SainSmart 20 x 4 LCD wanting to use I2C from Arduino Uno

Using Arduino Displays
23

Hey buddy,

Try the code below. I was having the exact same problem, but its working nicely with this example.

As mentioned below by Don, static display should go in setup(), and variables should go in loop().

This info is also helping me with my own project :slight_smile: Appreciate the feedback. Will be going from Arduino n00b to competent coder in no time.

Let me know if you have any questions.

Cheers,

Andrew.

/*
** Example Arduino sketch for SainSmart I2C LCD2004 adapter for HD44780 LCD screens
** Readily found on eBay or http://www.sainsmart.com/ 
** The LCD2004 module appears to be identical to one marketed by YwRobot
**
** Edward Comer
** LICENSE: GNU General Public License, version 3 (GPL-3.0)
**
** sain_lcd_2.ino
** Simplified and modified by Andrew Scott for Arudino 1.0.1, Arudino Uno R3.
** NOTE: I2C pins are A4 SDA, A5 SCL
** Don't forget to use the new LiquidCrystal Library.
*/



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

#define I2C_ADDR    0x3F  // Define I2C Address where the SainSmart LCD 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);

void setup()
{
  lcd.begin (20,4);
  
  // Switch on the backlight
  lcd.setBacklightPin(BACKLIGHT_PIN,POSITIVE);
  lcd.setBacklight(HIGH);

  // Position cursor and write some text
  lcd.home ();                   // go to the first line, first character
  lcd.print("SainSmart I2C tester");  
  lcd.setCursor ( 0, 1 );        // go to the 2nd line
  lcd.print("It's Working!");
  lcd.setCursor ( 0, 2 );        // go to the third line
  lcd.print("Sainsmarts docs suck");
  lcd.setCursor ( 0, 3 );        // go to the fourth line
  lcd.print("Nice LCD Though. ");
}

void loop()
{

}

Moderator edit: colour tag swapped for code tags