Arduino + Sainsmart LCD2004 Serial 16×4 LCD Screen

The Sainsmart LCD2004 is a great big 16 character by 4 line LCD screen that gives you a lot of output space but only using 2 output pins from the arduino instead of 6 output pins.

The unit can be connected via the analog  pin 4 to its SDA (data) and analog pin 5 to its SCL (clock). Each serial device gets a hardware address ranging from 0-127 (7-bit) and the recent batch of these are at I2C 0x3F address but you can change that.

Code

You will need to download the LiquidCrystal_I2C library from here.

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define I2C_ADDR 0x3F // Define I2C Address where the PCF8574A is
#define BACKLIGHT_PIN 3
#define En_pin 2
#define Rw_pin 1
#define Rs_pin 0
#define D4_pin 4
#define D5_pin 5
#define D6_pin 6
#define D7_pin 7

LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin,BACKLIGHT_PIN,POSITIVE);

int n = 1;

void setup() {
  lcd.begin(20,4); // 20 columns by 4 rows on display
  lcd.setCursor(0,0); // go to the top left corner
  lcd.print("Test Message");&nbsp;
}

void loop() {
  lcd.setCursor (16,3); // go to col 16 of the last row
  lcd.print(n++,DEC);&nbsp;
  delay(500); // wait half a second before another update
}