Problem with my GPS module NEO-6m

Using Arduino Sensors
1

Hello everyone !

I write this new subject because I have a very specific problem with my GPS module "NEO-6M GY-GPS6MV2".

I started to use this module to get a GPS positon thanks to the RX0 and TX0 pin of my mega2560. After 15 or 20min, i get a GPGLL position (I upload no code on my mega2560 to get this position).

But now, I want to use this code that I found on the internet :

#include <SoftwareSerial.h>

// setup gps serial
int gpsTxPin = 8;
int gpsRxPin = 9;
SoftwareSerial gpsSerial(gpsTxPin, gpsRxPin);

void setup()
{
  Serial.begin(9600);  //set monitor to 9600
 
  gpsSerial.begin(9600); //adjust for GPS unit

  Serial.println("Ready!");
}

void loop()
{
  while(gpsSerial.available())
  {
    char c = gpsSerial.read();
    Serial.print(c);
  }
}

But "gpsSerial.available()" always return 0 and I really don't know why. I do a lot of research on the Internet, verify my wire a multiple of time, connect the VCC pin to the 3,3V of my mega2560 and GND pin of my mega2560 with no success. I don't know why the GPS work with no code on pin RX0 and TX0 but doesn't work on my pin 8 and 9 with SoftwareSerial.

Please if you know what is the problem answer me :slight_smile:

2

Why in the world would you want to use software serial on a Mega that has 3 extra hardware serial ports?

SoftwareSerial gpsSerial(gpsTxPin, gpsRxPin);

The syntax for the software serial constructor is

SoftwareSerial mySerial(RX, TX);

The first parameter is always RX, no matter what name you give it. So which Mega pin is the GPS TX pin connected?

3

Try this code that uses Serial1 instead of software serial. Tested on my Mega with NEO6M on Serial1 (pin 19 = RX1) GPS RX not connected nor necessary.

//gps test
// connect GPS TX to Mega pin 19 (RX1).  GPS RX not connected.

void setup()
{
   // Open serial communications
   Serial.begin(9600);  
   Serial1.begin(9600);
   Serial.print("Mega up");
}

void loop()
{
   if (Serial1.available())
   {
      Serial.print(char(Serial1.read()));
   }
}
4

Good evening groundFungus !

Thank you for your quick answer. I'll do the modification when I'll be back home and give you some news as soon as i can.

5

Donel:
int gpsTxPin = 8;
int gpsRxPin = 9;
SoftwareSerial gpsSerial(gpsTxPin, gpsRxPin);

But "gpsSerial.available()" always return 0 and I really don't know why. I do a lot of research on the Internet

I don't know why the GPS work with no code on pin RX0 and TX0 but doesn't work on my pin 8 and 9 with SoftwareSerial.

Always worth checking the documentation.

So softwareserial is not working on the ATmega, so check the reference, found by a Google search on 'Arduino softwareserial reference' ;

https://www.arduino.cc/en/Reference/softwareSerial

And you will clearly see that softwareserial (receive) will not work on pin 9 on a Mega ...........

But as mentioned, why use softwareserial on the Mega in the first place.

6

Hi and thank you both for your return.

Indeed, I'm a beginner in arduino programmation and I didn't realize that I have a lot of communication pin on my mega2560 (the example that I saw was with an arduino uno). My bad :frowning:

Now I have a lot of NMEA sentences, but do you know how long it takes to have a full correct position ? For the moment I have a lot of sentences but they didn't gave me a postion ( I have a lot of blink inside the sentences).

Thank you very much for your attention

7

Is the GPS outdoors with a clear view of the sky? if not, it is unlikely to get a fix. Mine will get a fix in my home office. The GPS is by a window and my house is one story wood framed and it will take 15 to 30 minutes to get a good fix if I haven't used it in a few weeks.

8

Donel:
Now I have a lot of NMEA sentences, but do you know how long it takes to have a full correct position ?

If the GPS is outdoors, with a good view of the sky, then if its working correctly, it should get a fix in 45 to 60 seconds.

Thats from cold, new and direct out of the factory.

If it takes longer the GPS or its antenna are faulty.