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8051 to control GSM modem

Tue, 13 May 2008 15:39:33 -0700

Hi guys, I'm a student doing a final year project. My project needs a 8051 microcontroller to program and run a GSM modem to send, read and receive SMS's but the thing is..I'm a total newbie to the 8051.

I need help in the programming part and we're probably going to use Keil C to program the 8051. The modem we're using is a Wavecom fastrack 10 supreme.

Another question: Is there any hardware that can receive SMS and power up devices? (eg. LEDs, buzzer..etc) Prefabaly a small and inexpensive one.

I hope to hear from you all soon as its kinda urgent. Thanks in advance.

Re: 8051 to control GSM modem

Tue, 13 May 2008 19:46:16 -0700

search the site with your querry...

u will find ur answers for sure..

use the search tab at the top left1

Re: 8051 to control GSM modem

Wed, 14 May 2008 00:48:01 -0700

Thanks for your advice but I've searched the forums and found nothing much on using 8051 to control a wavecom GSM modem.

Re: 8051 to control GSM modem

Wed, 14 May 2008 05:08:19 -0700

u said u r using fasttrack supreme...

u shud have got urself a wavecom q24plus on the first hand.. there u wud have got an inbuilt ARM-7tdmi based controllers with IP support as wellas a few GPIOs to control.. as u said u needed, look if u can still get one.. nevertheless, wavecom supreme is pretty easy to interface..

get urself a working 8051 board and have it interfaced with PC (serially)..
now see if u can communicate ur 51board and PC properly..(write a small serial code).

u will have to try and write code @115200 baudrate.
else u will have to bring the baudrate of the modem down to say 9600.. will tell u how.. but before that,try what has been said above and let us know!

Re: 8051 to control GSM modem

Wed, 14 May 2008 09:22:43 -0700

Thanks. I'll try that. If I still have any problems, I'll post again.

Re: 8051 to control GSM modem

Tue, 20 May 2008 01:04:03 -0700

Is there a tutorial or website that teaches you how to send AT commands with C?

Or if any of you here can teach me some basics?

Thanks.

Re: 8051 to control GSM modem

Tue, 20 May 2008 18:58:11 -0700

all you need to do is.. configure your uart.
create a function to send string.

then send command like this

CODE:

send("AT\r"); //send is your function to send string
//at command sent.
 

Re: 8051 to control GSM modem

Tue, 20 May 2008 22:19:41 -0700

Thanks dude. That was what I was looking for.

Re: 8051 to control GSM modem

Wed, 21 May 2008 22:49:49 -0700

do not forget to disable echo, coz that can create problem for you.

ATE0 - disable echo

Re: 8051 to control GSM modem

Fri, 30 May 2008 00:46:04 -0700

for this you need to do some string manipulation functions..
see the response you get from AT Commands will always be in the above format.
after the above string you will have the sms data.. and then OK
something like this.

+CMGR: "REC UNREAD", "0146290800",
"98/10/01,18:22:11+00", ABCdefGHI
OK

you can create function which can break this string into parts so that you can get extract information from it.
so do this..
look for index of first "," (comma) and then after that keep reading the string from starting quote to ending quote. you have your number in between that.

c example:

CODE:

while(*response != ',')
        response++;
//after you come out of the above loop you reached the starting of number
response++; //bypass the space
response++; //bypass quote
while(*response != '"'){
        *number = *response;
        number++;
        response++;
}
 

now string number will have your number

Re: 8051 to control GSM modem

Thu, 29 May 2008 21:25:04 -0700

Ok, I'm able to send AT commands to the modem but how do I read values from it?

+CMGR : "REC UNREAD", "+6512345678", "08/05/27"

How do I read the number, +6512345678, and send a reply or something similar in C language?

Thanks.

Re: 8051 to control GSM modem

Fri, 30 May 2008 13:28:28 -0700

Hey, thanks.
I'll try that out.

Re: 8051 to control GSM modem

Wed, 04 Jun 2008 17:21:04 -0700

Hi,
You can register yourself in Wavecom Website. and can get downloaded AT Command Interface guide. Also try to get some basic knowledge of GSM modem and phone behavior, so it will be more helpful for you to interface with MICON.

