Trouble with null characters in Arduino

Question

I am trying to write an Arduino program that will translate a text string transmitted through the Serial Monitor to Morse code. This is the offending function:

void serialEvent() {
  while (Serial.available()){
    char inChar = Serial.read();
    input += inChar;
    if (inChar == '\0'){  
      Serial.print("END!");
      stringComplete = true;
    }
  }
}

It should take characters from the serial input one by one, adding them to the input string until it reaches the end of the serial input (ie a null character). For some reason the 'if' statement won't execute for

inChar == '\0'

But if I replace '\0' with an arbitrary character as in

inChar == 'g'

It executes just fine. Am I somehow calling the null character '\0' wrong?

What you want is read word by word, or letter by letter and determine the end of the entire message? — rendon
– rendon, Commented Dec 18, 2012 at 0:46
Yeah, something like that. The function reads each incoming character and appends it to String input. When it finds a null character I want stringComplete to be true, which is the cue for a separate function to take over. — GoatFood
– GoatFood, Commented Dec 18, 2012 at 1:07
What I think is that you think that you read all characters in the while loop, Am I right? The truth is that only a character is read by each call to the loop() method, so, you can set stringComplete = true when Serial.available() == 0. — rendon
– rendon, Commented Dec 18, 2012 at 1:14

rendon · Accepted Answer · 2012-12-18 01:24:43Z

4

What I think is that you think that you read all characters in the while loop, Am I right? The truth is that only a character is read by each call to the loop() method, so, you can set stringComplete = true when Serial.available() == 0.

answered Dec 18, 2012 at 1:24

rendon

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