GPS module Fastrax uPatch100, problem

[GaryP]

I have a strange problem. Every now and then, when I start serial monitor, this module sends data nicely, and sometimes not. I have checked it with oscilloscope, and it confirms that when the data is not coming,Tx-signal is sending only random pulses, instead of clear serial data.

What I need to do, is simply cut the VCC and connect it again, and the game goes on.

I have connected the module to Arduino Mega, so I don't have to use software based serial. Module send good 3V signals (when it does) and mega talks back with 5V.

Here is the link for the modules datasheet.

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Too bad this one don't have external reset pin, other model, 100s, that does.

Here is the code for testing

char gps_byte = 0;

void setup(void)
 {
   Serial3.begin(9600);
   Serial.begin(9600); 
   Serial.print("Program started");
 }

void loop(void)
 {
  gps_byte = Serial3.read();

  if (gps_byte != -1)    
    {                    
     if (gps_byte == '

Also, I have tested the module with +3.3 and +5 Vcc, no change.

Connections are simply:
+Vcc
GND
(GPS TX) pin2 - (Mega serial3 Rx) pin 15
(GPS RX) pin3 - (Mega serial3 Tx) pin 14
(GPS Vbat) pin6 - +Vcc

Well, last night was again a long one with searching the solution, now I must ask from pro's...
Thanks!

Cheers,
Kari)
     {
        //What_ever_code_here
     }
      Serial.print(gps_byte);
   }
}

Also, I have tested the module with +3.3 and +5 Vcc, no change.

Connections are simply:
+Vcc
GND
(GPS TX) pin2 - (Mega serial3 Rx) pin 15
(GPS RX) pin3 - (Mega serial3 Tx) pin 14
(GPS Vbat) pin6 - +Vcc

Well, last night was again a long one with searching the solution, now I must ask from pro's...
Thanks!

Cheers,
Kari

[GaryP]

Additional info... I update the previous post as well.

Pin 6 on GPS is tied to VCC, forget that while in my busy morning routines. And I tried to reconnect that when the problem occurs, it is possible that controlling Vbat signal could help, that would be easy fix. I don't know if I lost something by doing that, but need to try.

Kari

[GaryP]

Confirm, added Digital pin2 from arduino to control Vbat. Module will lost its last information, but in my application it's no a problem.

Here's the final minimal code. Feel free to comment, and make it more simple.
Thanks.

char gps_byte = 0;
#define Vbat 2 //digital pin2 to control GPS Vbat, simple reset function???

void setup(void)
 {
   pinMode(Vbat, OUTPUT);
   digitalWrite(Vbat,HIGH);
   delay(100);

   Serial3.begin(9600);
   Serial.begin(9600); 
   Serial.print("Program started");
 }

void loop(void)
 {
  gps_byte = Serial3.read();

  if (gps_byte != -1)    
    {                    
     if (gps_byte == '

Kari)
      {
        //What_ever_code_here
      }
      Serial.print(gps_byte);
    }
}

Kari

[system]

I had the same problem, first couple of NMEA messages mostly ok, then garbage and nothing.
I didn't need to set anything on my uPatch so I didn't connect RX to anything. But after setting RX to ground it works perfectly. Try that.

[GaryP]

Ok, I'll give it a try. And I will report after tests.

BTW, why there is serial talk both ways, to and from GPS module? Is there some commands that can be use to achieve something usefull?
Thanks!

Cheers,
Kari

[system]

HI
I'm developping an object using geolocalisation. For now i use EM 406A with arduino. I'm using the tiny GPS library which make everything very easy.
I need to make this project cheaper (in order to make a lot of this object for an exhibition in Paris)
So i'm very interesting with the uPatch100 because of his price (EM406A cost more than $50...)
I discoverd uPatch100 on onion and garlic blog, guess i'm talking to the author on this post : )

I'm only a designer and my knowledge in electronic is poor, but i need to do it by myself because i don't have any financial help for this projet.
So I wonder if this module is as easy to use as the EM 406A, with a library such as tinyGPS or something else, to get lat and long into a variable in a few line code.

Thanks

Martin

[GaryP]

It is pure fun to dig old boxes and wonder what have I been doing some years back. Connected modules back together (just for fun?), and problems are back. So I googled, and find my old posts, like a time machine to help my older self...

And we are back in business, GPS is not dead!

Cheers,
Kari