LCD Problems

I have an LCD screen and I wired it up to my Arduino and loaded the "Hello World" sketch to my Arduino and this is gibberish appeared on the screen. The picture is on my blog: What is the problem and how do I fix it? Thanks so much!

Which LCD screen? How exactly is it wired to your Arduino? What exact code are you running?

Bit of a guess based on the hello world 16x2 LCD sample I've seen. The text is in the correct location (including the counter on the 2nd line) so you're not far off. The exclamation point and space characters are displaying correctly (char 32 + char 33), and being lower ASCII values they wont have the more significant bits in use. 'H' (what should be the first char) is character 65 so uses the 2nd most significant bit, as will all the others (excluding the previously mentioned space and !), so I am guessing that the 2nd wire has a bad connection or something along those lines.

I hope that helps.

To elaborate on the previous two posts:

In order to evaluate this properly we have to know exactly what data was sent to the display. Did you send 'Hello World', 'hello world', 'Hello, world!', or some other variation?

We also have to know exactly what characters were displayed. I can't read your display well enough to examine the pixels in the non alphabetic symbols.

We also have to be able to unambiguously follow each wire from one end to the other and also examine the solder connections.


I wrote "hello, world!"

I wrote "hello, world!"

Now if I only knew what was actually displayed for each of those characters I might be able to help. It would also help to know the character set for your particular LCD display which is frequently shown in the datasheet.


OK - I think I have figured it out. You owe me a new pair of glasses.

I believe you have a short, most likely a solder bridge at the LCD pins, between D6 and D7 (LCD pins 13 and 14).


Yes!! You are right! There was a soldering problem with DB7 and DB6. Thank you so much! And I certainly owe you a new pair of glasses! How did you figure that out? :) :) :)

How did you figure that out?

Sorry, that's an ancient Chinese secret.


Haha! I live in Beijing, China!