Sim800L not working with SD Card Module

Other Hardware Storage
1

I was working with Sim800l and the SD card module where there are a number of contact details whose names with phone numbers are stored on the SD card

[example: 9860xxxxxx-Kapalik].

And when Sim800L gets a call, it first compares a number from the SD card and if the contact details are from that list, it sends the callername to the server. Everything works just fine when I run these functions separately, but when I use both functions at the same time on a loop(), the function name compareCaller() does not get executed. Please help.

Codes:

void loop() {
  char phone[32] = "98xxxxxxxx";
  compareCaller(phone);
  delay(5000);
  sendDataToServer();
  delay(20000);
}

void compareCaller(char number[32]) {
  myFile = SD.open("numbers.txt");
  if (myFile) {
    Serial.println("numbers.txt:");
    while (myFile.available()) {
      buffer = myFile.readStringUntil('\n');
      char charBuf[50];
      buffer.toCharArray(charBuf, 50);
      char *callerNumber = strtok(charBuf, "-");
      char *Name = strtok(NULL, '\n');
      if (strcmp(callerNumber, number) == 0) {
        callerName = Name;
        Serial.println(callerName);
        break;
      }
      delay(10);
    }
    Serial.println(callerName);
    myFile.close();
  }
  else {
    Serial.println("error opening test.txt");
  }
}

int sendDataToServer()
{
  String latitude, longitude;
  latitude = callerName;
  longitude = random(2, 20);
  Serial.print("Latitude= ");
  Serial.print(latitude);
  Serial.print(" Longitude= ");
  Serial.println(longitude);
  String url, temp;
  url = "http://debilitative-tacks.000webhostapp.com/gpsdata.php?lat=";
  url += latitude;
  url += "&lng=";
  url += longitude;
  //https://debilitative-tacks.000webhos
  //url = "http://ahmadssd.000webhostapp.com/gpsdata.php?lat=222&lng=222";

  Serial.println(url);
  delay(300);

  sendATcommand("AT+CFUN=1", "OK", 2000);
  sendATcommand("AT+CGATT=1", "OK", 2000);
  sendATcommand("AT+SAPBR=3,1,\"Contype\",\"GPRS\"", "OK", 2000);
  sendATcommand("AT+SAPBR=3,1,\"APN\",\"web\"", "OK", 2000);
  sendATcommand("AT+SAPBR=1,1", "OK", 2000);
  sendATcommand("AT+HTTPINIT", "OK", 2000);
  sendATcommand("AT+HTTPPARA=\"CID\",1", "OK", 1000);
  fona.print("AT+HTTPPARA=\"URL\",\"");
  fona.print(url);
  sendATcommand("\"", "OK", 1000);
  sendATcommand("AT+HTTPACTION=0", "0,200", 1000);
  sendATcommand("AT+HTTPTERM", "OK", 1000);
  sendATcommand("AT+CIPSHUT", "SHUT OK", 1000);
}

int8_t sendATcommand(char* ATcommand, char* expected_answer, unsigned int timeout) {
  uint8_t x = 0,  answer = 0;
  char response[100];
  unsigned long previous;
  memset(response, '\0', 100);
  delay(100);
  while ( fona.available() > 0) fona.read();
  if (ATcommand[0] != '\0') {
    fona.println(ATcommand);
  }
  x = 0;
  previous = millis();
  do {
    if (fona.available() != 0) {
      response[x] = fona.read();
      x++;
      if (strstr(response, expected_answer) != NULL) {
        answer = 1;
      }
    }
  } while ((answer == 0) && ((millis() - previous) < timeout));
  Serial.println(response);
  return answer;
}

sketch_aug09d.ino (3.8 KB)

2

Many cheap SD Card modules don't work with other SPI modules. They use a level shifter that is always driving the MISO line, even when their SS line is HIGH. Getting a better SD Card module might fix the problem. The one from Adafruit is known to work: