Thermistor thermometer on an LCD (pins 7 to 12), on an Arduino Uno

// Thermometer: a thermistor on A0, the temperature on a 16x2 LCD.
//
//   5V -> thermistor -> A0 -> 10k resistor -> GND
//   LCD RS -> 7, E -> 8, D4 -> 9, D5 -> 10, D6 -> 11, D7 -> 12
//   LCD RW, VSS, K, V0 -> GND     LCD VDD, A -> 5V
//
// A thermistor's resistance falls as it warms. With it on top of a 10k
// resistor, A0 reads more when it is warm and less when it is cold. From the
// reading the sketch works out the thermistor's resistance:
//
//   R = 10000 * (1023 / reading - 1)
//
// and the beta equation turns that into kelvin, using the part's two numbers
// from its datasheet: 10k at 25 C, and a beta of 3950.
//
// Click the thermistor and drag its temperature to watch the display follow.

#include <LiquidCrystal.h>
#include <math.h>

const int SENSOR = A0;
const float BETA = 3950.0;
const float R25 = 10000.0;
const float T25 = 298.15;  // 25 C in kelvin

LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

void setup() {
  lcd.begin(16, 2);
  Serial.begin(9600);
  Serial.println("Mokxi Uno: thermistor on A0, LCD on pins 7 to 12");
}

void loop() {
  int reading = analogRead(SENSOR);
  if (reading < 1) reading = 1;
  if (reading > 1022) reading = 1022;
  float resistance = R25 * (1023.0 / reading - 1.0);
  float kelvin = 1.0 / (1.0 / T25 + log(resistance / R25) / BETA);
  float celsius = kelvin - 273.15;
  float fahrenheit = celsius * 9.0 / 5.0 + 32.0;

  lcd.setCursor(0, 0);
  lcd.print("Temp     C  ");
  lcd.setCursor(6, 0);
  lcd.print(celsius, 1);
  lcd.setCursor(0, 1);
  lcd.print("Temp     F  ");
  lcd.setCursor(6, 1);
  lcd.print(fahrenheit, 1);

  Serial.print(celsius, 1);
  Serial.println(" C");
  delay(500);
}