Re: 8051 to control GSM modem

Tue, 24 Jun 2008 19:07:46 -0700

Alright, I can get my 8051 to communicate with my serial port and now I have another problem. How do I send sms with the GSM in C? I know how to send strings to read and delete SMS but I have a problem with sending SMS.

Sending SMS for my GSM is:
AT+CMGS = +123456789 [enter button]
[control+Z]

The problem is I don't know how to input the enter button and the control+Z into the string. Thanks.

Re: 8051 to control GSM modem

Tue, 24 Jun 2008 22:46:32 -0700

Judgement wrote ...

\r\n should work here, if don't then you can try with the hex code of Line feed/Carriage return. I had not tried it yet so don't know if it works!

Re: 8051 to control GSM modem

Wed, 25 Jun 2008 00:04:30 -0700

say2paul wrote ...

Judgement wrote ...

\r\n should work here, if don't then you can try with the hex code of Line feed/Carriage return. I had not tried it yet so don't know if it works!

Hmm..I've thought of using \r\n as well but I haven't tried it out yet. I don't think it works that way...

Re: 8051 to control GSM modem

Wed, 25 Jun 2008 01:21:08 -0700

Judgement wrote ...

say2paul wrote ...

Judgement wrote ...

\r\n should work here, if don't then you can try with the hex code of Line feed/Carriage return. I had not tried it yet so don't know if it works!

Hmm..I've thought of using \r\n as well but I haven't tried it out yet. I don't think it works that way...

You are lucky you reached at the point where you are sending AT commands from 8051 to mobile phone.

I am still finding how to connect my mobile phone with microcontroller

Re: 8051 to control GSM modem

Wed, 25 Jun 2008 04:27:33 -0700

say2paul wrote ...

You are lucky you reached at the point where you are sending AT commands from 8051 to mobile phone.

I am still finding how to connect my mobile phone with microcontroller

Well, I'm using a GSM modem instead of a mobile phone. I think its easier to configure the 8051 to communicate with the GSM as compared to a mobile phone. Good luck on your project.

Re: 8051 to control GSM modem

Wed, 25 Jun 2008 18:13:34 -0700

I have 1 more question. I'll post it up with my old question.

Alright, I can get my 8051 to communicate with my serial port and now I have another problem. How do I send sms with the GSM in C? I know how to send strings to read and delete SMS but I have a problem with sending SMS.

Sending SMS for my GSM is:
AT+CMGS = +123456789 [enter button]
[control+Z]

The problem is I don't know how to input the enter button and the control+Z into the string in C language. Thanks.

Also, I want to do something like a timed SMS. The user send an SMS eg. 1 Hour.
Then, the 8051 programs the GSM modem to send an SMS 1 hour later. How can I do something like that in C language? Thanks.

Re: 8051 to control GSM modem

Thu, 26 Jun 2008 00:27:21 -0700

Ok, I've solved the sending SMS problem. However, I still have some problems with the timed SMS thing.
Hope to see some replies soon. Thanks.

Re: 8051 to control GSM modem

Thu, 26 Jun 2008 07:29:16 -0700

timers? or any hardware clock for better accuracy...

Re: 8051 to control GSM modem

Thu, 26 Jun 2008 18:20:56 -0700

Ajay wrote ...

timers? or any hardware clock for better accuracy...

Hmm..trying not to add any additional hardware.
Its more like a delayed SMS. The user sends the time by SMS for the SMS to be sent by the GSM modem to be delayed. eg.1 hour
And the modem sends an SMS to the sender after 1 hour has passed.

Re: 8051 to control GSM modem

Sun, 29 Jun 2008 06:25:45 -0700

Also, how can I program it so that the GSM modem only continues with the program when the correct SMS text is sent?

eg. 1 hour

When the GSM modem receives something else, it will ignore it. Thanks. I need it kind of urgently.

Re: 8051 to control GSM modem

Tue, 12 Aug 2008 23:14:27 -0700

You can use this +6512345678 directly as ASCII charachter with AT+CMGS for exmple

AT+CMGS="+6512345678"\r