LCD wont print a word

i tried some projects on youtube about temperature sensor but my lcd wont show any thing even with the hello world example it only shows 1 row of squares on the top row only

i used potentiometer
i connected rw to ground

any help ???

It is hard to help since we have no clue what LCD that you are using or how it is interfaced to the mystery Arduino or the code that you are using.

Read the how to use this forum-please read sticky to see how to properly post code and some advice on how to ask an effective question. Remove useless white space and format the code with the IDE autoformat tool (crtl-t or Tools, Auto Format) before posting code.

Photos of the display and how it is wired is often very helpful.

[code
]#include <LiquidCrystal.h>

// initialize the library by associating any needed LCD interface pin
// with the arduino pin number it is connected to
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

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);
}

[/code]

Code works fine. Confirmed with my Uno and 16x2 LCD with hd44780 controller.

Nearly every LCD tutorial on the net has a potentiometer wired from Vcc and ground with the wiper to pin 3 of the LCD. That is not really right (though the LCD will work that way). Remove the wire from Vcc to one end of the pot so that it is a variable resistor from pin 3 of the LCD to ground and set the pot to get the best contrast.

A photo of your wiring, please. What Arduino?

Did you read the how to use this forum-please read sticky in respect to what we need to know in order to help you (see #11)?

oh sorry it took me while to edit the post u can see my wiring

oh btw i already removed the vcc from the one end of the pot which isnt showed it the picture


Sorry, I did not see that you had attached the image. Here us how to post images so we don't have to download them.

Many breadboards have the power rails split in the center. If yours is one of those, the RW pin is not grounded but open, I think.


Tie the rails together in the middle like shown in this image.

Sorry again, it is probably not the breadboard because I just noticed that the backlight works.

I can't really see where the wires go on the Uno. Nor a clear view of the solder joints on the LCD header.

Adjust the contrast to where you can see the blocks again. Instead of a pot, I usually use just a 1K resistor from pin 3 of the LCD to ground. That give good contrast on every LCD that I have used.

We know that the code works so it almost has to be a hardware problem. We just have to find it.

groundFungus:
. . .

Many breadboards have the power rails split in the center. If yours is one of those, . . .


Tie the rails together in the middle like shown in this image.

Hint: The breadboards that have the power rails split in the center also have the blue and red lines split in the center.

His is not one of those as evidenced by his photograph.

Don