20×4 Character LCD Display (2004A) – Blue Backlight

20×4 Character LCD Display (2004A) – Blue Backlight

This 20×4 character LCD module shows 4 lines of 20 characters in clear white text on a blue backlight. Built around the popular HD44780-compatible controller, it is one of the most widely supported displays in the maker world — perfect for showing sensor readings, menus, status messages and more. Drive it directly over the parallel interface, or add an I2C backpack to control it with just two data pins.

Features

• 20 characters x 4 lines display
• Blue backlight with white characters
• HD44780-compatible controller — huge library support
• Standard 16-pin parallel interface (4-bit or 8-bit mode)
• Adjustable contrast (onboard potentiometer connection)
• I2C-backpack compatible for 2-wire control
• Works with Arduino, ESP32, ESP8266 and Raspberry Pi

Specifications

• Display: 20 x 4 characters (2004A)
• Backlight: Blue
• Character colour: White
• Controller: HD44780-compatible
• Interface: 16-pin parallel (I2C via optional backpack)
• Operating voltage: 5V

Applications

• Displaying sensor data and readings
• Menus, status and information screens
• Arduino / ESP32 / Raspberry Pi projects
• DIY instruments, meters and gadgets

Package Includes

• 1 x 20×4 Character LCD Display (2004A, Blue)

Frequently Asked Questions

How many pins does it use?
A 16-pin parallel interface — or add an I2C backpack to control it with just two data pins.

Which library should I use?
Any HD44780-compatible library, such as LiquidCrystal or LiquidCrystal_I2C.

Is the contrast adjustable?
Yes — contrast is set with a potentiometer, and the blue backlight is on by default.

Recommended Pairings

Works great with our Arduino Nano and ESP32-S3 board. Learn more about the HD44780 controller.