Arduino GPS Shield by iteadstudio.com

Using Arduino Programming Questions
30

troyka_4484:
yes the code i attached worked...
now i am trying this TingGPS example

i tried both baud rates 9600 (it was used in the demo) & 38400 the baud rate give in the data sheet..
but all i get is stars....
here's my results :

Testing TinyGPS library v. 12
by Mikal Hart

Sizeof(gpsobject) = 115

Sats HDOP Latitude Longitude Fix Date Time Date Alt Course Speed Card Distance Course Card Chars Sentences Checksum
(deg) (deg) Age Age (m) --- from GPS ---- ---- to London ---- RX RX Fail

**** **** ******* ******* **** ******* ******* **** ******* ****** ***** *** 0 0.00 *** 173 0 0
**** **** ******* ******* **** ******* ******* **** ******* ****** ***** *** 0 0.00 *** 310 0 0
etc...

once again, thank you for your help, Paul :slight_smile:

I don't know if anyone pointed this out to you yet but the reason you are getting stars is because these functions print stars if the data that it gets is invalid:

static void print_int(unsigned long val, unsigned long invalid, int len)
{
  char sz[32];
  if (val == invalid)
    strcpy(sz, "*******");
  else
    sprintf(sz, "%ld", val);
  sz[len] = 0;
  for (int i=strlen(sz); i<len; ++i)
    sz[i] = ' ';
  if (len > 0) 
    sz[len-1] = ' ';
  Serial.print(sz);
  feedgps();
}

static void print_float(float val, float invalid, int len, int prec)
{
  char sz[32];
  if (val == invalid)
  {
    strcpy(sz, "*******");
    sz[len] = 0;
        if (len > 0) 
          sz[len-1] = ' ';
    for (int i=7; i<len; ++i)
        sz[i] = ' ';
    Serial.print(sz);
  }
  else
  {
    Serial.print(val, prec);
    int vi = abs((int)val);
    int flen = prec + (val < 0.0 ? 2 : 1);
    flen += vi >= 1000 ? 4 : vi >= 100 ? 3 : vi >= 10 ? 2 : 1;
    for (int i=flen; i<len; ++i)
      Serial.print(" ");
  }
  feedgps();
}

static void print_date(TinyGPS &gps)
{
  int year;
  byte month, day, hour, minute, second, hundredths;
  unsigned long age;
  gps.crack_datetime(&year, &month, &day, &hour, &minute, &second, &hundredths, &age);
  if (age == TinyGPS::GPS_INVALID_AGE)
    Serial.print("*******    *******    ");
  else
  {
    char sz[32];
    sprintf(sz, "%02d/%02d/%02d %02d:%02d:%02d   ",
        month, day, year, hour, minute, second);
    Serial.print(sz);
  }
  print_int(age, TinyGPS::GPS_INVALID_AGE, 5);
  feedgps();
}

The reason the data is coming up as invalid is because all it is receiving from the GPS is 0xFFFFFFFF which means the GPS is putting out data but it doesn't have enough satellite fixes to output valid data. You can see that the UART is receiving information from the GPS because in your data above you can see the number of characters received go from 173 to 310. Once the GPS gets I believe 4 satellite fixes it will start putting out valid data. Are you testing this inside? Check out this video tutorial....it will help a lot: