New to arduino

Hi friend,

I am new to arduino and i am try to understand the function of digital pin in arduino uno boards. I am triggering pin2 as high and reading all the other digital points value but i am getting pin10,pin12and pin13 are reading high.Can any one please let me know how this is happening.

We have no idea how to solve your problem because we can't see it. Please post your code using code tags. The code tags make the code look

like this

when posting source code files. It makes it easier to read, and can be copied with a single mouse click. Also, if you don't do it, some of the character sequences in the code can be misinterpreted by the forum code as italics or funny emoticons.

Unless the sketch is too large, it's better if you post your code, rather than attach it. When it's attached, we have to download it, create a folder then open your code in our IDE. Or perhaps open it in WordPad, which isn't very good for looking at code. And afterwards, the folder remains unless we navigate to the "Temp" folder and manually remove it. It's much easier to just view the code in your post.

Many questions can be answered by reading the documentation which is provided with the IDE, available under the help tab, or online here.

There are many other things that programmers do to make their code understandable. Please do them, as a courtesy to the members who volunteer their time to help you here. One is to use a standard indentation to clearly show the code blocks. Never put more than one statement per line. Place any brackets by themselves on a separate line. Before posting the code, use Ctrl-T in the IDE to reformat the code in a standard format, which makes it easier for us to read. Another is to give things descriptive names. You can name numerical constants, pin numbers, variables and many other things in this way.

Hi “friend” - I don’t really know you, but yeah! Good foot forward!

Everything aarg says is important.

In reference to your question, pins that are not explicitly set to “HIGH” or “LOW” are free to take on whichever state they want, when they want to! In other words, they are floating. When you read them they could be in either state.

The upshot is, set them explicitly in your setup routine, even if you don’t expect to use them in your sketch.