Arduino I2C LCD Display Tutorial: Show Sensor Data on Screen

Introduction

Adding a 16×2 LCD display with an I2C module to your Arduino project lets you show real-time sensor readings without a computer. The I2C backpack reduces wiring from 12 wires to just 4 — making it one of the easiest display setups available.

Components Needed

• Arduino Uno
• 16×2 LCD with I2C backpack module
• DHT11 temperature sensor (optional)
• Jumper wires

Wiring (I2C)

Install the Library

In Arduino IDE go to Sketch > Include Library > Manage Libraries. Search for LiquidCrystal I2C by Frank de Brabander and install it.

Project 1: Hello World

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
void setup() {
  lcd.init(); lcd.backlight();
  lcd.setCursor(0, 0); lcd.print("Circuit of Things");
  lcd.setCursor(0, 1); lcd.print("Hello, Maker!");
}
void loop() {}

Project 2: Temperature Display with DHT11

#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#define DHTPIN 2
#define DHTTYPE DHT11
LiquidCrystal_I2C lcd(0x27, 16, 2);
DHT dht(DHTPIN, DHTTYPE);
void setup() {
  lcd.init(); lcd.backlight(); dht.begin();
}
void loop() {
  float t = dht.readTemperature();
  float h = dht.readHumidity();
  lcd.clear();
  lcd.setCursor(0,0); lcd.print("Temp: " + String(t,1) + " C");
  lcd.setCursor(0,1); lcd.print("Hum:  " + String(h,1) + " %");
  delay(2000);
}

Troubleshooting

• Blank screen? Adjust the contrast potentiometer on the I2C backpack.
• Wrong I2C address? Most modules use 0x27 or 0x3F. Use an I2C scanner sketch to find yours.

Conclusion

The I2C LCD is a fantastic way to add a user-friendly display to any Arduino project with minimal wiring complexity.