// LCD pin layout
// RS  -> Arduino digital pin 7
// E   -> Arduino digital pin 6
// D4  -> Arduino digital pin 5
// D5  -> Arduino digital pin 4
// D6  -> Arduino digital pin 3
// D7  -> Arduino digital pin 2

#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);

const int SENSOR_PIN = A0;
const int RELAY_PIN = 8;
const int POT_PIN = A1;

float tempC;
float setTemp;

void setup() {
  pinMode(RELAY_PIN, OUTPUT);
  lcd.begin(20, 4);
  lcd.print("Temp Controller");
}

void loop() {
  setTemp = map(analogRead(POT_PIN), 0, 1023, 0, 100); // Map potentiometer value from 0-1023 to 0-100
  tempC = 1 / (log(1 / (1023. / analogRead(SENSOR_PIN) - 1)) / 3950.0 + 1.0 / 298.15) - 273.15;

  lcd.setCursor(0, 1);
  lcd.print("Temp: ");
  lcd.print(tempC);
  lcd.print("C");
  lcd.setCursor(0, 2);
  lcd.print("Set Temp: ");
  lcd.print(setTemp);
  lcd.print("C");

  if (tempC < setTemp) {
    digitalWrite(RELAY_PIN, HIGH); // turn on relay
  } else {
    digitalWrite(RELAY_PIN, LOW); // turn off relay
  }

  delay(1000);
}