I2C 4x20 LCD, test on Arduino Uno using LiquidCrystal_I2C library

Test I2C 4x20 LCD on Arduino Uno using LiquidCrystal_I2C library. marcoschwartz/LiquidCrystal_I2C is a LiquidCrystal Arduino library for the DFRobot I2C LCD displays.

- Install LiquidCrystal_I2C library in Arduino Software:

- Open the example of LiquidCrystal_I2C > HelloWorld

//YWROBOT
//Compatible with the Arduino IDE 1.0
//Library version:1.1
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,20,4);  // set the LCD address to 0x27 for a 16 chars and 2 line display

void setup()
{
  lcd.init();                      // initialize the lcd 
  lcd.init();
  // Print a message to the LCD.
  lcd.backlight();
  lcd.setCursor(3,0);
  lcd.print("Hello, world!");
  lcd.setCursor(2,1);
  lcd.print("Ywrobot Arduino!");
   lcd.setCursor(0,2);
  lcd.print("Arduino LCM IIC 2004");
   lcd.setCursor(2,3);
  lcd.print("Power By Ec-yuan!");
}


void loop()
{
}

Test with Arduino Uno:
Uno A4 (SDA) - SDA
Uno A5 (SCL) - SCL
Uno +5V - VCC
Uno GND - GND

Remark:
- It's a jumper on the daughter board on the back side, it have to be insert (short) to turn on the back light.
- Most probably you have to adjust the potentiometer on the daughter board to make the LCD characters clear.
- The I2C address of the board is 0x27, you can check it with i2cdetect library.