sending sms to multiple contacts using SIM900A

How to send the same message to multiple contacts which are stored in an array of phone numbers, using AT commands for SIM900A gsm modem using 8051 microcontroller.
Should I make a loop?
But then how to pass the variable (array elemenst to AT command)?
Thanks in advance

You need to send AT command one by one to all the numbers in array. You can create a simple wrapper function to send sms where in you can pass mobile number and text to send. then call the function from a for loop.

suppose i have this array
char *phone_no[3 ]={"1234567890\" ," 9087654321\" ,"76676667676\"; //array of pointers

for(i=0;i<3;i++)
{
uart_string("AT+CMGF=1\r\n");
delay_ms(2000);
uart_string("AT+CMGS=\phone_no[i]\r\n");
delay_ms(2000);
uart_string("hello world\r\n");
delay_ms(2000);
uart_data(0X1A); //control+Z
delay_ms(2000);
}


will this work

The site editor may have removed the 0 from \0.
Actually it should not be needed, so
char *phone_no[3 ]={"1234567890" ," 9087654321" ,"76676667676"}; //array of pointers
should work.

No ,its not the null character, its just the '\',
have have read on the google "How to send the msg using AT commands and microcntroller" then the results which I got were,

uart_string("AT+CMGS=\"9999999999\"\r\n"); .......In this format we should code ,,hence i have added '\' as the last character n the array of phone numbers..

IS this wrong??

plz guide me with the correct format for sending the message using AT commands and controller.

you are right ..I should not include '\' at the end of the phone number...
I came to know that we have used \" to print " character since we want ,
AT+CMGS="phone number"; " should be printed and hence we have used \".

Quotes can be tricky, but this should work.

char *phone_no[3 ]={"1234567890" ," 9087654321" ,"76676667676"}; //array of pointers

for(i=0;i<3;i++)
{
uart_string("AT+CMGF=1\r\n"); //probably not be needed each time
delay_ms(2000);
uart_string("AT+CMGS=\""); //open quotes
uart_string(phone_no[i]); //insert number
uart_string("\"\r\n"); //close quotes.. return
delay_ms(2000);
uart_string("hello world\r\n");
delay_ms(2000);
uart_data(0X1A); //control+Z
delay_ms(2000);
}

In a similar project I used \r not \r\n
I don't know if it makes a difference.

Thank you....Now I can send the msg to multiple contacts...
But when i use a serial interrupt I can't send the message to any contact...
Is serial interrupt required for sending the message?

i am also using Rfid module here...
Once the rfid card is readed I have to send the message to the particular number..
Plz help...

But when i use a serial interrupt I can't send the message to any contact...
Is serial interrupt required for sending the message?

Deepakvaishu

You don't need to use the serial interrupt to send.
Most simple programs don't.
Your version of "uart_string()" might , but it's unlikely.
What are you using the serial interrupt for ?

i am also using Rfid module here...
Once the rfid card is readed I have to send the message to the particular number..

Deepakvaishu

You will have to give a lot more detail of the problem.

I am using serial interrupt for RFID card reader,whenever a RFID card is readed then we will get its ascii value (serial interrupt)....
Whenever the RFID card is readed then we should send the message to the specific number.

The problem which I am getting is that whenever I do the GSM and RFID(using serial interrupt code ) both separate , then they are working.

But when I combine both codes together for GSM and RFID ,both are not working..
Here using serial interrupt (for both transmiting(AT commands) and receiving (rfid card ascii value));

plz help.