Sending GPS data between two Arduinos using Easy Transfer

Question

I'm trying to get GPS data transmitted from one Arduino UNO to a second unit to eventually be displayed on an LCD and stored in an SD card. I am using Xbees S2C's on Xbee Shield's to do this. The GPS information is coming from an Adafruit ultimate GPS breakout.

First I wanted so send two NMEA sentences as strings, but have since found that the EasyTransfer library does not like that. I was getting information but it was just random characters, sort of. The pattern was repeated, so it was consistent.

After doing some searching I thought the best way to do it was to convert my strings to character arrays and send those. I managed to successfully convert them to character arrays, but I can't seem to get them over to the other Arduino. I do get the FIX int as well as the Length int that I sent over just to make sure it is working. Any ideas on what I am doing wrong?

Sender code:

#include <EasyTransfer.h>
#include <Adafruit_GPS.h>
#include <SoftwareSerial.h> 
SoftwareSerial mySerial(3, 2); //Initialize SoftwareSerial, and tell it you will be connecting through pins 2 and 3
Adafruit_GPS GPS(&mySerial); //Create GPS object
String NMEA1; //We will use this variable to hold our first NMEA sentence
String NMEA2; //We will use this variable to hold our second NMEA sentence
char c; //Used to read the characters spewing from the GPS module
int fix = 0;
long GPStime = 0;
int val = 0;
EasyTransfer ET;
//Declare Data Structure for the EasyTransfer Library
//Note: Data Structure must be same on TX and RX...
struct DATA_STRUCTURE{
 int fixed;
 int length1;
 int length2;
 char* nmea1;
 char* nmea2;
};
DATA_STRUCTURE myData;
void setup()
{
 //Initalizing EasyTransfer Serial Ports
 Serial.begin(115200);
 ET.begin(details(myData), &Serial);
 GPS.begin(9600); //Turn GPS on at baud rate of 9600
 pinMode(13, OUTPUT);
 digitalWrite(13, LOW);
 //Serial.println("Two GPS Sentences From GPS");
 GPS.sendCommand("$PGCMD,33,0*6D"); // Turn Off GPS Antenna Update
 GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA); //Tell GPS we want only $GPRMC and $GPGGA NMEA sentences
 GPS.sendCommand(PMTK_SET_NMEA_UPDATE_10HZ); // 10 Hz update rate
 delay(1000); //Pause
}
void loop()
{
 readGPS(); //This is a function we define below which reads two NMEA sentences from GPS
 //Sending Data
 ET.sendData();
}
void readGPS() //This function will read and remember two NMEA sentences from GPS
{ 
 clearGPS(); //Serial port probably has old or corrupt data, so begin by clearing it all out
 while(!GPS.newNMEAreceived()) //Keep reading characters in this loop until a good NMEA sentence is received
 { 
 c=GPS.read(); //read a character from the GPS
 }
 GPS.parse(GPS.lastNMEA()); //Once you get a good NMEA, parse it
 NMEA1=GPS.lastNMEA(); //Once parsed, save NMEA sentence into NMEA1
 while(!GPS.newNMEAreceived()) //Go out and get the second NMEA sentence, should be different type than the first one read above.
 { 
 c=GPS.read();
 }
 GPS.parse(GPS.lastNMEA());
 NMEA2=GPS.lastNMEA();
 fix = GPS.fix;
 if (fix == 1)
 {
 //Serial.print("FIXED");
 digitalWrite(13, HIGH);
 //Serial.print(NMEA1);
 myData.fixed = 1;
 int str_len1 = NMEA1.length();
 char char_array1[str_len1];
 NMEA1.toCharArray(char_array1, str_len1);
 myData.length1 = str_len1;
 //Serial.print(char_array1);
 //Serial.println("");
 //Serial.println("");
 myData.nmea1 = char_array1;
 }
 else
 {
 //Serial.println("No fix");
 digitalWrite(13, LOW);
 myData.fixed = 0;
 }
}
void clearGPS() //Since between GPS reads, we still have data streaming in, we need to clear the old data by reading a few sentences, and discarding these
{ 
 while(!GPS.newNMEAreceived()) 
 {
 c=GPS.read();
 }
 GPS.parse(GPS.lastNMEA());
 while(!GPS.newNMEAreceived()) 
 {
 c=GPS.read();
 }
 GPS.parse(GPS.lastNMEA());
}

Receiver Code:

#include <EasyTransfer.h>
#include "Wire.h"
#include "Adafruit_LiquidCrystal.h"
EasyTransfer ET;
Adafruit_LiquidCrystal lcd(0);
//Declare Data Structure for the EasyTransfer Library
//Note: Data Structure must be same on TX and RX...
struct DATA_STRUCTURE{
 int fixed;
 int length1;
 int length2;
 char* nmea1;
 char* nmea2;
 //int pause;
};
DATA_STRUCTURE myData;
char* NMEA1[100] = {0};
void setup()
{
 //Initalizing EasyTransfer Serial Ports
 Serial.begin(115200);
 ET.begin(details(myData), &Serial);
 lcd.begin(20, 4);
 lcd.clear();
 lcd.setBacklight(HIGH);
 pinMode(13, OUTPUT);
 digitalWrite(13, LOW);
}
void loop()
{
 //check and see if a data packet has come in. 
 if(ET.receiveData()){
 //this is how you access the variables. [name of the group].[variable name]
 int FIX = myData.fixed;
 int LENGTH1 = myData.length1;
 char* NMEA1 = myData.nmea1;
 Serial.println(FIX);
 Serial.println(LENGTH1);
 Serial.print(NMEA1);
 Serial.println("");
 if (myData.fixed == 1)
 {
 digitalWrite(13, HIGH);
 lcd.setCursor(10, 3);
 lcd.print(" GPS Fixed");
 }
 else
 {
 digitalWrite(13, LOW);
 lcd.setCursor(10, 3);
 lcd.print("No GPS Fix");
 }
 }
 delay(1000);
}

Any help would be appreciated.

Thanks! K-Bert

• Majenko: Possible duplicate of Casting a struct member between uint8_t and char, with regard to serial transfer