int rs = 7;
int en = 8;
int d4 = 9;
int d5 = 10;
int d6 = 11;
int d7 = 12;
int sensorPin = 2;
void sendCommand(byte command) {

  digitalWrite(rs, LOW);

  // Send first 4 bits
  digitalWrite(d4, (command >> 4) & 1);
  digitalWrite(d5, (command >> 5) & 1);
  digitalWrite(d6, (command >> 6) & 1);
  digitalWrite(d7, (command >> 7) & 1);

  digitalWrite(en, HIGH);
  delayMicroseconds(1);
  digitalWrite(en, LOW);

  // Send remaining 4 bits
  digitalWrite(d4, command & 1);
  digitalWrite(d5, (command >> 1) & 1);
  digitalWrite(d6, (command >> 2) & 1);
  digitalWrite(d7, (command >> 3) & 1);

  digitalWrite(en, HIGH);
  delayMicroseconds(1);
  digitalWrite(en, LOW);

  delay(2);
}


// LCD DATA FUNCTION
void sendData(byte data) {

  digitalWrite(rs, HIGH);

  // Send first 4 bits
  digitalWrite(d4, (data >> 4) & 1);
  digitalWrite(d5, (data >> 5) & 1);
  digitalWrite(d6, (data >> 6) & 1);
  digitalWrite(d7, (data >> 7) & 1);

  digitalWrite(en, HIGH);
  delayMicroseconds(1);
  digitalWrite(en, LOW);

  // Send remaining 4 bits
  digitalWrite(d4, data & 1);
  digitalWrite(d5, (data >> 1) & 1);
  digitalWrite(d6, (data >> 2) & 1);
  digitalWrite(d7, (data >> 3) & 1);

  digitalWrite(en, HIGH);
  delayMicroseconds(1);
  digitalWrite(en, LOW);

  delayMicroseconds(50);
}


// PRINT TEXT ON LCD
void printText(char text[]) {

  int i = 0;

  while (text[i] != '\0') {
    sendData(text[i]);
    i++;
  }
}


// DS18B20 RESET
bool resetSensor() {

  pinMode(sensorPin, OUTPUT);
  digitalWrite(sensorPin, LOW);
  delayMicroseconds(480);

  pinMode(sensorPin, INPUT);
  delayMicroseconds(70);

  bool presence = (digitalRead(sensorPin) == LOW);

  delayMicroseconds(410);

  return presence;
}


// WRITE ONE BIT
void writeBit(byte value) {

  pinMode(sensorPin, OUTPUT);
  digitalWrite(sensorPin, LOW);

  if (value == 1) {
    delayMicroseconds(6);
    pinMode(sensorPin, INPUT);
    delayMicroseconds(64);
  }

  else {
    delayMicroseconds(60);
    pinMode(sensorPin, INPUT);
    delayMicroseconds(10);
  }
}


// WRITE ONE BYTE
void writeByte(byte value) {

  for (int i = 0; i < 8; i++) {
    writeBit(value & 1);
    value = value >> 1;
  }
}


// READ ONE BIT
byte readBit() {

  byte value;

  pinMode(sensorPin, OUTPUT);
  digitalWrite(sensorPin, LOW);
  delayMicroseconds(6);

  pinMode(sensorPin, INPUT);
  delayMicroseconds(9);

  value = digitalRead(sensorPin);

  delayMicroseconds(55);

  return value;
}


// READ ONE BYTE
byte readByte() {

  byte value = 0;

  for (int i = 0; i < 8; i++) {

    if (readBit() == HIGH) {
      value = value | (1 << i);
    }
  }

  return value;
}


// ---------------- SETUP ----------------

void setup() {

  // LCD pins
  pinMode(rs, OUTPUT);
  pinMode(en, OUTPUT);
  pinMode(d4, OUTPUT);
  pinMode(d5, OUTPUT);
  pinMode(d6, OUTPUT);
  pinMode(d7, OUTPUT);

  // Initialize LCD
  delay(50);

  sendCommand(0x33);
  sendCommand(0x32);
  sendCommand(0x28);
  sendCommand(0x0C);
  sendCommand(0x06);
  sendCommand(0x01);
}


// ---------------- LOOP ----------------

void loop() {

  // Reset DS18B20
  if (resetSensor()) {

    // Skip ROM
    writeByte(0xCC);

    // Start temperature conversion
    writeByte(0x44);

    // Wait for conversion
    delay(750);


    // Reset sensor again
    resetSensor();

    // Skip ROM
    writeByte(0xCC);

    // Read scratchpad
    writeByte(0xBE);


    // Read temperature data
    byte lowByte = readByte();
    byte highByte = readByte();


    // Combine bytes
    int rawTemperature = (highByte << 8) | lowByte;

    // Convert to Celsius
    float temperature = rawTemperature / 16.0;


    // Clear LCD
    sendCommand(0x01);


    // First row
    sendCommand(0x80);
    printText("Temperature:");


    // Second row
    sendCommand(0xC0);


    // Convert temperature to integer
    int temp = (int)temperature;


    // Display hundreds digit
    if (temp >= 100) {
      sendData((temp / 100) + '0');
    }

    // Display tens digit
    if (temp >= 10) {
      sendData(((temp / 10) % 10) + '0');
    }

    // Display ones digit
    sendData((temp % 10) + '0');

    printText(" C");
  }

  delay(500);
}