GPS Format not readable

Projects Programming
1

Hello,
I am using SIM808 with GPS+GSM module.

My result is not providing the result as expected. I want when AT+CGPSSTATUS? value is "Location 3D Fix", then AT+CGPSOUT=2 will fire. I have put this logic in loop. After that the GPS format is not readable.
Whereas when I am performing this action manually from command terminal software it is working fine.
Below is my sketch:

#include <SoftwareSerial.h>
#define RXPIN 5
#define TXPIN 4

SoftwareSerial gpsSerial(TXPIN , RXPIN);  //4 is for TX and 3 is for RX

void setup() {
  Serial.begin(4800);
  gpsSerial.begin(4800); // connect gps sensor
  gpsSerial.println("AT");
  delay(1000);
  printSerialData();
  gpsSerial.println("AT+CGPSPWR=1");
  delay(2000);
  printSerialData();
  gpsSerial.println("AT+CGPSRST=0");
  delay(3000);
  printSerialData();
  gpsSerial.println("AT+CIPSHUT");
  delay(3000);
  printSerialData();
  gpsSerial.println("AT+CIPMUX=0");
  delay(2000);
  printSerialData();
  gpsSerial.println("AT+CGATT=1");
  delay(1000);
  printSerialData();
  gpsSerial.println("AT+CSTT=\"voda.com\",\"\",\"\"");
  delay(1000);
  printSerialData();
  gpsSerial.println("AT+CIICR");
  delay(6000);
  printSerialData();
  gpsSerial.println("AT+CIFSR");
  delay(6000);
  printSerialData(); 
  }
  void loop()
  {
    char c = gpsSerial.println("AT+CGPSOUT=2");
    String gpssatatus = "Location 3D Fix";
    
    //gpsSerial.println(c);
    delay(3000);
    while (gpssatatus != 0)
    {
      gpsSerial.println("AT+CGPSSTATUS?");
      printSerialData();
    }
    gpsSerial.println(c);
    printSerialData();
  }

The below is the output I a getting:

+CGPSSTATUAT+CIPSHUT

+CGPSSTATUS: Location 3D Fix

OK
$GPGGA,140214.AT+CIPMUX=0

+CGPSSTATUS: Location 3D Fix

OK
$GPGGA,140217AT+CGATT=1

+CGPSSTATUS: Location 3D Fix

OK
$GPGGA,140219.AT+CSTT="voda.com","",""

+CGPSSTATUS: Location 3D Fix
AT+CIICR

+CGPSSTATUS: Location 3D Fix

OK
$GPGGA,140222.00AT+CIFSR

+CGPSSTATUS: Location 3D Fix

OK
$GPGGA,140228.00AT+CGPSOUT=2

+CGPSSTATUS: Location 3D Fix

OK
$GPGGA,14023⸮⸮⸮⸮⸮ɚ⸮r⸮$⸮r⸮⸮⸮⸮⸮Db⸮d$ibrb⸮Tt⸮⸮⸮⸮S⸮ը⸮*PU⸮(⸮⸮T*PUCPTUPU⸮CPT*PUCCTUP⸮*H⸮]Z⸮⸮ Fi=-5jZ5⸮⸮Uե⸮5⸮⸮⸮T⸮⸮⸮⸮⸮BT*UU*'Ӭ]Z⸮⸮⸮ix
⸮5Q⸮⸮EQU⸮
Z5E⸮j(ji⸮UU⸮⸮ii⸮*(⸮⸮CPTUPU⸮⸮

Please advice

Thanks-
Pokhraj

2 
    char c = gpsSerial.println("AT+CGPSOUT=2");

What do you expect 'c' to contain?!? I think what you get back is the number of characters sent. I think in this case it will be 12.

    gpsSerial.println(c);

I don't think this is going to do whatever you intended it to do!

I think for that first part you maybe meant:

    const char *c = "AT+CGPSOUT=2";
  gpsSerial.println(c);
3

Hello
I have written one new sketch from the scratch. It is working as expected. $GPGGA data is coming at serial monitor as expected.

The problem is when I send the data by using AT+CIPSEND, the result is coming "SEND OK". But at the Server window[I am using TC/IP server. GSM is client, and my Laptop is server] it is showing AT+CIPSEND=1, not the string "$GPGGA". Am I doing any mistakes?

Here is the below sketch.

#include <SoftwareSerial.h>
#include<stdio.h>
#include<string.h>
#define DEBUG true
#define RXPIN 5
#define TXPIN 4

SoftwareSerial mySerial(TXPIN , RXPIN);  //4 is for TX and 3 is for RX

void setup() {
  Serial.begin(4800);
  mySerial.begin(4800); // connect gps sensor
  sendData("AT+CIPSHUT\r\n",1000,DEBUG);
sendData("AT+CIPMUX=0\r\n",1000,DEBUG);
sendData("AT+CGATT=1\r\n",1000,DEBUG);
sendData("AT+CSTT=\"voda.com\",\"\",\"\"\r\n",1000,DEBUG);
sendData("AT+CIICR\r\n",2000,DEBUG);
sendData("AT+CIFSR\r\n",1000,DEBUG);
sendData("AT+CIPSTART=\"TCP\",\"xxx.xxx.xxx.3\",\"4001\"\r\n",1000,DEBUG);

  }
  void loop()
  {
getgps();
   while(1)
   {
        //sendData( "AT+CGPSOUT=2",1000,DEBUG);
        String gpsoutput="AT+CGPSOUT=2";
        String cipSend ="AT+CIPSEND=";
        cipSend +=String(gpsoutput.length());
        cipSend +="\r\n";
        sendData(cipSend,500,DEBUG);
     delay(2000);   
        //delay(3000);
   }
  }




void getgps(void)
{
   sendData( "AT+CGNSPWR=1",1000,DEBUG); 
   sendData( "AT+CGNSSEQ=GGA",1000,DEBUG); 
}

String sendData(String command, const int timeout, boolean debug)
{
    String response = "";    
    mySerial.println(command); 
    long int time = millis();   
    while( (time+timeout) > millis())
    {
      while(mySerial.available())
      {       
        char c = mySerial.read(); 
        response+=c;
      }  
    }    
    if(debug)
    {
      Serial.print(response);
    }    
    return response;
}

Please advice.

4

It might help to log both the Command (as sent) and the response:

#include <SoftwareSerial.h>

const boolean DEBUG = true;
#define RXPIN 5
#define TXPIN 4

SoftwareSerial mySerial(TXPIN , RXPIN);  //4 is for TX and 3 is for RX

void setup() {
  Serial.begin(4800);
  mySerial.begin(4800); // connect gps sensor
  
  sendData("AT+CIPSHUT\r\n", 1000, DEBUG);
  sendData("AT+CIPMUX=0\r\n", 1000, DEBUG);
  sendData("AT+CGATT=1\r\n", 1000, DEBUG);
  sendData("AT+CSTT=\"voda.com\",\"\",\"\"\r\n", 1000, DEBUG);
  sendData("AT+CIICR\r\n", 2000, DEBUG);
  sendData("AT+CIFSR\r\n", 1000, DEBUG);
  sendData("AT+CIPSTART=\"TCP\",\"xxx.xxx.xxx.3\",\"4001\"\r\n", 1000, DEBUG);

  // formerly in void getgps(void)
  sendData( "AT+CGNSPWR=1", 1000, DEBUG);
  sendData( "AT+CGNSSEQ=GGA", 1000, DEBUG);
}

void loop()
{
  //sendData( "AT+CGPSOUT=2",1000,DEBUG);
  String gpsoutput = "AT+CGPSOUT=2";
  String cipSend = "AT+CIPSEND=";
  cipSend += String(gpsoutput.length());
  cipSend += "\r\n";
  sendData(cipSend, 500, DEBUG);
  delay(2000);
}

String sendData(String command, const int timeout, boolean debug)
{
  String response = "";
  if (debug) {
    Serial.print(F("Command: \""));
    Serial.print(command);
    Serial.println("\"");
  }
  mySerial.println(command);

  long int time = millis();
  while (millis() - time < timeout)
  {
    while (mySerial.available())
    {
      char c = mySerial.read();
      response += c;
    }
  }
  if (debug)
  {
    Serial.print(F("Response: \""));
    Serial.print(response);
    Serial.println("\"");
  }
  return response;
}
5 
#define RXPIN 5
#define TXPIN 4

SoftwareSerial gpsSerial(TXPIN , RXPIN);  //4 is for TX and 3 is for RX

When the comments don't match the code, the programmer looks foolish. That's not what you want, is it?

6

I ran the sketch. Here the output I am getting at serial monitor:

Response: "
SEND OK
$GPGGA,191304.000,2227.7441,N,08822.3991,E,1,9,1.00,AT+CIPSEND=12


> $GPGGA,191306.000,2227.7441,N,08822.3991,E,1,9,1.00,16.2,M,-55.7,M,,*46
"
Command: "AT+CIPSEND=12
"
Response: "$GPGGA,191307.000,2227.7441,N,08822.3991,E,1,9,1.00,16.2,M,-55.AT+CIPSEND=12

$GPGGA,191309.000,2227.7441,N,08822.3990,E,1,9,1.00,16.2,M,-55.7,M,,*48
"
Command: "AT+CIPSEND=12
"
Response: "
SEND OK
$GPGGA,191310.000,2227.7441,N,08822.3990,E,1,9,1.00,AT+CIPSEND=12


> $GPGGA,191312.000,2227.7441,N,08822.3990,E,1,9,1.00,16.2,M,-55.7,M,,*42
"
Command: "AT+CIPSEND=12
"
Response: "$GPGGA,191313.000,2227.7441,N,08822.3990,E,1,9,1.00,16.2,M,-55.AT+CIPSEND=12

$GPGGA,191315.000,2227.7441,N,08822.3990,E,1,9,1.00,16.2,M,-55.7,M,,*45
"

But at the server program I am getting as below:

1AT+CIPSEND=1AT+CIPSEND=1AT+CIPSEND=1AT+CIPSEND=1AT+CIPSEND=1AT+CIPSEND=1

But I am not able to see any GPGGA value at Server program

Please advice

Thanks-
Pokhraj

7

You said that it works if you issue the commands manually. Do all the commands you send manually get the same responses as they do when the sketch sends them?

8

Do all the commands you send manually get the same responses as they do when the sketch sends them?

Yes... All the commands gives the same responses except AT+CIPSEND.

Manually, I am performing as below:

AT+CIPSEND <Press Enter>
> Sign is coming at command prompt
>Hello test
Press [ctrl+z]
SEND OK

I am able to find the above test Hello test at the server software.

Thanks-
Pokhraj

9

In your sketch you send "AT+CIPSEND=12" which is different from the "AT+CIPSEND" you do manually. What does the "=12" mean?

10

That is what I am not sure about. Is it datalength or bytes?

Thanks-
Pokhraj

11

How do I get the UART data to a string variable?
For example if I want to capture the UART data such as $GPGGA value to a string variable how do I do that?

Below is my sketch:

#include <SoftwareSerial.h>
#include<stdio.h>
#include<string.h>
#define DEBUG true
#define RXPIN 5
#define TXPIN 4

SoftwareSerial mySerial(TXPIN , RXPIN);
char test = mySerial.print();