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Read SMS From GSM Module : SMS Based Control System By 8051

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Newbie level 4
Mar 12, 2010
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Hello, i am designing SMS Based Device Control System Using AT89S52, i have some trouble reagrding SMS reading...
Through Mobile SMS i need to control assume 4 devices in circuit so i mean i will message in short like this...

D1 - Device 1 ON
D2 - Device 2 ON
D3 - Device 3 ON
D4 - Device 4 ON

to gsm module this sms is sent, but now the trouble comes, that how to read this sms and give the signal to 8051 controller to operate according device...
in simple way i need to read sms that i sent like D1 sms for controlling Device 1, how to read this sms that will help me to control the devices... please help me if someone give me full sms reading code tutorial then surely appreciated...

go through the following file u will get the idea.............


  • gsm.txt
    4.5 KB · Views: 391
bit confused in functions written in the program.. so it would be better to run this program with little change with my program (only LCD programming change) then see what happens... anyway jjeevan007 thanks...
if u want u can delete the displaying part........

main thing is receiving the data from gsm its correct which works fine..........

if u have any doubts u are welcome
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thanx for the code. what are u comparing in the code with two mobile nos?

controlling of the devices is using only a predefined number only......

thats why we are comparing the two mobile numbers

what is the keyword that has to be messaged to gsm modem to switch on a device?


Thanks jjeevan007. actually i am building a security system which will send sms if the system gets interrupted. For activating the system i want to send a sms to the system. i am able to send sms from gsm modem to mobile but i am unable to receive the sms in gsm modem using 89s52. Please help me.


please help me.....

- - - Updated - - -

please help me.....

why dont u activate the security system using the push button........

go through the following file u will get the idea.............
I want to jnow where's the attached file I m also workinmin tne project and having dificulties with ciding

Is that the full program or I need to change something in that??

it is the full program, it displays the message on to the lcd
Thanks sir...
I think it will control the devices too that are connected to the uc and as well as display the message on the lcd??
Am I right??

i do not get the functions data_res() and data_send what do these functions do
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data_send function is used to send AT command to GSM module.
data_res function is used to read AT command response from GSM module but i think data_res function is not write properly to handle reply from GSM module it just flush out data from GSM module.

i am designing the same project on pic18f452 i have made changing to the above code can you please tell me if my code is correct


  • gsm_pic18.txt
    2.7 KB · Views: 155


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I have doubt about where the received message is stored? Is it in the the SBUF of the 8051 microcontroller?

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