The set up of the mote is very simple, we plug the GPS module to SquidBee mote with two cables to power the GPS board (Red cable for 5V and black cable for ground), inside the SquidBee enclosure we have to put an internal active GPS antenna (included with the GPS module). And SquidBee is  ready for reading data coming from the GPS module. Just a small change in the SquidBee program is needed for getting the data from GPS module. (see code above).

Once we have the SquidBee mote programmed and the GPS board plugged, we connect the 9V battery. Our SquidBee mote with GPS will take around one minute to get connected to the satellites, when SquidBee get a good quality of signal from satellites it will start to provide the RMC sentences witch contains data of coordinates, speed, UTC (universal time coordinated), elevation... It's easy to modify the code above to get another NMEA sentences.

Here is an example of the NMEA sentences

$GPGLL,0000.000,N,00000.000,E,000243.000,V*26
$GPGGA,000244.000,0000.00000,N,00000.00000,E,0,00,99.0,082.00,M,18.0,M,,*5C
$GPVTG,0.0,T,,M,0.0,N,0.0,K*60
$GPGSA,A,1,,,,,,,,,,,,,99.0,99.0,99.0*00

More NMEA info

 

/*
 * Copyright (C) 2008 Libelium Comunicaciones Distribuidas S.L.
 *
 * This file is part of SquidBee code examples
 * squidbee_GPS.pde is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 *You should have received a copy of the GNU General Public License
 *along with Foobar.  If not, see <http://www.gnu.org/licenses/>.
 */

/* Name: squidbee_GPS.pde
 * Version 0.0.1
 * Desc: A GPS module is attached to SquidBee as a new sensor
 * Author: Marcos Yarza <m.yarza"at/removethis"libelium.com>
 */

// include the SoftwareSerial library
#include <SoftwareSerial.h>

// Constants
#define rxPin 9      //rx pin in gps connection
#define txPin 8      //tx pin in gps connection

// set up the serial port

SoftwareSerial gps = SoftwareSerial(rxPin, txPin);

// variables
byte byteGPS = 0;
int i = 0;
int count = 0;
int h = 0;

// Buffers for data input
char inBuffer[300] = "";
char GPS_sentence[100]="";

//variables for sensors

int sens0 = 0;    //sensors
int sens1 = 1;
int sens2 = 2;

int val0 = 0;    //aux var
int val1 = 0;
int val2 = 0;

// function to send data

void sendData(int id,int num, int data0,int data1,int data2,char GPS_sentence[]){
  
  Serial.print("@");
  Serial.print(id);
  Serial.print("|");
  
  Serial.print(num);
  
  Serial.print("|data0-");
  Serial.print(data0);
  
  Serial.print("|data1-");
  Serial.print(data1);
  
  Serial.print("|data2-");
  Serial.print(data2);
  
  Serial.print("|GPS_sentence-");
  h = 0;
  while(GPS_sentence[h] != 42){
    Serial.print(GPS_sentence[h]);
    h++;
  }
  
  Serial.println("#r");      // end of message
}

void setup(){

  //setup for mySerial port
  pinMode(rxPin, INPUT);
  pinMode(txPin, OUTPUT);
  gps.begin(4800);
  
  //setup for Serial port
  Serial.begin(19200);

  // setup the GPS module
  Serial.println("Configurando GPS...");
  delay(1000);
  gps.println("$PSTMNMEACONFIG,0,4800,64,1");        // configure NMEA sentences to show only RMC                                                                                                                                                                                                                                 
                                                                                           
  delay(100);
  
  // command for setting time and position
  gps.println("$PSTMINITGPS,4140.000,N,00053.000,W,0197,22,10,2007,11,40,00");    

  // "4140.000,N" means: Latitude 41º40'00.0" North
  // "00053.000,W" means: Longitude 0º53'00.0" West
  // "0197" means 197 m elevation
  // "22,10,2007,11,40,00" means date and time (October 22, 2.007 - 11h 40min 00sec UTC time)
}

void loop(){
 
  val0 = analogRead(sens0);
  val1 = analogRead(sens1);
  val2 = analogRead(sens2);

  
  byteGPS = 0;
  i = 0;
  while(byteGPS != 42){                   // read the GGA sentence
    byteGPS = gps.read();         
    inBuffer[i]=byteGPS;
    GPS_sentence[i]=byteGPS;    
    i++;                      
  }
  
  sendData(1,count, val0,val1,val2,GPS_sentence);
  
  count++;
  
  delay(5000);
}