

void fanControl()
{
  temp = readTemp();
  Serial.print("Temperature: ");
  Serial.println(temp);// get the temperature
  if (temp  < tempMin) { // if temp is lower than minimum temp
    fanSpeed = 0; // fan is not spinning
    digitalWrite(fan, LOW);
  }
  if ((temp  >= tempMin) && (temp <=tempMax)) { // if temperature is higher than minimum temp
    fanSpeed = map(temp, tempMin, tempMax, 32, 255); // the actual speed of fan

    analogWrite(fan, fanSpeed); // spin the fan at the fanSpeed speed
  }
  if (temp  > tempMax) {       // if temp is higher than tempMax
    digitalWrite(led, HIGH);  // turn on led
  } else {                    // else turn of led
    digitalWrite(led, LOW);
  }
  delay(200);
}

/*int readTemp() {  // get the temperature and convert it to celsius
  temp = analogRead(tempPin);
  return temp * 0.48828125;
  }*/
int readTemp() {
  Vo = analogRead(tempPin);
  R2 = R1 * (1023.0 / (float)Vo - 1.0);
  logR2 = log(R2);
  T = (1.0 / (c1 + c2 * logR2 + c3 * logR2 * logR2 * logR2));
  Tc = T - 273.15;
  temp = Tc;
  // delay(200);
  return temp*2.5 ;
//  return temp * 1;
 
}

void relayTime()
{
  read_pot = analogRead(potentiometer);
  duration = map(read_pot, 0, 1023, 300UL, 30000UL);
  currentMillis = millis();
  if ((currentMillis - previousMillis) > duration)
  {
    previousMillis = previousMillis + duration;
    relayState = 1 ;
    digitalWrite(relay, relayState);
  }

}