Use Arduino GSM/GPRS SIM900 to send sensor data to my web service

Question

Thank you in advance. I am beginner in arduino.

My Question is how to send dynamic sensor data (Continuous Readings) to the web server. I tried the below code to setup the GSM/GPRS connection to the server.

I successfully sent some static data which is in the below code. But when I want to include some dynamic data that comes from sensor, I am unable to insert the same in code.

Present Code:

gprsSerial.println("AT+HTTPPARA=\"URL\",\"xxxx/new.php?sensor1=100\"")

Required Code:

gprsSerial.println("AT+HTTPPARA=\"URL\",\"xxxx/new.php?sensor1=DYNAMIC VALUE\"")

ARDUINO CODE USED & TESTED

#include <SoftwareSerial.h>
SoftwareSerial gprsSerial(7, 8);

void setup()
{
  gprsSerial.begin(19200);
  Serial.begin(19200);

  Serial.println("Config SIM900...");
  delay(2000);
  Serial.println("Done!...");
  gprsSerial.flush();
  Serial.flush();

  // attach or detach from GPRS service 
  gprsSerial.println("AT+CGATT?");
  delay(100);
  toSerial();


  // bearer settings
  gprsSerial.println("AT+SAPBR=3,1,\"CONTYPE\",\"GPRS\"");
  delay(2000);
  toSerial();

  // bearer settings
  gprsSerial.println("AT+SAPBR=3,1,\"APN\",\"xxxx\"");
  delay(2000);
  toSerial();

  // bearer settings
  gprsSerial.println("AT+SAPBR=1,1");
  delay(2000);
  toSerial();
}


void loop()
{
   // initialize http service
   gprsSerial.println("AT+HTTPINIT");
   delay(2000); 
   toSerial();

   // set http param value
   gprsSerial.println("AT+HTTPPARA=\"URL\",\"http://www.oniee.com/new.php?sensor1=100\"");
   delay(2000);
   toSerial();

   // set http action type 0 = GET, 1 = POST, 2 = HEAD
   gprsSerial.println("AT+HTTPACTION=0");
   delay(6000);
   toSerial();

   // read server response
   gprsSerial.println("AT+HTTPREAD"); 
   delay(1000);
   toSerial();

   gprsSerial.println("");
   gprsSerial.println("AT+HTTPTERM");
   toSerial();
   delay(300);

   gprsSerial.println("");
   delay(10000);
}

void toSerial()
{
  while(gprsSerial.available()!=0)
  {
    Serial.write(gprsSerial.read());
  }
}

Answer 1

It all depends on where your getting your dynamic data but for this example I'm going to use a digital input on a single pin

int readpin = 4;
byte pinValue;

void loop()
{
   // initialize http service
   gprsSerial.println("AT+HTTPINIT");
   delay(2000); 
   toSerial();

   pinValue = digitalread(readpin);

   // set http param value
   gprsSerial.println("AT+HTTPPARA=\"URL\",\"http://www.oniee.com/new.php?sensor1="" + pinValue + ""\"");
   delay(2000);
   toSerial();

   ...

The number of " might be a little off I don't have a setup to test this on right now, but this basic idea is:

Check the pin (or pins) for value
Store the value
Include the value in your string