I am using an Arduino Mega 2560. The shield is mounted. There is no external antenna; I have a weight limit for the instrument.
A. The Direct comm test appears to work, although no data is present (lots of empty fields in the displayed Serial console).
B. I then moved to the SoftwareSerial test. I know that the Mega does not have TX/Rcv on pins 7&8. I am using pins 18&19:
SoftwareSerial mySerial(18, 19);
When it runs, it never gets a fix. I have tried it indoors and outdoors, letting it sit for 30-40 minutes without ever getting a fix. The red light on the shield flashes every second or so, apparently when it tries to get a fix.
Attached is the code - basically the SoftTest example program.
1) I don't know where to start to make this shield work. Perhaps there is some other issue related to the Mega? I understand that other people have used this on a Mega...
2) I read (I think in the tutorial) that the sensor will not work indoors. Won't the radio signal go indoors? Is there some other problem preventing it from working indoors? My application will be sending it up in essentially a small styrofoam box attached to a weather balloon to 100,000 feet. Is there some reason the GPS would not get a fix inside a foam box?
Thanks for any help/clues:)
Code:
Code: Select all
// Test code for Adafruit GPS modules using MTK3329/MTK3339 driver
//
// This code shows how to listen to the GPS module in an interrupt
// which allows the program to have more 'freedom' - just parse
// when a new NMEA sentence is available! Then access data when
// desired.
//
// Tested and works great with the Adafruit Ultimate GPS module
// using MTK33x9 chipset
// ------> http://www.adafruit.com/products/746
// Pick one up today at the Adafruit electronics shop
// and help support open source hardware & software! -ada
#include <Adafruit_GPS.h>
#include <SoftwareSerial.h>
// Connect the GPS Power pin to 5V
// Connect the GPS Ground pin to ground
// Connect the GPS TX (transmit) pin to Digital 8
// Connect the GPS RX (receive) pin to Digital 7
// you can change the pin numbers to match your wiring:
SoftwareSerial mySerial(18, 19); // Tx, Rcv
Adafruit_GPS GPS(&mySerial);
// Set GPSECHO to 'false' to turn off echoing the GPS data to the Serial console
// Set to 'true' if you want to debug and listen to the raw GPS sentences
#define GPSECHO true
void setup()
{
// connect at 115200 so we can read the GPS fast enough and echo without dropping chars
// also spit it out
Serial.begin(115200);
delay(5000);
Serial.println("Adafruit GPS library basic parsing test!");
// 9600 NMEA is the default baud rate for Adafruit MTK GPS's- some use 4800
GPS.begin(9600);
// uncomment this line to turn on RMC (recommended minimum) and GGA (fix data) including altitude
GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCGGA);
// uncomment this line to turn on only the "minimum recommended" data
//GPS.sendCommand(PMTK_SET_NMEA_OUTPUT_RMCONLY);
// For parsing data, we don't suggest using anything but either RMC only or RMC+GGA since
// the parser doesn't care about other sentences at this time
// Set the update rate
GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ); // 1 Hz update rate
// For the parsing code to work nicely and have time to sort thru the data, and
// print it out we don't suggest using anything higher than 1 Hz
// Request updates on antenna status, comment out to keep quiet
GPS.sendCommand(PGCMD_ANTENNA);
delay(1000);
// Ask for firmware version
mySerial.println(PMTK_Q_RELEASE);
}
uint32_t timer = millis();
void loop() // run over and over again
{
char c = GPS.read();
// if you want to debug, this is a good time to do it!
if ((c) && (GPSECHO))
Serial.write(c);
// if a sentence is received, we can check the checksum, parse it...
if (GPS.newNMEAreceived()) {
// a tricky thing here is if we print the NMEA sentence, or data
// we end up not listening and catching other sentences!
// so be very wary if using OUTPUT_ALLDATA and trytng to print out data
//Serial.println(GPS.lastNMEA()); // this also sets the newNMEAreceived() flag to false
if (!GPS.parse(GPS.lastNMEA())) // this also sets the newNMEAreceived() flag to false
return; // we can fail to parse a sentence in which case we should just wait for another
}
// approximately every 2 seconds or so, print out the current stats
if (millis() - timer > 2000) {
timer = millis(); // reset the timer
Serial.print("\nTime: ");
if (GPS.hour < 10) { Serial.print('0'); }
Serial.print(GPS.hour, DEC); Serial.print(':');
if (GPS.minute < 10) { Serial.print('0'); }
Serial.print(GPS.minute, DEC); Serial.print(':');
if (GPS.seconds < 10) { Serial.print('0'); }
Serial.print(GPS.seconds, DEC); Serial.print('.');
if (GPS.milliseconds < 10) {
Serial.print("00");
} else if (GPS.milliseconds > 9 && GPS.milliseconds < 100) {
Serial.print("0");
}
Serial.println(GPS.milliseconds);
Serial.print("Date: ");
Serial.print(GPS.day, DEC); Serial.print('/');
Serial.print(GPS.month, DEC); Serial.print("/20");
Serial.println(GPS.year, DEC);
Serial.print("Fix: "); Serial.print((int)GPS.fix);
Serial.print(" quality: "); Serial.println((int)GPS.fixquality);
if (GPS.fix) {
Serial.print("Location: ");
Serial.print(GPS.latitude, 4); Serial.print(GPS.lat);
Serial.print(", ");
Serial.print(GPS.longitude, 4); Serial.println(GPS.lon);
Serial.print("Speed (knots): "); Serial.println(GPS.speed);
Serial.print("Angle: "); Serial.println(GPS.angle);
Serial.print("Altitude: "); Serial.println(GPS.altitude);
Serial.print("Satellites: "); Serial.println((int)GPS.satellites);
}
}
}