Hi,

  You'll have to read the mensangem as String and then process this string to define what to do then. Take a look at http://www.seeedstudio.com/wiki/GPRS_Shield_V2.0. there you will find how to do this...here it is some example:

Fun with AT Commands

Step 0: Basic tutorial

AT+SGPIO=OPERATION, GPIO#, FUNCTION, LEVEL

OPERATION

0 = Set GPIO to output or keypad

1 = Read GPIO level (Funtion MUST be set to input ( 0 )

GPIO# SET to the GPIO pin number for the command 1=12

FUNCTION

0 = Set GPIO to INPUT

1 = Set GPIO to OUTPUT

2 = Set GPIO to KEYPAD

LEVEL

0 = Set GPIO to LOW 1 = Set GPIO to HIGH

Example: To set level of GPIO pin 3 HIGH (on);

AT+SGPIO=0,3,1,1

Delete all SMS messages in memory;

YourSerialName.println("AT+CMGD=1,4\r");

Read a SMS in index # 1;

YourSerialName.println("AT+CMGR=2\r");

Read list of SMS messages in memory;

YourSerialName.println("AT+CMGL=\""ALL\"');

Send a SMS message with text in a variable called newMsg;

YourSerialName.print("AT+CMGF=1\r");

delay(500);

YourSerialName.println("AT+CMGS=\"+17065551212\"");

delay(1500);

YourSerialName.println(newMsg);

or

YourSerialName.println("Hello World");

delay(100);

GPRS.println((char)26); // End AT command with a ^Z, ASCII code 26

Hope this is helpful to others who are enjoying this shield.