Cleaned up some comments. Augmented the README.md

.gitignore

@@ -1,3 +1,6 @@
+# Emacs backups
+*~
+
 # Compiled Object files
 *.slo
 *.lo

APRSExample.cpp

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+// Example program for the APRS code in this repository
+
+/*
+ * Copyright (C) 2014 by Richard Nash (KC3ARY)
+ * 
+ * This program 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 this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include <WProgram.h>
+// Note: this example uses my GPS library for the Adafruit Ultimate GPS
+// Code located here: https://github.com/rvnash/ultimate_gps_teensy3
+#include <GPS.h>
+#include <aprs.h>
+
+// APRS Information
+#define PTT_PIN 13 // Push to talk pin
+
+// Set your callsign and SSID here. Common values for the SSID are
+#define S_CALLSIGN      "KC3ARY"
+#define S_CALLSIGN_ID   1   // 11 is usually for balloons
+// Destination callsign: APRS (with SSID=0) is usually okay.
+#define D_CALLSIGN      "APRS"
+#define D_CALLSIGN_ID   0
+// Symbol Table: '/' is primary table '\' is secondary table
+#define SYMBOL_TABLE '/' 
+// Primary Table Symbols: /O=balloon, /-=House, /v=Blue Van, />=Red Car
+#define SYMBOL_CHAR 'v'
+
+struct PathAddress addresses[] = {
+  {(char *)D_CALLSIGN, D_CALLSIGN_ID},  // Destination callsign
+  {(char *)S_CALLSIGN, S_CALLSIGN_ID},  // Source callsign
+  {(char *)NULL, 0}, // Digi1 (first digi in the chain)
+  {(char *)NULL, 0}  // Digi2 (second digi in the chain)
+};
+
+
+HardwareSerial &gpsSerial = Serial1;
+GPS gps(&gpsSerial,true);
+
+// setup() method runs once, when the sketch starts
+void setup()
+{
+  Serial.begin(38400); // For debugging output over the USB port
+  gps.startSerial(9600);
+  delay(1000);
+  gps.setSentencesToReceive(OUTPUT_RMC_GGA);
+
+  // Set up the APRS module
+  aprs_setup(200, // ms to transmit ax25 flag
+	     PTT_PIN, // Use PTT pin
+	     100, // ms to wait after PTT to transmit
+	     0, 0 // No VOX ton
+	     );
+}
+
+// Function to broadcast your location
+void broadcastLocation(GPS &gps, const char *comment)
+{
+  // If above 5000 feet switch to a single hop path
+  int nAddresses;
+  if (gps.altitude > 1500) {
+    // APRS recomendations for > 5000 feet is:
+    // Path: WIDE2-1 is acceptable, but no path is preferred.
+    nAddresses = 3;
+    addresses[2].callsign = "WIDE2";
+    addresses[2].ssid = 1;
+  } else {
+    // Below 1500 meters use a much more generous path (assuming a mobile station)
+    // Path is "WIDE1-1,WIDE2-2"
+    nAddresses = 4;
+    addresses[2].callsign = "WIDE1";
+    addresses[2].ssid = 1;
+    addresses[3].callsign = "WIDE2";
+    addresses[3].ssid = 2;
+  }
+
+  // For debugging print out the path
+  Serial.print("APRS(");
+  Serial.print(nAddresses);
+  Serial.print("): ");
+  for (int i=0; i < nAddresses; i++) {
+    Serial.print(addresses[i].callsign);
+    Serial.print('-');
+    Serial.print(addresses[i].ssid);
+    if (i < nAddresses-1)
+      Serial.print(',');
+  }
+  Serial.print(' ');
+  Serial.print(SYMBOL_TABLE);
+  Serial.print(SYMBOL_CHAR);
+  Serial.println();
+
+  // Send the packet
+  aprs_send(addresses, nAddresses
+	    ,gps.day, gps.hour, gps.minute
+	    ,gps.latitude, gps.longitude // degrees
+	    ,gps.altitude // meters
+	    ,gps.heading
+	    ,gps.speed
+	    ,SYMBOL_TABLE
+	    ,SYMBOL_CHAR
+	    ,comment);
+}
+
+uint32_t timeOfAPRS = 0;
+bool gotGPS = false;
+// the loop() methor runs over and over again,
+// as long as the board has power
+void loop()
+{
+  if (gps.sentenceAvailable()) gps.parseSentence();
+
+  if (gps.newValuesSinceDataRead()) {
+    gotGPS = true; // @TODO: Should really check to see if the location data is still valid
+    gps.dataRead();
+    Serial.printf("Location: %f, %f altitude %f\n\r",
+		  gps.latitude, gps.longitude, gps.altitude);
+  }
+
+  if (gotGPS && timeOfAPRS + 60000 < millis()) {
+    broadcastLocation(gps, "HELLO" );
+    timeOfAPRS = millis();
+  }
+}
+
+// Called from the powerup interrupt servicing routine.
+int main(void)
+{
+  setup();
+  while (true) {
+    loop();
+    yield();
+  }
+  return 0; // Never reached.
+}