Fail to retrieve the value from gsm sim 900A by using AT Command to PHP script I am currently trying to establish a connection between my gsm sim900A to one of my test server. The connection seems pretty good so far, though I'm a little bit confused why there are no values retrieved by my php file. Even so, the insert query works although it insert empty value into the database. So my question is how to retrieve it properly? I already change the method in php script to POST, both of it doesn't return any good signs. 

Arduino Code:

void postData()
{
  sim900a.println("AT+HTTPINIT");
  delay(1000);
  printSerialData();

  sim900a.println("AT+HTTPPARA=\"CID\",1");
  delay(1000);
  printSerialData();

  sim900a.println("AT+HTTPPARA=\"URL\",\"test.my/demo/writedata.php\"");
  delay(1000);
  printSerialData();

  sim900a.println("AT+HTTPDATA=12,10000");
  delay(1000);
  printSerialData();

  sim900a.println("strBoton=999");
  delay(1000);
  printSerialData();

  sim900a.println("AT+HTTPACTION=1");
  delay(1000);
  printSerialData();

  sim900a.println("AT+HTTPREAD");
  delay(1000);
  printSerialData();

  sim900a.println("AT+HTTPTERM");
  delay(1000);
  printSerialData();
}


PHP Code:

&lt;?php
$servername = "test.my";
$username = "****";
$password = "****";
$dbname = "test";

$conn = new mysqli($servername, $username, $password, $dbname);

if ($conn-&gt;connect_error) {
    die("Connection failed: " . $conn-&gt;connect_error);
} 

$Boton = $_GET["strBoton"];

$sql = "INSERT INTO test VALUES ('$Boton')";   

if ($conn-&gt;query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "&lt;br&gt;" . $conn-&gt;error;
}
$conn-&gt;close();
?&gt;


Output:

AT+HTTPINIT
OK

AT+HTTPPARA="CID",1
OK

AT+HTTPPARA="URL","test.my/demo/writedata.php"
OK

AT+HTTPDATA=12,10000
DOWNLOAD
OK

AT+HTTPACTION=1
OK

AT+HTTPREAD
OK

AT+HTTPTERM
+CME ERROR: operation not allowed

AT+SAPBR=0,1
OK
I am not sure but, in this tutorial at page 8, it does almost the same code pattern like yours. You might want to check it. Sorry but I don't know PHP, I can't help you with it. 

But I am confused with AT+HTTPACTION, since AT+HTTPACTION=0 is the read and AT+HTTPACTION=1 is the post. Check the tutorial and optimize your commands.

Also check this one. It writes WAIT=6 after AT+HTTPREAD before terminating it.