How to retrieve a String value from Serial.read();

Question

I am trying to send an SMS that contains multiple values as a String, which then will be received by the Arduino board as a Serial.read(); command. For example, if i where to send the following SMS to the board, "Username PhoneNumber Email". The code will then receive the SMS and divides it into different String values, which i can then use in the code.

So far i have been able to do all of that, the issue that i am currently facing, is that i can seem to receive the text message as a String value, which means that the board is not receiving it as a String, instead it is receiving it as char[].

in result, i am getting the following output when i try to print out the value,

> 1: U
2: 
3: 
1: s
2: 
3: 
1: e
2: 
3: 
1: r
2: 
3: 
1: n
2: 
3: 
1: ame
2: PhoneNu
3: 
1: mber
2: Email
3:

what i want is to get this output,

1:UserName 
2:PhoneNumber 
3:Email

The following is the code i am using:

void setup()
{ 
  Serial.begin(9600); 
}

void loop()
{
  if(Serial.available()>0)
  {
char string[100];
char byteRead;

int availableBytes = Serial.available();
for(int i=0; i<availableBytes; i++)
{
    string[i] = Serial.read();
    string[i+1] = '\0'; // Append a null
} 

String dj = string;
  //char inchar=Serial.read();
  String split= dj;
  String word1 = getValue(split, ' ', 0);
  Serial.println("1: "+word1);
  String word2 = getValue(split, ' ', 1);
  Serial.println("2: "+word2);
  String word3 = getValue(split, ' ', 2);
  Serial.println("3: "+word3);
  }
}
 String getValue(String data, char separator, int index)
{
  int found = 0;
  int strIndex[] = {0, -1};
  int maxIndex = data.length()-1;

  for(int i=0; i<=maxIndex && found<=index; i++){
    if(data.charAt(i)==separator || i==maxIndex){
        found++;
        strIndex[0] = strIndex[1]+1;
        strIndex[1] = (i == maxIndex) ? i+1 : i;
    }
  }

  return found>index ? data.substring(strIndex[0], strIndex[1]) : "";
}

I want the userName to go into String 1, PhoneNumber into String 2 and Email into String 3.

Thank you!! :D

look http://stackoverflow.com/questions/5697047/convert-serial-read-into-a-useable-string-using-arduino — Jayesh Bhoi, Jul 21 '14 at 05:40

score 1 · Answer 1 · answered Jul 21 '14 at 06:12

Your code assumes/requires that all of the data is already available on the serial port when you call loop(). Probably it is not.

From the code that you posted it seems that you must be calling the loop() function repetitively. This, combined with the possibility that only a small amount of the data is actually available at each read, results in the output that you show.

Is there a termination character (e.g. new line) that you can use to determine the end of an SMS record? Can you add one? If so then you may be able to use readBytesUntil() to read input from the serial port until you see the terminator (or a timeout or buffer filled). You might need to call this a few times to accumulate the full SMS record before parsing it in getValue()

How to retrieve a String value from Serial.read();

1 Answers1