// SuperBeacon v1.2 - James Coxon http://www.pegasushabproject.org.uk
// Designed for a EM406a, Arduino Mini Pro and a Circuit Design CDP-TX-04S-R Radio
// Reads the GPS, Parses, keys out the lat, lon and alt and then acts like a beacon for 3 mins
//
// GPS read and parsing based on ladyada's code
// see http://www.ladyada.net/make/gpsshield for more info
 
#include <stdlib.h>    
#include <string.h>
 
#define GPSRATE 4800
 
// GPS parser for 406a
#define BUFFSIZ 90 // plenty big
char buffer[BUFFSIZ];
char buffidx, test;
 
char *GGAtime, *GGAlat, *GGAlatdir, *GGAlon, *GGAlondir, *GGAalt, *token;
 
int x, n, z, nBeeps;
int p = 0;
 
void setup() 
{ 
  pinMode(4, OUTPUT);
  pinMode(13, OUTPUT);
  Serial.begin(GPSRATE);
 
  // prints title with ending line break 
  Serial.println("GPS Beacon"); 
  Serial.println("Based on ladayada's GPS Parser"); 
  digitalWrite(4, HIGH);   // sets the Radio on
  digitalWrite(13, HIGH);   // sets the LED on
  delay(1500);
  digitalWrite(4, LOW);    // sets the Radio off
    digitalWrite(13, LOW);   // sets the LED off
  delay(500);
} 
 
void loop(){
  while ( p < 7 ){
  Serial.println("Checking GPS");
  readline();
  p++;
  // check if $GPGGA (global positioning fixed data)
  if (strncmp(buffer, "$GPGGA",6) == 0) {
    p = 10;
    char * ptr;
    token = strtok_r(buffer, ",",&ptr);
    token = strtok_r(NULL, ",",&ptr);
    GGAtime = token;
    Serial.println(GGAtime);
    token = strtok_r(NULL, ",",&ptr);
    GGAlat = token;
    Serial.println(GGAlat);
    token = strtok_r(NULL, ",",&ptr);
    GGAlatdir = token;
    Serial.println(GGAlatdir);
    token = strtok_r(NULL, ",",&ptr);
    GGAlon = token;
    Serial.println(GGAlon);
    token = strtok_r(NULL, ",",&ptr);
    GGAlondir = token;
    Serial.println(GGAlondir);
    token = strtok_r(NULL, ",",&ptr);
    token = strtok_r(NULL, ",",&ptr);
    token = strtok_r(NULL, ",",&ptr);
    token = strtok_r(NULL, ",",&ptr);
    GGAalt = token;
    Serial.println(GGAalt);
 
    x = strlen(GGAlat);
    for ( n=0 ; n<x ; n++ )
    {
    Serial.println(GGAlat[n]);
    test = GGAlat[n];
    nBeeps = atoi(&test);
    Serial.println(nBeeps);
    for ( z=0 ; z<nBeeps ; z++)
      {
        digitalWrite(4, HIGH);   // sets the Radio on
        digitalWrite(13, HIGH);   // sets the LED on
         delay(500);
        digitalWrite(4, LOW);    // sets the Radio off
        digitalWrite(13, LOW);   // sets the LED off
        delay(500);
 
      }
    if ( nBeeps == 0 )
      {
        Serial.println("Got a 0");
        digitalWrite(4, HIGH);   // sets the Radio on
          digitalWrite(13, HIGH);   // sets the LED on
         delay(1500);
        digitalWrite(4, LOW);    // sets the Radio off
        digitalWrite(13, LOW);   // sets the LED off
        delay(500);
      }
    delay(3000);
    }
 
    x = strlen(GGAlon);
    for ( n=0 ; n<x ; n++ )
    {
    Serial.println(GGAlon[n]);
    test = GGAlon[n];
    nBeeps = atoi(&test);
    Serial.println(nBeeps);
    for ( z=0 ; z<nBeeps ; z++)
      {
        digitalWrite(4, HIGH);   // sets the Radio on
          digitalWrite(13, HIGH);   // sets the LED on
         delay(500);
        digitalWrite(4, LOW);    // sets the Radio off
        digitalWrite(13, LOW);   // sets the LED off
        delay(500);
 
      }
    if ( nBeeps == 0 )
      {
        Serial.println("Got a 0");
        digitalWrite(4, HIGH);   // sets the Radio on
          digitalWrite(13, HIGH);   // sets the LED on
         delay(1500);
        digitalWrite(4, LOW);    // sets the Radio off
        digitalWrite(13, LOW);   // sets the LED off
        delay(500);
      }
    delay(3000);
    }
 
    x = strlen(GGAalt);
    for ( n=0 ; n<x ; n++ )
     {
    Serial.println(GGAalt[n]);
    test = GGAalt[n];
    nBeeps = atoi(&test);
    Serial.println(nBeeps);
    for ( z=0 ; z<nBeeps ; z++)
      {
        digitalWrite(4, HIGH);   // sets the Radio on
          digitalWrite(13, HIGH);   // sets the LED on
         delay(500);
        digitalWrite(4, LOW);    // sets the Radio off
        digitalWrite(13, LOW);   // sets the LED off
        delay(500);
 
      }
    if ( nBeeps == 0 )
      {
        Serial.println("Got a 0");
        digitalWrite(4, HIGH);   // sets the Radio on
          digitalWrite(13, HIGH);   // sets the LED on
         delay(1500);
        digitalWrite(4, LOW);    // sets the Radio off
        digitalWrite(13, LOW);   // sets the LED off
        delay(500);
      }
    delay(3000);
    }
 
  }
  }
  Serial.println("Beacon for 3 minutes");
  p = 0;
  for ( z=0 ; z<40 ; z++)
    {
   digitalWrite(4, HIGH);   // sets the Radio on
     digitalWrite(13, HIGH);   // sets the LED on
   delay(3000);
   digitalWrite(4, LOW);    // sets the Radio off
   digitalWrite(13, LOW);   // sets the LED off
   delay(1500);
    }
}
 
void readline(void) {
  char c;
  buffidx = 0; // start at begeninning
  while (1) {
      c=Serial.read();
      if (c == -1)
        continue;
      Serial.print(c);
      if (c == '\n')
        continue;
      if ((buffidx == BUFFSIZ-1) || (c == '\r')) {
        buffer[buffidx] = 0;
        return;
      }
      buffer[buffidx++]= c;
  }
}