#include <LiquidCrystal_I2C.h>

#define THERMISTOR_COUNT 10

const int THERMISTOR_PINS[THERMISTOR_COUNT] = {34, 35, 32, 33, 25, 26, 27, 14, 12, 13};
double Rth_values[THERMISTOR_COUNT];
double temperature_values[THERMISTOR_COUNT];

const double VCC = 3.3;             // NodeMCU on board 3.3v vcc
const double R2 = 10000;            // 10k ohm series resistor
const double adc_resolution = 4096; // 12-bit adc

const double A = 0.001129148;   // thermistor equation parameters
const double B = 0.000234125;
const double C = 0.0000000876741; 

void setup() {
  Serial.begin(9600);  /* Define baud rate for serial communication */

  lcd.begin(16, 2);
  lcd.print("Temperature:");
}

void loop() {
  for (int i = 0; i < THERMISTOR_COUNT; i++) {
    double Vout, Rth, temperature, adc_value; 

    adc_value = adc_resolution - analogRead(THERMISTOR_PINS[i]) + 0.5; // switch direction
    Vout = (adc_value * VCC) / adc_resolution; 
    Rth = (VCC * R2 / Vout) - R2; // Formula for R2 as Pull-down: Vcc-Rth-R2-GND

    /* Steinhart-Hart Thermistor Equation:
     * Temperature in Kelvin = 1 / (A + B[ln(R)] + C[ln(R)]^3)
     */
    temperature = 1 / (A + (B * log(Rth)) + (C * pow(log(Rth), 3)));   // Temperature in kelvin
    temperature = temperature - 273.15;  // Temperature in degree Celsius

    Rth_values[i] = Rth;
    temperature_values[i] = temperature;


    lcd.setCursor(0, i);
    lcd.print("Thermistor ");
    lcd.print(i + 1);
    lcd.print(": ");
    lcd.print(temperature_values[i]);
    lcd.print(" C   ");

    Serial.print("Thermistor ");
    Serial.print(i + 1);
    Serial.print(": Rth = ");
    Serial.print(Rth_values[i]);
    Serial.print(", Temperature = ");
    Serial.print(temperature_values[i]);
    Serial.println(" degree Celsius");
  }

  delay(50000);
}