Bigger display, fewer wires! This 20×4 I2C LCD (2004A) shows 20 characters across 4 rows — 80 characters total — with a bright blue backlight, and thanks to the pre-soldered I2C module it needs only 2 data wires (SDA, SCL) instead of the usual 10+. Ideal when your Arduino project needs to show sensor readings, menus, or status messages at a glance. Pairs perfectly with any Arduino board.

Key Features

• 20×4 character display (20 columns x 4 rows = 80 characters)
• I2C interface — only 2 data wires needed (SDA, SCL)
• Bright blue backlight, clear and easy to read
• I2C module pre-soldered with contrast adjustment potentiometer
• Low power consumption
• Easy to use with Arduino via the LiquidCrystal_I2C library
• Mounting holes for clean panel installation
• High quality and durable

How to Connect (Usage)

Wire the module to your Arduino UNO as follows:

Arduino Example Code

Needs the LiquidCrystal_I2C library — install it from Arduino IDE Library Manager:

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

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("QKZee Technologies");
  lcd.setCursor(0, 1);
  lcd.print("20x4 LCD Ready!");
}

void loop() {
}

Note: most modules use I2C address 0x27; if nothing appears, try 0x3F. See more display options in our LCD & Displays collection — find it under the Shop categories.

Applications

• Sensor monitoring dashboards (temperature, humidity, air quality)
• Home automation control panels
• Arduino projects needing text output
• Robotics Projects — see our Robotics parts
• Industrial control systems and timers
• DIY electronics and student projects — pair it with Sensors

Frequently Asked Questions

Q: How many wires do I need to connect it?

A: Just four in total: VCC, GND, SDA and SCL — only two carry data, which is the whole point of the I2C version.

Q: What is the difference between 20×4 and 16×2?

A: The 20×4 shows 80 characters (20 columns x 4 rows) versus 32 on a 16×2 — more than double the information on screen, great for menus and multi-sensor readings.

Q: What is the I2C address?

A: Usually 0x27 (a few modules use 0x3F). Set it in the LiquidCrystal_I2C lcd(…) line; if the screen stays blank, try the other address and adjust the contrast potentiometer on the I2C module.

Q: Does it work with ESP32 or Raspberry Pi?

A: Yes — it works with Arduino, ESP32 and Raspberry Pi (via I2C). Power it from 5V.

Q: Can I adjust the brightness/contrast?

A: The blue backlight is fixed, but the small blue potentiometer on the I2C module adjusts character contrast — turn it gently with a screwdriver until the text is crisp.

Q: Where can I buy a 20×4 LCD in Pakistan?

A: Right here — QKZee Technologies stocks it at our Hall Road, Lahore shop with Cash on Delivery across Pakistan.