fmalpartida NewLiquidCrystal Libararies and 1602 I2C

I'm trying to use these newer libraries for my 1602 IIC LCD screen.Here.

I'm trying the Hello World example for I2C To see if it works but I have issues with the back light. Without altering the code with #define BACKLIGHT_PIN 13 the backlight flickers on and off. Do I use the pin that is connected to the Nano or do I reference some other pin?

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



#define BACKLIGHT_PIN     13

LiquidCrystal_I2C lcd(0x27);  // Set the LCD I2C address

//LiquidCrystal_I2C lcd(0x38, BACKLIGHT_PIN, POSITIVE);  // Set the LCD I2C address


// Creat a set of new characters
const uint8_t charBitmap[][8] = {
   { 0xc, 0x12, 0x12, 0xc, 0, 0, 0, 0 },
   { 0x6, 0x9, 0x9, 0x6, 0, 0, 0, 0 },
   { 0x0, 0x6, 0x9, 0x9, 0x6, 0, 0, 0x0 },
   { 0x0, 0xc, 0x12, 0x12, 0xc, 0, 0, 0x0 },
   { 0x0, 0x0, 0xc, 0x12, 0x12, 0xc, 0, 0x0 },
   { 0x0, 0x0, 0x6, 0x9, 0x9, 0x6, 0, 0x0 },
   { 0x0, 0x0, 0x0, 0x6, 0x9, 0x9, 0x6, 0x0 },
   { 0x0, 0x0, 0x0, 0xc, 0x12, 0x12, 0xc, 0x0 }
   
};

void setup()
{
   int charBitmapSize = (sizeof(charBitmap ) / sizeof (charBitmap[0]));

  // Switch on the backlight
  pinMode ( BACKLIGHT_PIN, OUTPUT );
  digitalWrite ( BACKLIGHT_PIN, HIGH );
  
  lcd.begin(16,2);               // initialize the lcd 

   for ( int i = 0; i < charBitmapSize; i++ )
   {
      lcd.createChar ( i, (uint8_t *)charBitmap[i] );
   }

  lcd.home ();                   // go home
  lcd.print("Hello, ARDUINO ");  
  lcd.setCursor ( 0, 1 );        // go to the next line
  lcd.print (" FORUM - fm   ");
  delay ( 1000 );
}

void loop()
{
   lcd.home ();
   // Do a little animation by writing to the same location
   for ( int i = 0; i < 2; i++ )
   {
      for ( int j = 0; j < 16; j++ )
      {
         lcd.print (char(random(7)));
      }
      lcd.setCursor ( 0, 1 );
   }
   delay (200);
}

Your link points to the currently recommended library but you have to make sure that it was installed properly and that you are using the correct constructor.

You really should look at the wiki where Francisco explains a lot about the library. Here

Make sure you scroll all the way down and follow the instructions pertaining to getting rid of your existing library or libraries.

After you have installed the library correctly you will need to run the I2C guesser sketch. You can find a link to it in this forum post. I hope this points to the latest version - look for Bill (the author) to join in with an update.

Finally - no matter how you have interfaced your LCD and no matter which library you are using you should use the simplest sketch possible to test your setup. This means you don't want to mess with special characters and you don't want to put any code in loop. Look at Francisco's examples.

Don