This is my ezLCDuino Backpack. It is an Arduino LCD backpack. This will solder on directly onto the back of a LCD allowing you to control it using the Arduino LCD library. I designed the kit along with the PCB.


  • FTDI programming port
  • I2C communication pins
  • Serial communication pins (hardware and software)
  • Trim pot for adjusting the LCD contrast
  • Arduino Atmega 328
  • 4 spare Analog pins (not including the ones used for I2C communication)
  • 3 spare digital pins (not including the ones used for serial communication)
  • PWM control of the backlight
  • Resistors allow the Arduino to be programmed without unplugging devices connected to the TX and RX pins

On the bottom of the board is what I call the "communication row". Here are I2C pins, hardware serial pins, and 2 digital pins you can use for software serial. Down here is also where you power the board. The pins you do not use for communication can be used for a different purpose of your choose. I suggest Bill Porter's serial library for communication.

On the side of the board are the left over pins. This gives a total of 7 digital pins and 6 analog pins on the board excluding the LCD connection at the top.

So use the board as a serial or I2C LCD backpack, use it as the main micro controller in your project that contains a LCD, or use it as a slave to control the LCD in your project and provide extra pins and processing power.

Version 1.2

There are resistors on the UART pins to allow users to program the Arduino without unplugging what they have connected the TX and RX lines. There is an added 10uf cap. A transistor allows the backlight to be turned on and off or PWMed from pin 9.

Version 1.1

Added more power connections on the communication row so the board can be interfaced to using a 4 or 3 pin cable depending on if you are using I2C or using serial with just RX or with TX as well.

Version 1.0

Final Circuit Board

Surface Mount Version

I have also designed a surface mount version of the ezLCDuino. It has all the same capabilities but it is a smaller form factor. You can see pictures of the the EagleCAD design and final assembly below. Soldering this board is harder however