Connect a Hitachi LCD Display to Arduino via I2C Bus

What is an I2C LCD Controller?

An I2C LCD controller allows you to control an LCD display using only two wires (SDA and SCL). It is an efficient alternative to directly controlling an LCD, which would otherwise require many pins from Arduino.

This controller is based on the PCF8574 I/O expander and includes a potentiometer to adjust the backlight.

Price

An I2C controller costs around €0.60, while an LCD display (16×2) costs €1.70 when purchased together. Larger LCDs (20×4) cost about €4.20.

Mounting Scheme

The connection is simple. Power the module with 5V and GND from Arduino, and connect the SDA and SCL pins:

• SDA: A4 (Arduino Uno/Nano)
• SCL: A5 (Arduino Uno/Nano)

Code Examples

Basic Example

The following code initializes the LCD and displays "Line 1" and "Line 2" on a 16×2 screen:

#include  
#include 

LiquidCrystal_I2C lcd(0x27, 16, 2);  // LCD at address 0x27, 16x2

void setup() {
    lcd.begin();                       // Initialize the LCD
    lcd.backlight();                   // Turn on the backlight
    lcd.setCursor(0, 0);               // Set cursor to the first line
    lcd.print("Line 1");               // Display "Line 1"
    lcd.setCursor(0, 1);               // Set cursor to the second line
    lcd.print("Line 2");               // Display "Line 2"
    delay(2500);                       // Wait for 2.5 seconds
    lcd.clear();                       // Clear the display
}

void loop() {
    // No additional actions in the loop
}