Example Code for Arduino-Hello World and Custom Characters

Wiring Diagram

V1.2 has a different power pinout from V1.1, please check the history version for the old connection diagram.

• Arduino UNO: connect SDA to pin A4 and SCL to pin A5 on your Arduino.
• Arduino Leonardo: connect SDA to digital pin 2 and SCL to digital pin 3 on your Arduino.

Other Preparation Work

If you want to use the library's own sample code, pay attention to modify the initialization statement, need to change:

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

to:

 LiquidCrystal_I2C lcd(0x20,20,4); // set the LCD address to 0x20 for a 20 chars and 4 line display(All jumpers should be connected\!)

Because the default initialization statement is for LCD1602!

Sample Code

//Please download the Arduino library!
//The link:https://www.dfrobot.com/image/data/DFR0154/LiquidCrystal_I2Cv1-1.rar
//DFRobot.com
//Compatible with the Arduino IDE 1.0
//Library version:1.1
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#if defined(ARDUINO) && ARDUINO >= 100
#define printByte(args)  write(args);
#else
#define printByte(args)  print(args,BYTE);
#endif

uint8_t bell[8]  = {0x4,0xe,0xe,0xe,0x1f,0x0,0x4};
uint8_t note[8]  = {0x2,0x3,0x2,0xe,0x1e,0xc,0x0};
uint8_t clock[8] = {0x0,0xe,0x15,0x17,0x11,0xe,0x0};
uint8_t heart[8] = {0x0,0xa,0x1f,0x1f,0xe,0x4,0x0};
uint8_t duck[8]  = {0x0,0xc,0x1d,0xf,0xf,0x6,0x0};
uint8_t check[8] = {0x0,0x1,0x3,0x16,0x1c,0x8,0x0};
uint8_t cross[8] = {0x0,0x1b,0xe,0x4,0xe,0x1b,0x0};
uint8_t retarrow[8] = { 0x1,0x1,0x5,0x9,0x1f,0x8,0x4};

LiquidCrystal_I2C lcd(0x20,20,4);  // set the LCD address to 0x20 for a 20 chars and 4 line display (All jumpers should be connected!)

void setup()
{
//  Serial.begin(57600);
  lcd.init();                      // initialize the lcd
  lcd.backlight();

  lcd.createChar(0, bell);
  lcd.createChar(1, note);
  lcd.createChar(2, clock);
  lcd.createChar(3, heart);
  lcd.createChar(4, duck);
  lcd.createChar(5, check);
  lcd.createChar(6, cross);
  lcd.createChar(7, retarrow);
  lcd.home();

  lcd.setCursor(0, 0);
  for(int i = 0;i < 20; i++)  lcd.printByte(6);
  lcd.setCursor(0, 1);
  lcd.printByte(6);
  lcd.print("   Hello world    ");
  lcd.printByte(6);
  lcd.setCursor(0, 2);
  lcd.printByte(6);
  lcd.print("  i ");
  lcd.printByte(3);
  lcd.print(" arduinos!   ");
  lcd.printByte(6);
  lcd.setCursor(0, 3);
  for(int i = 0;i < 20; i++)  lcd.printByte(6);
//  lcd.clear();

}

void loop()
{

}