Advanced Input, sparkfun usb weather board. by BARRAGAN http://barraganstudio.com

Demonstrates how to read data from the sparkfun usb weather board using the Serial library. The weather board includes temperature, humidity and barometric pressure. The weather board is connected to the Serial1 serial port.

String weatherSentence = "";  // string to read data from the weather board
int ready = 0;                // used to mark when we have a complete string to process
char data;                    // use to read a byte from the serial
char charArray[100];          // create a char 100 position char array por parsing the data

unsigned long humidity = 0, fahrenheit = 0, celcius = 0, SCPfahrenheit = 0, presure = 0;

void setup()
{
  Serial1.begin(9600);   // starts the second hardware serial port at 9600 to communicate with the weather board
  Serial.begin(9600);    // starts the serial at 9600
  pinMode(WLED, OUTPUT); // turn ON the board LED for diagnostics
  digitalWrite(WLED, HIGH);
}

void loop()
{
  while (Serial1.available() > 0)  // if data vailable from the weather board
  {
    data = Serial1.read();         // read it
    if ((data != '\n'))            // if no end of line
    {
      weatherSentence += data;     // add it to the string
    }
    else    // if end of line reached, readu to parse the buffer
    {
      ready = 1;
      break;
    }
  }
  if (ready == 1)  // parse the buffer
  {
    if (weatherSentence.startsWith("#"))  // verify if it is a good reading
    {
      // uncomment just to see what we got
      // Serial.println(buffer);
      weatherSentence.toCharArray(charArray, 100); // get the characters copied into charArray of size 100
      processReading(charArray); // parse the char array extracting the data
    }
    weatherSentence = ""; // clean up the string for next reading
    ready = 0;
  }
}

// function that parses information received in a char array
void processReading(const char packet[])
{
  byte i;
  char* endptr;

  // start parsing
  i = 0;
  i++;
  humidity = strtod(&packet[i], &endptr);  // next field: humidity

  while (packet[i++] != ',');      // next field: fahrenheit
  fahrenheit = strtod(&packet[i], &endptr);

  while (packet[i++] != ',');      // next field: celcius
  celcius = strtod(&packet[i], &endptr);

  while (packet[i++] != ',');      // next field: SCPfahrenheit
  SCPfahrenheit = strtod(&packet[i], &endptr);

  while (packet[i++] != ',');            // next field: presure
  presure = strtod(&packet[i], &endptr);

  while (packet[i++] != ',');      // next field: counter

  while (packet[i++] != '$');      // next field: checksum

  Serial.print("humidity: ");
  Serial.print(humidity, DEC);
  Serial.print(" fahrenheit: ");
  Serial.print(fahrenheit, DEC);
  Serial.print(" celcius: ");
  Serial.print(celcius, DEC);
  Serial.print(" SCPfahrenheit: ");
  Serial.print(SCPfahrenheit, DEC);
  Serial.print(" presure: ");
  Serial.println(presure, DEC);
}