Go Down

Topic: 1602a 16X2 LCD is blank (Read 7 times) previous topic - next topic


I am using 1602a 16x2 LCD with Arduino Uno V3. My board version is 1.0.3

I am using following code:

Code: [Select]
  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.


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

// initialize the library with the numbers of the interface pins
//LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
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:

Here is the datasheet:

I attached everything as suggested and also soldered the lcd.

But the LCD is totally blank. The back light is working fine. I added the delay(200) after reading some threads with similar issue but same problem.

Any help please?


One more thing, when I compile the code/upload it, it shows no error and arduino led suggests the the code is uploaded successfully.



I am just dealing with the same problems, except mine show some squares on the screen. I do not have much knowlegde in this as this is my first time working with it, but have you installed the 10K potentiometer? when i turn my down the contrast is turned down and then the display look like yours.


Jan 31, 2013, 09:47 pm Last Edit: Jan 31, 2013, 09:49 pm by floresta Reason: 1
Your photographs are better than some that I have seen but it is still difficult to follow all the wires.  It looks like your connections are OK, but I can't be sure.

On the other hand your soldering looks like it could use some improvement.  I suggest you try and get all of the LCD connections to look like the one at D5, nice and shiny with no holes.  You already have used too much solder on each joint so don't add any more unless you need more flux, then be sure to remove all of the excess solder.

Here's my quick and dirty LCD setup procedure from a recent post:

1.  Get the backlight working first (pins 15 and 16).
2.  Connect the power and the contrast next (pins 1, 2, and 3).  Any potentiometer between 5K and 50K will work.  With the potentiometer at one end of it's range the display will be blank and at the other end you should see boxes on the top line of the display.  Adjust the potentiometer until the row of boxes is visible, but dim.  The voltage at pin 3 should be around 0.5v at this point.  If you do not get this behavior then it makes no sense to continue since no amount of programming will fix things.
3.  Connect the other seven pins (4, 5, 6, 11, 12, 13, and 14) and load up your sketch.

One more thing, when I compile the code/upload it, it shows no error and arduino led suggests the the code is uploaded successfully.

See the last sentence of #2 above.


Nick Gammon

Yes, the connection to RS in particular (4th from the left) looks like it hasn't taken. The solder should flow into a nice blob. If it isn't soldered properly, pushing the LCD into the board may push the pin up and not touch the contact.

Go Up