Arduino Temperature Display V1

#include <OneWire.h>                       // library to access DS18B20
#include <DallasTemperature.h>             // library to support DS18B20
#include <Wire.h>                          // library for communicating to I2C devices
#include <hd44780.h>                       // main hd44780 library
#include <hd44780ioClass/hd44780_I2Cexp.h> // i2c expander i/o class library

hd44780_I2Cexp lcd; // declare lcd object: auto locate & auto configure expander chip

OneWire oneWire(2); // tell the library to use the digital pin the DS18B20 is connected to

DallasTemperature sensors(&oneWire); // tell the library to compute temp on the oneWire pin

int IOL; // initialize the LDR pin name as a 16-bit value

void setup() {
  Serial.begin(9600); // setup Serial for debug
  sensors.begin(); // start DS18B20
  IOL = analogRead(A0); // initialize LDR as analog pin 0 - read only
  lcd.begin(16, 2); // initialize lcd as 16 columns, 2 rows
  lcd.clear(); // clear any old data on the lcd
  // if there is lots of ambient light, turn on the lcd backlight
  if (IOL < 500) {
    lcd.backlight();
  }
  // if the ambient light is low, turn off the backlight
  if (IOL >= 500) {
    lcd.noBacklight();
  }
}

void loop() {
  IOL = analogRead(A0); // initialize LDR as analog pin 0 - read only
  // if there is lots of ambient light, turn on the lcd backlight
  if (IOL < 500) {
    lcd.backlight();
  }
  // if the ambient light is low, turn off the backlight
  if (IOL >= 500) {
    lcd.noBacklight();
  }

  sensors.requestTemperatures(); // send data asking for temperature to DS18B20
  lcd.setCursor(0, 0); // set the lcd cursor for celsius temperature
  lcd.print("Temp C: "); // print explanation of following data
  lcd.print(sensors.getTempCByIndex(0)); // print the degrees in celsius
  lcd.print("       "); // print spaces to blank out any remanants of data
  lcd.setCursor(0, 1); // set the lcd for farenheit temperature
  lcd.print("Temp F: "); // print explanation of following data
  lcd.print(DallasTemperature::toFahrenheit(sensors.getTempCByIndex(0))); // Convert tempC to Fahrenheit and print it
  lcd.print("       "); // print spaces to blank out any remanants of data

/*
  sensors.requestTemperatures(); // send data asking for temperature to DS18B20
  lcd.setCursor(0, 0); // set the lcd cursor for celsius temperature
  lcd.print(F("Temp: ")); // print explanation of following data from program storage
  lcd.print(sensors.getTempCByIndex(0)); // print the degrees in celsius
  lcd.print(F(" ")); // print space from program storage
  lcd.print((char)223); // print degrees symbol
  lcd.print(F("C")); // print celsius abbreviation
  lcd.print("       "); // print spaces to blank out any remanants of data
  lcd.setCursor(0, 1); // set the lcd for light levels
  lcd.print(F("Light Level: ")); // print explanation of following data
  lcd.print(IOL); // print light levels
  lcd.print("       "); // print spaces to blank out any remanants of data
*/
}