Arduino UNO R4 - LCD 20x4
In this tutorial, we will show you how to use a 20x4 LCD display with Arduino UNO R4 board using an I2C interface. In detail, We will learn:
- How to connect LCD I2C 20x4 to Arduino UNO R4
- How to program Arduino UNO R4 to display information on LCD I2C 20x4
Hardware Preparation
Or you can buy the following sensor kits:
| 1 | × | DIYables Sensor Kit (30 sensors/displays) | |
| 1 | × | DIYables Sensor Kit (18 sensors/displays) |
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Overview of LCD I2C 20x4
Pinout
The LCD 20x4 I2C uses the I2C interface and has 4 pins:
- GND pin: connect it to GND (0V).
- VCC pin: connect to VCC (5V) to power the LCD.
- SDA pin: this is for I2C data signal.
- SCL pin: this is for I2C clock signal.
LCD Coordinate
The LCD I2C 20x4 has 20 columns and 4 rows. The columns and rows start from 0.
Wiring Diagram
This image is created using Fritzing. Click to enlarge image
| LCD I2C | Arduino UNO R4, Nano | Arduino Mega |
|---|---|---|
| Vin | 5V | 5V |
| GND | GND | GND |
| SDA | A4 | 20 |
| SCL | A5 | 21 |
How To Program For LCD I2C
Using the LCD is very easy with the LiquidCrystal_I2C library.
- Add the library:
#include <LiquidCrystal_I2C.h>
- Create a LiquidCrystal_I2C object with the I2C address, number of columns, and number of rows:
LiquidCrystal_I2C lcd(0x27, 20, 4); // Initialize LCD with I2C address 0x27, 20 columns, and 4 rows
- Set up the LCD screen.
lcd.init(); // Initialize the LCD display
lcd.backlight(); // Turn on the backlight of the LCD
- Place the cursor at the specific position given by column_index and row_index.
lcd.setCursor(column_index, row_index);
- Display a message on the LCD screen.
lcd.print("Hello World!");
※ NOTE THAT:
Different manufacturers may use different I2C addresses for the LCD. In our example, we used the address 0x27 as given by the manufacturer DIYables.
Arduino UNO R4 Code
/*
* This Arduino UNO R4 code was developed by newbiely.com
*
* This Arduino UNO R4 code is made available for public use without any restriction
*
* For comprehensive instructions and wiring diagrams, please visit:
* https://newbiely.com/tutorials/arduino-uno-r4/arduino-uno-r4-lcd-20x4
*/
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4); // Initial setup for a 20 columns x 4 rows LCD with I2C address 0x27
void setup() {
lcd.init(); // Initialize the LCD
lcd.backlight(); // Turn on the backlight
lcd.setCursor(0, 0); // Position cursor at the first row, first column
lcd.print("LCD 20x4"); // Display text at the first row
lcd.setCursor(0, 1); // Position cursor at the second row, first column
lcd.print("I2C Address: 0x27"); // Display text at the second row
lcd.setCursor(0, 2); // Position cursor at the third row, first column
lcd.print("DIYables"); // Display text at the third row
lcd.setCursor(0, 3); // Position cursor at the fourth row, first column
lcd.print("www.diyables.io"); // Display text at the fourth row
}
void loop() {
// TODO
}
Detailed Instructions
Follow these instructions step by step:
- If this is your first time using the Arduino Uno R4 WiFi/Minima, refer to the tutorial on setting up the environment for Arduino Uno R4 WiFi/Minima in the Arduino IDE.
- Connect LCD I2C 20x4 to Arduino UNO R4 according to the provided diagram.
- Connect the Arduino Uno R4 board to your computer using a USB cable.
- Launch the Arduino IDE on your computer.
- Select the appropriate Arduino Uno R4 board (e.g., Arduino Uno R4 WiFi) and COM port.
- Go to the Libraries icon on the left side of the Arduino IDE.
- Type "LiquidCrystal I2C" and look for the LiquidCrystal_I2C library by Frank de Brabander.
- Press the Install button to add the LiquidCrystal_I2C library.
- Copy the code above and open it in Arduino IDE.
- Press the Upload button in Arduino IDE to send the code to Arduino UNO R4.
- Check the result on the LCD.
- Try changing the text and its placement.