In this tutorial, you’ll learn how to use a 16×2 LCD display with an I2C interface using the Adafruit_LiquidCrystal library. The code example shows how to display a counter that increments every second and blinks the backlight to create a visual effect.
Below you will find the complete code to use the humidity sensor:
Upload this sketch to display a message:
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2); // Set I2C address 0x27, 16 columns and 2 rows
void setup() {
lcd.init(); // Initialize the LCD
lcd.backlight(); // Turn on the backlight
lcd.setCursor(0, 0); // First column, first row
lcd.print("Hello, World!"); // Print message on first row
lcd.setCursor(0, 1); // First column, second row
lcd.print("I2C LCD Demo"); // Print message on second row
}
void loop() {
// Nothing needed here
}
Let’s review the code section by section:
#include <Adafruit_LiquidCrystal.h>
Includes the Adafruit_LiquidCrystal library that allows you to control the I2C LCD easily.
Make sure to install this library via the Arduino Library Manager.
int seconds = 0;
seconds to store the number of seconds that have passed.
Adafruit_LiquidCrystal lcd_1(0);
Creates an LCD object named lcd_1.
The argument 0 is a reference ID (not the I2C address). In some versions, you might use lcd_1(0x27) or lcd_1(0x3F) depending on your I2C backpack.
void setup() {
lcd_1.begin(16, 2); // Initialize 16x2 LCD
lcd_1.print("hello world"); // Print on first row
}
lcd_1.begin(16, 2); initializes the LCD with 16 columns and 2 rows.
lcd_1.print("hello world"); prints the message starting from the top-left corner (default cursor position).
lcd_1.setCursor(0, 1);
lcd_1.print(seconds);
These lines toggle the backlight on and off every second to create a blinking effect.
seconds += 1;
Increments the counter by 1 each time the loop runs (once per second).
Nothing appears on the LCD:
Text is garbled:
