No GPS data coming from Maduino Zero 4G LTE with GPS Module

Solved
1

Details :
• Maduino Zero 4G LTE with GPS Module
• Android 9
• Blynk server = SGP1
• Blynk 2.0

I have similar problem to this post below. But, in my case I have set the data stream to Location type pin V9 and I am still not getting any GPS data from my board. Using AT commands I confirmed that the GPS and GSM works.
https://community.blynk.cc/t/need-help-with-blynk-2-0-and-sim7600e-device-offline/64625

#define DEBUG true
#define MODE_1A

#define DTR_PIN 9
#define RI_PIN 8

#define LTE_PWRKEY_PIN 5
#define LTE_RESET_PIN 6
#define LTE_FLIGHT_PIN 7

String token = "fc6__T-vO15pOh83HDs3gZ6MphVXw0r9";
String from_usb = "";
String loc = "";
String longitude = "";
String lattitude = ""; 

//FUNCTION TO PASS AT COMMAND

String sendData(String command, const int timeout, boolean debug)
{
  String response = "";
  Serial1.println(command);
  
  long int time = millis();
  while ( (time + timeout) > millis())
  {
    while (Serial1.available())
    {
      char c = Serial1.read();
      response += c;
    }
  }
  if (debug)
  {
    SerialUSB.print(response);
  }
  return response;
}

//FUNCTION TO CHECK SIGNAL STRENGTH

int check_signal(void)
{
  while(1)
  {
    String sig = sendData("AT+CSQ",3000,DEBUG);
    int i=0;
    String strength;
    while(sig[i]!=':')i++;

    String loc_2 = sig.substring(i+2);

    i=0;
    while(loc_2[i]!=',')i++;

    strength = loc_2.substring(0,i);

    int strength_1 = strength.toInt();
    SerialUSB.println(strength_1);

    return strength_1;
  }
}

//FUNCTION TO GET LATITUDE AND LONGITUDE STRING

void gpsLocation(String local)
{
//  char* loc_2 = local;
//  int p=0;
  
  while(1)
  {
    int i=0;
    while(local[i]!=':')i++;

    String loc_2 = local.substring(i+2);

    i=0;
    while(loc_2[i]!=',')i++;

    lattitude = loc_2.substring(0,i);
    SerialUSB.println(lattitude);

    int j = i+3;
    int k = j;

    while(loc_2[k]!=',')k++;

    longitude = loc_2.substring(j,k);
    SerialUSB.println(longitude); 

    return;
    
  }
}

//CONVERSION OF GIVEN LATTITUDE FORMAT FROM NMEA TO PARSER

String conversion(String local)
{
  if(local[0]=='0'){
      String str_end = local.substring(3);

      String str_init = local.substring(1,3);

      int val = str_init.toInt();
 
      double deci_val = str_end.toDouble() ;

      double new_value = val+(deci_val / 60);
      SerialUSB.println(new_value);

      String final_val = String(new_value,5);

      return final_val;
   }
  else if(local[0]!='0')
  {
      String str_end = local.substring(2);

      String str_init = local.substring(0,2);

      int val = str_init.toInt();
 
      double deci_val = str_end.toDouble() ;

      double new_value = val+(deci_val / 60);
      SerialUSB.println(new_value);

      String final_val = String(new_value,5);

      return final_val;
  }
}

//FUNCTION TO PASS LOCATION IN BLYNK API

void map_loc(String lat1,String lon1)
{
    String lat = conversion(lat1);
    String lon = conversion(lon1);

    SerialUSB.print("lattitude = ");SerialUSB.println(lat);
    SerialUSB.print("longitude = ");SerialUSB.println(lon);

    String http_str = "AT+HTTPPARA=\"URL\",\"https://sgp1.blynk.cloud/external/api/batch/update?token=" + token + "&V9=" + lon + "&V9=" + lat + "\"\r\n";
    SerialUSB.println(http_str);
    sendData("AT+HTTPINIT\r\n", 3000, DEBUG);
    sendData(http_str, 3000, DEBUG);
    sendData("AT+HTTPACTION=0\r\n", 3000, DEBUG);
    sendData("AT+HTTPTERM\r\n", 3000, DEBUG);
}

void setup(){
  SerialUSB.begin(115200);
  //while (!SerialUSB)
//  {
    ; // wait for Arduino serial Monitor port to connect
//  }

  delay(100);

  Serial1.begin(115200);

  //INITIALIZING GSM MODULE

  pinMode(LTE_RESET_PIN, OUTPUT);
  digitalWrite(LTE_RESET_PIN, LOW);

  pinMode(LTE_PWRKEY_PIN, OUTPUT);
  digitalWrite(LTE_RESET_PIN, LOW);
  delay(100);
  digitalWrite(LTE_PWRKEY_PIN, HIGH);
  delay(2000);
  digitalWrite(LTE_PWRKEY_PIN, LOW);

  pinMode(LTE_FLIGHT_PIN, OUTPUT);
  digitalWrite(LTE_FLIGHT_PIN, LOW); //Normal Mode
  // digitalWrite(LTE_FLIGHT_PIN, HIGH);//Flight Mode

  SerialUSB.println("Maduino Zero 4G Test Start!");

  

  SerialUSB.println(sendData("AT+CGMM\r\n", 3000, DEBUG));
  sendData("AT+CPIN?\r\n",3000,DEBUG);
  
  sendData("AT+COPS?\r\n",3000,DEBUG);

  sendData("AT+CNUM\r\n",3000,DEBUG);

  //INITIALIZING GPS MODULE
  
  sendData("AT+CGPS=1",3000,DEBUG);
  delay(60000);

  
}

void loop(){

    //CHECKING SIGNAL STRENGTH
    
    if(check_signal()>=10)
    {
      loc = sendData("AT+CGPSINFO\r\n",3000,DEBUG);
      gpsLocation(loc);
      if(lattitude!=""&& longitude!="")
      {
        map_loc(lattitude,longitude);
      }
      delay(5000);  
    }    
}
2

After trying again. I can see there is GPS location data going to Blynk datastream. But checking the map, the GPS data is way off. I am based in the Philippines and the GPS location is in Africa.

lattitude = 14.40851
longitude = 12.96227

This is after I enter command AT+GPSINFO
CGPSINFO: 1424.510265,N,12057.735365,E,220123,130410.0,20.8,0.0,68.5

Anyone can tell me why that happens?

3

You’re using the batch update API instead of the update datastream API

Pete.

1 Like
4

Thanks. I have switched to using update datastream API.

With regards to the way-off GPS location, I think I have a parsing issue. I will review the code and fix it.

Regards,
Markel

5

If your map is showing the location as being here:

image
image1319×643 152 KB

then it’s because its using the coordinates of:

latitude = 14.40851
longitude = 0

and that’s probably because your uploaded coordinates aren’t being treated as coordinates by Blynk - most likely because you’re using the wrong API method.

Pete.

6

Hi Pete,

I found the issue in the code, conversion of NMEA to D.d decimal degrees. I fixed it and I got the correct conversion.

+CGPSINFO: 1424.515048,N,12057.739827,E,230123,074644.0,15.6,0.0,151.4

Converted correctly is:
lattitude = 14.40858
longitude = 120.96233

This post is resolved thanks for your time.

Regards,
Markel

1 Like