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Arduino - LCD 20x4

In this Arduino LCD 20x4 I2C tutorial, we will learn how to connect an LCD 20x4 (Liquid Crystal Display) to the Arduino board via I2C Interface.

Hardware Required

1	×	Arduino UNO or Genuino UNO
1	×	USB 2.0 cable type A/B
1	×	LCD 20x4
1	×	Jumper Wires
1	×	(Optional) 9V Power Adapter for Arduino
1	×	(Recommended) Screw Terminal Block Shield for Arduino Uno

Or you can buy the following sensor kit:

DIYables Sensor Kit 30 types, 69 units

Please note: These are Amazon affiliate links. If you buy the components through these links, We will get a commission at no extra cost to you. We appreciate it.

About LCD I2C 16x2

Pinout

LCD 20x4 I2C uses I2C interface, so it has 4 pins:

GND pin: needs to be connected to GND (0V).
VCC pin: the power supply for the LCD, needs to be connected to VCC (5V).
SDA pin: I2C data signal
SCL pin: I2C clock signal

LCD Coordinate

LCD I2C 16x2 includes 20 columns and 4 rows. the conlums and rows are indexed from 0.

Wiring Diagram

This image is created using Fritzing. Click to enlarge image

LCD I2C	Arduino Uno, Nano	Arduino Mega
Vin	5V	5V
GND	GND	GND
SDA	A4	20
SCL	A5	21

How To Program For LCD I2C

Thanks to the LiquidCrystal_I2C library, the using LCD is a piece of cake.

Include the library:

#include <LiquidCrystal_I2C.h> // Library for LCD

Declare a LiquidCrystal_I2C object with I2C address, the number of columns, the number of rows:

LiquidCrystal_I2C lcd(0x27, 20, 4); // I2C address 0x27, 20 column and 4 rows

Initialize the LCD.

lcd.init(); //initialize the lcd lcd.backlight(); //open the backlight

Move cursor to the desired position (column_index, row_index)

lcd.setCursor(column_index, row_index);

Print a message to the LCD.

lcd.print("Hello World!");

※ NOTE THAT:

The I2C address of LCD can vary according to the manufacturers. In the code, we used 0x27 that is specified by DIYables manufacturer

Arduino Code

/* * Created by ArduinoGetStarted.com * * This example code is in the public domain * * Tutorial page: https://arduinogetstarted.com/tutorials/arduino-lcd-20x4 */ #include <LiquidCrystal_I2C.h> LiquidCrystal_I2C lcd(0x27, 20, 4); // I2C address 0x27, 20 column and 4 rows void setup() { lcd.init(); // initialize the lcd lcd.backlight(); lcd.setCursor(0, 0); // move cursor the first row lcd.print("LCD 20x4"); // print message at the first row lcd.setCursor(0, 1); // move cursor to the second row lcd.print("I2C Address: 0x27"); // print message at the second row lcd.setCursor(0, 2); // move cursor to the third row lcd.print("DIYables"); // print message at the third row lcd.setCursor(0, 3); // move cursor to the fourth row lcd.print("www.diyables.io"); // print message the fourth row } void loop() { }

Quick Steps

On Arduino IDE, Go to Tools Manage Libraries

Search "LiquidCrystal I2C", then find the LiquidCrystal_I2C library by Frank de Brabander
Click Install button to install LiquidCrystal_I2C library.

Copy the above code and open with Arduino IDE
Click Upload button on Arduino IDE to upload code to Arduino
See the result on LCD

Try modifying text and position

Video Tutorial

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