LCD screen won't display anything

Hello, I am building a temperature and humidity sensor but the result won't be displayed on the LCD I have attached. I have checked many times and all the wire connections are correct and the LCD does light up but nothing is displayed on it. I used all the connections from this link https://www.arduino.cc/en/Tutorial/LibraryExamples/HelloWorld .Does anyone know what is wrong?

Show us a good schematic of your circuit.
Show us a good image of your ‘actual’ wiring.
Give links to components.


In the Arduino IDE, use Ctrl T or CMD T to format your code then copy the complete sketch.

Use the </> icon from the ‘reply menu’ to attach the copied sketch.

That example contains a longstanding and foolish error.

Remove the connection from the potentiometer to the 5 V. Connect both ends of the potentiometer to ground.

Adjust the potentiometer until you see the expected text, or "blocks" on the first line.

Tell us what you see then.

Thanks for the help, I have tried what you suggested but it still does not work here is a picture for reference:

Double check your wiring. Check if you forgot to add any external connections. Check the code. If it still doesn't work maybe there's some problem with the LCD itself.

Hi @eagle99

Wow, from the picture the potentiometer is wired wrong.
The two ends of it are linked in GND.

One should be connected to GND and the other to +5V.

Have you already varied the intensity setting (the potentiometer) to see if something appears on the LCD?

Test to identify possible LCD problem.

Turn off all LCD connections and leave only GND +5V connected. and the Intensity Adjustment Potentiometer.

Turn on the arduino.

In Line 0, (the top) should appear all full of dark squares and line 1 (bottom) should be clean (blue).

RV mineirim

There is nothing wrong with this. In fact it is a very good idea.

The real problem is your rats nest wiring.
Just connect the 100mm male-male jumper leads from breadboard to Uno GND, 5V, D2-D9. If you place the wires in straight lines it is easy to view on a photo.

Neat wires are easy for you to check. If you document the wire colors foreign eyes can check your wiring.

Just like neatly formatted code, neatly wired breadboards pay dividends.
It might take 10 minutes from your life but it means that you save hours of forum messages.

David.

Thanks a lot for the help, I have tried what you have suggested and changed the wirings but I am still not having anything displayed.

Post a photo of your neat wiring.

Your problems will get solved !

Note that cheap Chinese male-male jumpers often break. But the wiring is always the first thing to check.

David.

Here you go:

You are not using the breadboard properly.

image

image

image

Have you tried adjusting the contrast pot? If the LCD is getting power it should display a row of blocks on the top row, even with the data and control pins disconnected.

The wiring of the contrast pot is not right, yet. Both ends should go to ground and the wiper goes to Vo (LCD pin 3), though it should still work.

Thanks, you said that the top row should be black but in my case the whole LCD screen is blue.

What is written on the potentiometer ?

Let’s see your new potentiometer wire changes ?

Thanks, it says B103

The LCD should look like this with power applied and before it is initialized. If it just blank, adjust the contrast pot to see if you can get the blocks to appear. If they will not, please tell us, and we can try to find out why.

lcd 1602 blocks

Let’s see your new potentiometer wire changes ?

Yeah thanks, the pot is just completely blank.

The wiper is connected to V0 and the others are: one to gnd and the other to 5V

Not that we don’t believe you, please show us a new image as it is now.