If Serial Available Function

Projects Programming
1

Hi,

I am quite new to Arduino. Anyway, I am trying to program a robot arm to do a certain action. I want the action I programmed to start when I enter something in the serial port. When I tried to use the "if (Serial.available() > 0)," the action would constantly loop over and over. I want to press the key once and have the action play out once, and then press it again when I want the action to play out again. Sorry, I do not have the code with me now, but here is how my code roughly looks:

void loop() {

//The starting position is programmed here. Whenever the action finishes, it loops back to the
//this position.

if (Serial.available() > 0) {
//The action I want to use is programmed here
}
}

Thank you for the help.

2

Probably best to show us your sketch when you can so we can see what you are doing.
.

4 
char buf[256];
int number_of_chars_in_buf = 0; // buffer starts empty

void loop() {
  if(!Serial.available()) return;

  // we have a character on the serial!

  buf[number_of_chars_in_buf++] == Serial.read();
  buf[number_of_chars_in_buf] = '\0'; // nul terminate the string

  work out if the buffer now contains a command I recognize.
  usually, we just see if the final character is some sort of command terminator, like '\n'

  if(it doesn't) {
    return;
  }

  parse the command, splitting it up into its parts;
  string manipulation, use atoi(), put parts of the command into
  different variables;

  do the thing - whatever it may be.
  this will probably be a big switch() statement;

  number_of_chars_in_buf = 0; // set the buffer back to empty.  
}

You can call it 'command' instead of 'buf'. If you are using newlines to delimit commands, then 'ln' or 'inputLine' might be appropriate.

5

Have a look at the 2nd and 3rd examples in Serial Input Basics.

Also look at how to organize your code into functions in Planning and Implementing a Program. That will make it much easier to manage and extend your program.

Your code in loop() could be something like this

void loop() {
   recvWithStartEndMarkers();
   updateArmPosition();
   moveArmToPosition();
}

...R