SIM900 gprs web with arduino

Question

I have a problem with this simple code.

#include <SoftwareSerial.h>

SoftwareSerial SIM900(7, 8); // configure software serial port

void setup() {     
  pinMode(9, OUTPUT);
  digitalWrite(9, HIGH);

  SIM900.begin(19200);
  Serial.begin(19200); 
  Serial.println("power up" );
  delay(15000); 
}

void loop()
{
  Serial.println("SubmitHttpRequest - started" );
  SubmitHttpRequest();
  //callSomeone();
  Serial.println("SubmitHttpRequest - finished" );
  delay(10000);

}

void SubmitHttpRequest()
{
  SIM900.println("AT+CSQ"); // Signal quality check
  delay(100);
  ShowSerialData();

  SIM900.println("AT+CSQ"); // Signal quality check
  delay(100);
  ShowSerialData();

  SIM900.println("AT+CGATT?"); //Attach or Detach from GPRS Support
  delay(100);
  ShowSerialData();

  SIM900.println("AT+SAPBR=3,1,\"CONTYPE\",\"GPRS\"");
  delay(1000);
  ShowSerialData();

  SIM900.println("AT+SAPBR=3,1,\"APN\",\"gprs-service.com\"");
  delay(1000);
  ShowSerialData();

  SIM900.println("AT+SAPBR=1,1");
  delay(1000);
  ShowSerialData();

  SIM900.println("AT+HTTPINIT"); //init the HTTP request
  delay(1000); 
  ShowSerialData();

  SIM900.print("AT+HTTPPARA=\"URL\",\"http://xxxxxx.com/master.php");
  SIM900.println("\"");
  delay(1000);
  ShowSerialData();

  SIM900.println("AT+HTTPACTION=0");//submit the request 
  delay(10000);
  ShowSerialData();

  SIM900.println("AT+HTTPREAD");// read the data from the website you access
  delay(500);
  ShowSerialData();

  SIM900.println("");
  delay(100);

  SIM900.println("AT+HTTPTERM");// read the data from the website you access
  delay(300);
  ShowSerialData();
}

void getContent()
{
  String content = "";
  while(SIM900.available() != 0)
  {
    content = content + String(char(SIM900.read()));
    Serial.write(char(SIM900.read()));
    delay(500);
    Serial.flush();
  }
}

void ShowSerialData()
{
  while(SIM900.available()!=0)
    Serial.write(char (SIM900.read()));
}

Receipt few characters, the output is this:

power up
SubmitHttpRequest - started
AT+CSQ

+CSQ: 25,0

OK
AT+CSQ

+CSQ: 25,0

OK
AT+CGATT?

+CGATT: 1

OK
AT+SAPBR=3,1,"CONTYPE","GPRS"

OK
AT+SAPBR=3,1,"APN","gprs-service.com"

OK
AT+SAPBR=1,1

OK
AT+HTTPINIT

OK
AT+HTTPPARA="URL","http://xxxxxx.com/master.php"

OK
AT+HTTPACTION=0

OK

+HTTPACTION:0,200,66
AT+HTTPREAD

+HTTPREAD:66
Numero de accesos: 77 | Identifica
AT+HTTPTERM

OK
SubmitHttpRequest - finished

==> "Numero de accesos: 77 | Identifica"

But, realy, the output should be:

Numero de accesos: 77 | Identificador: 4l02pnl828o3kctg4strc87ed1

Exactly like: HTTPREAD missing characters with Arduino and SIM900

Any ideas or help?

Thanks!

dmSherazi dmSherazi · Accepted Answer · 2015-11-28T10:01:21

Numero de accesos: 77 | Identifica is 34 charcters. This means that sim900 gives back 66 characters which is the correct length.

Try to increase the delay before ShowSerialData or wait until you have 66 bytes in serial buffer.

SIM900 gprs web with arduino

1 Answers