I'm having issues with my 20x4 LCD screen

[Cavim154]

I'm not experienced, so I dont know any of the fancy terms that I should know. I'm just a high school student trying to get a good grade on my project. And I've been struggling with my 20x4 lcd display. Most of it works, but there are two lines that run across the entire length of the screen where there are no pixels. I cant figure out the problem. Does anyone understand what I'm saying, and if so can anyone help me?

[UKHeliBob]

Welcome to the forum

Please post the full sketch that you are having problems with

[Cavim154]

Like I said, I don't know any of the terms. Do you mean the code?

[ktauchathuranga]

he means that you have to post the code that u uploaded to your development board,

when you post code/program here use the code block to paste your code here

[groundFungus]

A photo of what you are writing about could be a huge help.

Does it make any difference if you press on the upper and lower edges of the display?

[StefanL38]

Hi @Cavim154

welcome to the arduino-forum.

Best thing is if you post a picture of the LCD showing the display in action
For posting pictures you have to
Get to trust level 1 by…

• Entering at least 5 topics
• Reading at least 30 posts
• Spend a total of 10 minutes reading posts

@Cavim154

I'm just a high school student trying to get a good grade on my project.

well a good grade in your project requires guess what? some learning and some effort.

@Cavim154

but there are two lines that run across the entire length of the screen where there are no pixels.

This means all characters are still readable?
Do you think you get extra-points for polishing the display? I guess not. The most important thing is functionality.

Post your complete code like described here

Make experienced users help: two ways to quickly post code as a code-section

Hi newcomer, This thread wants to show you how you can speed-up getting helpful answers with small effort. If you manage at least to post this way. You have the sympathy of the experienced users. If you are willing to invest another 20 minutes these 20 minutes extra-time will save you a minimum of 200 minutes to finish your project. always post your full sketch. As a code-section from the very first to the very last line A code-section has a small height => keeps your posting "short" but…

[xfpd]

@Cavim154

Most of it works

Describe this.

[gilshultz]

There is a trim pot (the thing with a small screwdriver slot), try adjusting that. It is called the contrast control.

[david_2018]

@Cavim154

Most of it works, but there are two lines that run across the entire length of the screen where there are no pixels. I cant figure out the problem.

Do all the characters display properly? It is normal for each row to be separated by a pixel-height spacing that has no pixels (if you look closely, there is also a pixel-width horizontal spacing between each character).

[Ron_Blain]

I could give you some possible code examples for a LCD but less knowing exactly what you have and your objective it would be a waste. Less seeing your code I doubt anyone here can be of much help. It's a combination of your code and your exact hardware configuration.

Ron

[JohnLincoln]

Are you using the LiquidCrystal library?

If so have you used lcd.begin(20,4) to initialise the LCD correctly?

https://www.arduino.cc/reference/en/libraries/liquidcrystal/begin/

You need to tell the code what size LCD you have - maybe it thinks you only have 2 rows.