Mobile Phone Simulator using GSM module

[[wysiwyg_imageupload:3223:]] This Project is submitted by Mr. Himanshu Choudhary from MNIT, Jaipur

This is an interesting application which controls the GSM modem using software designed and developed in C# on .Net framework. There is no need of microcontroller in between. The GSM modem is connected to the PC using a cross connection serial cable. This is a sort of mini simulator for mobile phones. Using this application you can call a number, send SMS etc. It is recommended to read our earlier articles on GSM Modem, interfacing GSM modem and AT commands before for better understanding this project.

Description

GSM module acts as a gateway to connect you to the mobile network. It can take input from the PC using serial port. The module used here has an onboard MAX 232 IC and hence can be connected directly to the computers serial port using a cross connection serial cable. In case the modem is not having on board MAX 232 you need to build a circuit using MAX 232 to connect the GSM module to the PC. The rest of the work is of software. This software has been designed in C#. The software interacts with the serial port using the inbuilt .NET Libraries. It sends AT commands to the GSM modem using serial port corresponding to the function which needs to be performed. Similarly the output of the GSM modem is taken serially and displayed on the software. This is a demo version and can perform four functions:

1. Check_Modem:

It will tell you the status of Modem i.e., whether the modem is ready to use or not. When you press the “Check Modem” button, it will display “OK” in the Display box box in case modem is properly connected and is ready else nothing will be returned. Check the modem connection, modem, and serial cable in case it is not working.

This functionality is achieved by using the command “AT”. Whenever modem receives AT followed by <enter> it responds to command and send ‘OK’ back to host if it is ready.

Algorithm: When we press “Check modem” button

a. Serial port is opened and GSM modem gets connected with baud rate of 9600.

b. Command ‘AT<enter> ‘ is send serially to modem.

c. If modem is working properly it retunes ‘OK’ that is displayed in text box.

2. IMEI:

Each GSM modem has a unique IMEI number which can be checked using the “AT+GSN<enter>” command.

Algorithm

a. Serial port is opened and GSM modem gets connected with baud rate of 9600.

b. Command “AT+GSN<enter>” is send serially to modem.

c. Modem respond to this command by returning its IMEI number back to host which is displayed in display box.

3. Dial

This function is used to make a call to a particular number. This is done by sending the command “ATD<number><enter>” to the modem. Modem responds to this command by dialing the number.

Let’s assume you want to make a call to a number “9999999999”. The number should be a 10 digit number. In case you want to dial to landline number type the std code followed by the number.

Algorithm

a. Serial port is opened and GSM modem gets connected with baud rate of 9600.

b. Type the number you want to dial in the text box given in the right side.

c. Command “AT9345671234<enter>” is send serially to modem.

d. Modem responds to this command by dialing the number.

4. Send_Message

This function is used to send a message to a mobile numbers. This is done through set of AT commands:

AT+CMFG=1

AT+CMGS=<number>

<Message body

to be send>

Control +Z (ASCII): To terminate the message body.