How to Use I2C LCD with ESP32 Using Arduino IDE

This tutorial shows how to use the I2C LCD (Liquid Crystal Display) with the ESP32 using Arduino IDE. We’ll show you how to wire the display, install the library and try sample code to write text on the LCD: static text, and scroll long messages. You can also use this guide with the ESP8266.

16×2 I2C Liquid Crystal Display

For this tutorial we’ll be using a 16×2 I2C LCD display, but LCDs with other sizes should also work. The advantage of using an I2C LCD is that the wiring is really simple. You just need to wire the SDA and SCL pins.

Connect LCD to the ESP32

This display uses I2C communication, which makes wiring really simple. Wire your LCD to the ESP32 by following the next schematic diagram. We’re using the ESP32 default I2C pins (GPIO 21 and GPIO 22).

I2C LCD	ESP32
GND	GND
VCC	VIN
SDA	GPIO 21
SCL	GPIO 22

Wiring the LCD to the ESP8266

You can also wire your LCD to the ESP8266 by following the next schematic diagram. We’re using the ESP8266 default I2C pins (GPIO 4 and GPIO 5).

	ESP8266
GND	GND
VCC	VIN
SDA	D2 (GPIO 4)
SCL	D1 (GPIO 5)

Preparing the Arduino IDE For ESP32

There’s an add-on for the Arduino IDE that allows you to program the ESP32 using the Arduino IDE and its programming language. Follow one of the next guides to prepare your Arduino IDE to work with the ESP32: Installing the ESP32 Board in Arduino IDE | ESP32

Preparing the Arduino IDE For ESP8266

There’s also an add-on for the Arduino IDE that allows you to program the ESP8266 using the Arduino IDE. Read: How to Install the ESP8266 Board in Arduino IDE.

Installing the LiquidCrystal_I2C Library

There are some libraries that work with the I2C LCD. We’re using this library by Marco Schwartz. Follow the next steps to install the library:

1. Click here to download the LiquidCrystal_I2C library. You should have a .zip folder in your Downloads
2. Unzip the .zip folder and you should get LiquidCrystal_I2C-master folder
3. Rename your folder from LiquidCrystal_I2C-master to LiquidCrystal_I2C
4. Move the LiquidCrystal_I2C folder to your Arduino IDE installation libraries folder
5. Finally, re-open your Arduino IDE

Getting the LCD Address

Before displaying text on the LCD, you need to find the LCD I2C address. With the LCD properly wired to the ESP32, upload the following I2C Scanner sketch.

#include <wire.h>
 
void setup() {
  Wire.begin();
  Serial.begin(115200);
  Serial.println("\nI2C Scanner");
}
 
void loop() {
  byte error, address;
  int nDevices;
  Serial.println("Scanning...");
  nDevices = 0;
  for(address = 1; address < 127; address++ ) {
    Wire.beginTransmission(address);
    error = Wire.endTransmission();
    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address<16) {
        Serial.print("0");
      }
      Serial.println(address,HEX);
      nDevices++;
    }
    else if (error==4) {
      Serial.print("Unknow error at address 0x");
      if (address<16) {
        Serial.print("0");
      }
      Serial.println(address,HEX);
    }    
  }
  if (nDevices == 0) {
    Serial.println("No devices found\n");
  }
  else {
    Serial.println("done!\n");
  }
  delay(5000);          
}

After uploading the code, open the Serial Monitor at a baud rate of 115200. Press the ESP32 EN button. The I2C address should be displayed in the Serial Monitor. In my case the address is 0x27. If you’re using a similar 16×2 display, you’ll probably get the same address.

Display Static Text on the LCD

Displaying static text on the LCD is very simple. All you have to do is select where you want the characters to be displayed on the screen, and then send the message to the display. Here’s a very simple sketch example that displays “Hello, World!“.

#include <LiquidCrystal_I2C.h>

// set the LCD number of columns and rows
int lcdColumns = 16;
int lcdRows = 2;

// set LCD address, number of columns and rows
// if you don't know your display address, run an I2C scanner sketch
LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows);  

void setup(){
  // initialize LCD
  lcd.init();
  // turn on LCD backlight                      
  lcd.backlight();
}

void loop(){
  // set cursor to first column, first row
  lcd.setCursor(0, 0);
  // print message
  lcd.print("Hello, World!");
  delay(1000);
  // clears the display to print new message
  lcd.clear();
  // set cursor to first column, second row
  lcd.setCursor(0,1);
  lcd.print("Hello, World!");
  delay(1000);
  lcd.clear(); 
}

It displays the message in the first row, and then in the second row. In this simple sketch we show you the most useful and important functions from the LiquidCrystal_I2C library.

How the code works

First, you need to include the LiquidCrystal_I2C library.

#include <LiquidCrystal_I2C.h>

The next two lines set the number of columns and rows of your LCD display. If you’re using a display with another size, you should modify those variables.

int lcdColumns = 16;
int lcdRows = 2;

Then, you need to set the display address, the number of columns and number of rows. You should use the display address you’ve found in the previous step.

LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows);

In the setup(), first initialize the display with the init() method.

lcd.init();

Then, turn on the LCD backlight, so that you’re able to read the characters on the display.

lcd.backlight();

To display a message on the screen, first you need to set the cursor to where you want your message to be written. In the following line, we set the cursor to the first column, first row.

lcd.setCursor(0, 0);

Note

: 0 corresponds to the first column, 1 to the second column, and so on…

Then, you can finally print your message on the display using the print() method.

lcd.print("Hello, World!");

We wait one second, and then we clean the display with the clear() method.

lcd.clear();

After that, we set the cursor to a new position: first column, second row.

lcd.setCursor(0,1);

And then, the process is repeated.

So, here’s a summary of the functions to manipulate and write on the display:

• lcd.init(): initializes the display
• lcd.backlight(): turns the LCD backlight on
• lcd.setCursor(int column, int row): sets the cursor to the specified column and row
• lcd.print(String message): displays the message on the display
• lcd.clear(): clears the display

This example works well to display static text no longer than 16 characters.

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In summary, in this tutorial we’ve shown you how to use an I2C LCD display with the ESP32/ESP8266 with Arduino IDE. I hope you like this post. Do you have any questions? Leave a comment down below!

Thanks for reading. If you like this post probably you might like my next ones, so please support me by subscribing my blog.

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