Keypad Library... Returning a string after user pressed a certain character

Projects Programming
10

This will read keys until either 6 have been entered each followed by Return, or you enter an F followed by Return

char buffer[7];
char newChar;
int i;

#define NO_KEY '!'

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

void loop()
{
  i = 0;
  buffer[0] = '\0';  //terminator in first position just in case
  while (i < sizeof(buffer) - 1)  //leave space for terminator
  {
    newChar = getChar();
    if (newChar == 'F') 
    {
      break;
    }
    else if (newChar != NO_KEY)
    {
      buffer[i] = newChar;
      i++;
      buffer[i] =  '\0'; //terminate string in case we finish next time
    }
  }
  Serial.println(buffer);
}

char getChar()
{
  if (Serial.available() == 0 )
  {
    newChar = NO_KEY;
  }
  else
  {
    newChar = Serial.read();
  }
  return newChar;
}

I don't have a keypad so it reads input from the serial port. Set the monitor to no termination if you try it.

NOTE - the routine as written is not bullet proof and is quite happy to accept F as the first character as well as a string longer than 6 characters from the serial input with no Return after each but it illustrates the concept of terminating input on receipt of a particular character.