How to stop two arduino from communicating?

Projects Networking, Protocols, and Devices
1

Hi everyone, I have the following code for the sender:
(I connected two boards with pins TX, RX)

void setup() {
  // put your setup code here, to run once:
   Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
 Serial.write(13);
}

And for the receiver:

int receive = 0;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
   if(Serial.available())
   {
    receive = Serial.read();
    if(receive == 13)
    {
      Serial.print("I love arduino");
    }
   }
}

When I go to the serial port monitor, I can see the words "I love arduino" appear every second. And that's what I want to achieve, except I don't want subtitles to last forever. What do I do to stop broadcasting after sending a message?

2

If your intent is for it to happen once, when the Arduinos wake up, then put it in setup, not in loop().

3

Put the print message in the setup() portion of code. The loop can be loop(){}. It will print once then stop. I would add this to the code Serial.print("\n\n\tI love..."); That will give you two blank lines at the start and tab the message in to make it easier to read.

4

But clearly, you need a power up sequence so that A starts sending 13, B wakes up, sees that and acknowledges, then A stops sending 13.
At least, that's what I make of your somewhat tenuous description of what needs to happen.
C

5

???

You could set a flag to indicate that the message has already been set:

   {
    static boolean messageHasBeenSent = false;
    receive = Serial.read();
    if(receive == 13 && messageHasBeenSent == false)
    {
      Serial.print("I love arduino");
      messageHasBeenSent = true;
    }
   }

The 'static' means "This variable is initialized once, and (if changed) keeps its (changed) value even after the function ends." Without it, the variable would be re-created and re-initilized every time that line was executed.

6

Thank you, it helped me! :grinning:

7

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