Basics of LCD Display
LCD stands for Liquid Crystal Display. It uses liquid crystals to produce visible output. When an electrical voltage is applied, the liquid crystals align in a specific way, allowing light from the backlight to pass through and form characters or images on the screen.
Why Use an LCD in an Arduino Project?
In embedded systems, processes often need continuous monitoring until completion. In such cases, an LCD becomes very useful. Adding an LCD makes the project more interactive and provides real-time feedback to the user.
A common example is a coffee vending machine, where an LCD displays information such as the available coffee quantity or selected options. This allows users to easily understand system status and make selections.
Although many display options are available—such as seven-segment displays, TFT LCDs, and OLED screens—the 16×2 LCD remains the most cost-effective choice for simple text-based applications.
Pinout Details of 16×2 LCD Display
VCC and GND
These pins supply power to the LCD from the Arduino.
VEE
This pin is used to adjust the contrast of the display.
LED+ and LED−
These pins power the LCD backlight and are connected to the Arduino’s VCC and GND.
RS (Register Select)
The LCD contains two registers: a command register and a data register.
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RS = HIGH → data sent is treated as display data
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RS = LOW → data sent is treated as a command
R/W (Read/Write)
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LOW → write mode
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HIGH → read mode
DB0–DB7
These pins transfer data or commands to the LCD.
EN (Enable)
This pin activates the LCD to accept commands or data.
Interfacing LCD with Arduino
Required Components
Hardware Parts
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Arduino Board
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16×2 LCD Display
Software Parts
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Arduino IDE
The LCD is powered directly from the Arduino. The VEE pin is connected to a potentiometer to control display contrast. If a potentiometer is unavailable, the VEE pin can be connected directly to the Arduino’s 3.3V pin.
The LED+ and LED− pins are connected to VCC and GND. Data pins DB4, DB5, DB6, and DB7 are connected to Arduino digital pins 5, 4, 3, and 2 respectively. The RS and EN pins are connected to digital pins 11 and 12, while the R/W pin is grounded to enable write mode.
LCD Arduino Code:
#include <LiquidCrystal.h>
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); // sets the interfacing pins
void setup()
{
lcd.begin(16, 2); // initializes the 16x2 LCD
lcd.setCursor(0, 0); // sets the cursor at row 0, column 0
lcd.print("LCD Tutorial"); // displays text
lcd.setCursor(5, 1); // sets the cursor at row 1, column 5
lcd.print("HELLO WORLD"); // displays text
}
void loop()
{
// Your code here
}