Recently I have linked up a typical 16*2 LCD (Liquid Crystal Display) display to my Arduino Uno and have linked all the pins up.

Here is my connection:(LCD pin first)

1=GND, 2=+5v, 4=11, 6=12, 11=5, 12=4, 12=3, 14=2, 15=backlight positive, 16=backlight negative

#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:

This is the code that is the default for the LCD, I didn't write it.

So I have done all this and when I turn it on the screen is blank and nothing is happening. Could anyone explain what I have done wrong?

  • 1
    What is connected to LCD pin 3? It is the contrast V0 and need to be connected with a 10 Kohm potentiometer. arduino.cc/en/Tutorial/HelloWorld Commented Jan 2, 2016 at 13:08
  • I found connecting the LCD v0 (pin 3) to a 1k resistor to ground worked and provides a fairly viewable contrast. Commented Aug 29, 2020 at 18:21

3 Answers 3


Check out this tutorial on Adafruit. It will walk you through setting it up. In the tutorial they change the pins, which I believe is the issue here. Here is a snippet.

Fritzing Diagram

And change your pins:

LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

Recently I also faced similar problem, with connection as:

1=GND, 2=+5v, 4=11, 6=12, 11=5, 12=4, 12=3, 14=2, 15=backlight positive, 16=backlight negative

Solution: I just connected VEE (pin 3) of LCD to Ground (GND) without use of potentiometer as it worked.

  • 1
    This will get you by in a pinch but at some viewing angles the LCD is hard to read.
    – Ian Pitts
    Commented May 5, 2016 at 13:02
  • If you don't need to constantly adjust the LED backlight brightness you can use a fixed resistor in place of the potentiometer.
    – linhartr22
    Commented Aug 18, 2016 at 19:12
  • This solution also worked for me. Just connect the ground with VEE(pin3) and showing display
    – habib
    Commented Jan 17, 2019 at 18:19
  • worked for me as well
    – Alucard
    Commented Aug 21, 2020 at 1:27

What is connected to LCD pin 3? Pin 3 is the contrast V0 and needs to be connected with a 10 KOhm potentiometer.

Some LCD's need a negative contrast voltage, check the datasheet of the display.

If the contrast voltage is not correct the display will stay blank. I came across the same problem until i saw the negative voltage must be applied :-)

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