Creating a digital thermometer using Arduino is an excellent project for beginners and hobbyists interested in learning more about electronics and programming. This project involves using a temperature sensor to measure the ambient temperature and display the readings on an LCD screen. We will use an Arduino board, a temperature sensor (like the LM35 or DS18B20), and an LCD display for this project.

Components Required:

1. Arduino Uno or any compatible board
2. Temperature sensor (LM35 or DS18B20)
3. 16x2 LCD display
4. Breadboard and jumper wires
5. Potentiometer (10k ohm) for LCD contrast adjustment
6. Resistors (if needed for the specific sensor)

Step-by-Step Guide:

1. Connect the Temperature Sensor:

   • For LM35: Connect the VCC pin to 5V on the Arduino, the GND pin to GND, and the output pin to an analog pin (e.g., A0).
   • For DS18B20: Connect the VCC pin to 5V, the GND pin to GND, and the data pin to a digital pin (e.g., D2). Don't forget to add a pull-up resistor (4.7k ohm) between the data pin and VCC.

2. Connect the LCD Display:

   • Connect the pins of the LCD to the Arduino following the standard configuration:
     • VSS to GND
     • VDD to 5V
     • V0 to the middle pin of the potentiometer
     • RS to digital pin 7
     • RW to GND
     • E to digital pin 8
     • D4 to digital pin 9
     • D5 to digital pin 10
     • D6 to digital pin 11
     • D7 to digital pin 12
     • A (Anode) to 5V through a resistor
     • K (Cathode) to GND

3. Write the Arduino Code:

#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

const int sensorPin = A0; // Pin connected to the LM35 sensor
float temperature;

void setup() {
  lcd.begin(16, 2); // Set up the LCD's number of columns and rows
  lcd.print("Temp: "); // Print a message to the LCD
}

void loop() {
  int sensorValue = analogRead(sensorPin); // Read the sensor value
  temperature = (sensorValue * 5.0 * 100.0) / 1024.0; // Convert the analog reading to temperature

  lcd.setCursor(6, 0); // Set the cursor to column 6, line 0
  lcd.print(temperature); // Print the temperature
  lcd.print(" C");

  delay(1000); // Wait for a second before updating the reading
}

4. Upload the Code:

   • Connect your Arduino to your computer using a USB cable.
   • Open the Arduino IDE, paste the code, and upload it to your Arduino board.

5. Test Your Setup:

   • Once the code is uploaded, the LCD should display the current temperature in Celsius.

This project introduces basic concepts of interfacing sensors and displays with Arduino, which can be expanded into more complex systems such as weather stations or home automation systems.