Using serial communication without pc

Thanks DAB,

This info is really helpful for me.

What I do the power given by 9v battery....and its work.

Thank you very much.

Hi,

Sorry, I'm quite new to the arduino( and electronic) platform, so apologies in advance if my queries seem silly.

But does that mean i would need to replace the serial.print commands with serial.write or since I would no longer require the laptop interface, can I just get rid of all the serial.print commands in my code?

I am working on getting rid of my laptop interface and just uploading the code onto my arduino board. unfortunately, even after getting rid of all the serial.print commands while retaining all the other essential parts of the code, I dont seem to have it working without the usb to pc connection.

May I know what I'm doing wrong? Am I expected to ADD certain code now ( like the serial.write command) into my code now?

Many thanks for any help with regard to me query!

Hi elizabethmath

I think we need to know a little bit more about what you are trying to do with your Arduino program.

A block diagram and/or your code would be very helpful.

Neil

Please provide the sketch your using,

There is no reason you need the PC connected to run you sketch but there may be something in you code that will help us to help you

I feel so pedantic saying this, but:

      if(temp1!=0)

might be able to be re-written as:

      if(temp1)

and I am having a little trouble grasping the control flow here:

      if(temp1!=0)

      {

        if(temp==0){

        digitalWrite(temp1,LOW);         

        }

is this unreachable code?

You are correct, it would be unreachable but the compiler may not pick up on it

I've been coding lately after a long hiatus, but on bigger machines.  Do micro-controller compilers implement the 'volitile' keyword?  I do not see it very often in code samples on element14.

a lot of them do support it but not too many members fall into the "Advanced" camp where it would make more difference and have more meaning. Perhaps you could provide a blog as to why people should and could use the "Volatile" keyword for declarations of methods and variables.

In this circumstance, 'volitile' prefix tells the compiler that the variable may change spontaneously outside of the current code.  This could be because another thread of execution can change it, or it is reading a hardware input line.  Now, the compiler won't generate spurious 'unreachable code' warnings in this context.  It is also a good reminder to the reader about the special nature of these variables. 

Doing a moments digging on the interweb tells me that 'volatile' also retards automatic p-code optimization.  If I were to type something like:

int N =0;

while (N != Magic_Number_1){}

when N is asynchronously and independently loaded by another thread or the I/O subsystem, the optomiser might be fooled into interpreting this as:

while(1){}

so,

volatile int N =0;

prevents this.