20X4 LCD not displaying anything when following the tutorial

I am using this tutorial and the LCD screen isnt showing anything.
The screen lights up but i get no letters.

Do I need to modify the program for the 20x4 LCD. Do i need to supply 5V and ground to other pins?

Thanks

This is the LCD I am using.

Thanks!

/*
  LiquidCrystal Library - Hello World
 
 Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
 library works with all LCD displays that are compatible with the 
 Hitachi HD44780 driver. There are many of them out there, and you
 can usually tell them by the 16-pin interface.
 
 This sketch prints "Hello World!" to the LCD
 and shows the time.
 
  The circuit:
 * LCD RS pin to digital pin 12
 * LCD Enable pin to digital pin 11
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * LCD R/W pin to ground
 * 10K resistor:
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 
 Library originally added 18 Apr 2008
 by David A. Mellis
 library modified 5 Jul 2009
 by Limor Fried (http://www.ladyada.net)
 example added 9 Jul 2009
 by Tom Igoe
 modified 22 Nov 2010
 by Tom Igoe
 
 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/LiquidCrystal
 */

// include the library code:
#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

void setup() {
  // set up the LCD's number of columns and rows: 
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print("hello, world!");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
  lcd.setCursor(0, 1);
  // print the number of seconds since reset:
  lcd.print(millis()/1000);
}

double type

The screen lights up but i get no letters.

What do you see with just the power, contrast, and backlight connected (pins 1, 2, 3, 15, and 16)?

You should see 'blocks' on the first and third rows.

Do I need to modify the program for the 20x4 LCD.

Not for this particular sketch. If you want to use the bottom two lines you will have to modify the lcd.begin(16, 2);

statement which should really be commented: lcd.begin(16, 2);  // put your LCD parameters here.

Do i need to supply 5V and ground to other pins?

That depends on which pins you have already supplied 5V and ground to, which you haven't told us.

Don

floresta: What do you see with just the power, contrast, and backlight connected (pins 1, 2, 3, 15, and 16)?

You should see 'blocks' on the first and third rows.

Not for this particular sketch. If you want to use the bottom two lines you will have to modify the lcd.begin(16, 2);

statement which should really be commented: lcd.begin(16, 2);  // put your LCD parameters here.

That depends on which pins you have already supplied 5V and ground to, which you haven't told us.

Don

I only hooked up these wires LCD RS pin to digital pin 12 * LCD Enable pin to digital pin 11 * LCD D4 pin to digital pin 5 * LCD D5 pin to digital pin 4 * LCD D6 pin to digital pin 3 * LCD D7 pin to digital pin 2 * LCD R/W pin to ground * 10K resistor: * ends to +5V and ground * wiper to LCD VO pin (pin 3)

It appears I need power and ground at 1,2 and 15,16 Thanks

So, are you going to tell us, or just muck about?

floresta:
What do you see with just the power, contrast, and backlight connected (pins 1, 2, 3, 15, and 16)?

Do you know what the contrast control does?

Paul__B: So, are you going to tell us, or just muck about? Do you know what the contrast control does?

I am getting weird results, I have uploaded the pictures here. http://forum.arduino.cc/index.php?topic=311533.0

Thank you