How to Use LCD Display 16x4 I2C: Examples, Pinouts, and Specs

An LCD (Liquid Crystal Display) is a flat panel display technology commonly used in TVs, computer monitors, and small screen devices like digital watches and calculators. The 16x4 I2C LCD Display is a character display with 16 columns and 4 rows, allowing for the display of up to 64 characters at a time. This display uses the I2C communication protocol, which reduces the number of pins required for operation, making it ideal for use with microcontrollers with limited GPIO pins, such as the Arduino UNO.

• User interfaces for electronic devices
• Real-time data output displays
• Debugging information for embedded systems
• Small message boards

• Display Type: Character LCD
• Resolution: 16 characters x 4 lines
• Backlight: LED, typically blue or green
• Character Size: Usually 5x8 or 5x10 dots
• I2C Address: Commonly 0x27 or 0x3F (may vary)
• Supply Voltage: Typically 5V
• Logic Voltage: 5V
• Module Dimensions: Varies by manufacturer

1. Connect the GND pin to the ground of the power supply.
2. Connect the VCC pin to a 5V power supply.
3. Connect the SDA and SCL pins to the I2C data and clock lines on the microcontroller.
4. If available, connect the backlight control pin to a digital output on the microcontroller if you wish to control the backlight.

• Ensure that pull-up resistors are connected to the SDA and SCL lines if they are not already present on the LCD module.
• Use a level shifter if you are interfacing with a microcontroller operating at a logic level other than 5V.
• Avoid exposing the display to direct sunlight or high temperatures to prevent damage.
• Handle the display with care to avoid static discharge or physical damage to the screen.

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Initialize the library with the I2C address found for your display
LiquidCrystal_I2C lcd(0x27, 16, 4);

void setup() {
  // Initialize the LCD and specify the dimensions
  lcd.init();
  lcd.backlight();

  // Print a message to the LCD
  lcd.setCursor(0, 0); // Set the cursor to column 0, row 0
  lcd.print("Hello, World!");
  lcd.setCursor(0, 1); // Move to the second row
  lcd.print("LCD 16x4 I2C");
}

void loop() {
  // Main loop - nothing to do here
}

• Display not powering on: Check the wiring, especially the VCC and GND connections.
• Characters not displaying correctly: Verify the I2C address and ensure proper initialization in the code.
• Garbled text or random characters: Reset the power to the LCD and check for loose connections.

• Use an I2C scanner sketch to confirm the I2C address of the LCD.
• Ensure that the contrast is properly adjusted if your display has a contrast potentiometer.
• Check for soldering issues on the I2C interface module if it's a separate component.

Q: How do I find the I2C address of my LCD? A: Use an I2C scanner sketch to scan and find the address of your device.

Q: Can I use this display with a 3.3V system? A: Yes, but you may need a level shifter for proper operation and to protect the 3.3V system.

Q: Is it possible to control the backlight? A: Yes, if your module has a backlight control pin (NC), you can connect it to a PWM-capable pin on your microcontroller for backlight control.

Q: How can I display custom characters? A: The LiquidCrystal_I2C library allows you to create custom characters. Refer to the library documentation for instructions on how to define and display them.