LCD with I2C

Problem: How to get information out of the Arduino when it's not plugged into the computer?

Installing the Library

The first thing we need is to install the library to allow us to control an LCD over I2C. If you have never installed a library, you can watch this video that shows you how. This time the library we're looking for is the LiquidCrystal_I2C library which looks like this in the Library Manager:

Just search for "LiquidCrystal_I2C" and scroll down until you see the one from Marco Schwartz and click the Install button.

Wiring the LCD (Leonardo)

Wiring the LCD (Nano)

Example Code

#include <LiquidCrystal_I2C.h> // LCD Library

LiquidCrystal_I2C lcd(0x27, 16, 2); // LCD Declaration, tell the arduino we're using an LCD at I2C address 0x27, 16 column and 2 rows

void setup()

{

  lcd.init(); // initialize the lcd

  lcd.backlight();

}

void loop()

{

  lcd.clear();                // clear LCD display

  lcd.setCursor(0, 0);         // move cursor to   (0, 0)

  lcd.print("Renton Schools");        // write message "Renton Schools" at (0, 0) - This is the upper left corner

  lcd.setCursor(2, 1);         // move cursor to   (2, 1) - This is two squares right and one square down from the upper left corner

  lcd.print("CTE @RentonCTE"); // print message at (2, 1)

  delay(3000);                // display the above for three seconds

  lcd.clear();                  // clear display

  lcd.setCursor(2, 0);         // move cursor to   (2, 0)

  lcd.print("Renton Schools");         // print message at (2, 0)

  lcd.setCursor(0, 1);          // move cursor to   (0, 1)

  lcd.print("CTE @RentonCTE");  // print message at (0, 1)

  delay(3000);                 // display the above for three seconds

}

Note:

There is a potentiometer on the back of the LCD that controls the brightness of the display. This is a small blue box with a grey dial inside. If you install the library, upload the code, and don't see anything on the display, carefully adjust the potentiometer with a screwdriver before trying other solutions. While watching the display, slowly turn the dial all the way one direction, then the other until the words appear.