Discussion in "Embedded GSM Development" started by    vinay1277    Dec 20, 2007.
Thu Dec 20 2007, 07:15 pm
I have worked on SMS based control panel and in the field it is working fulfilling its objective . But here problem is lack of online two way data transfer between remote microcontroller and computer terminal.As almost all GSM modem have GPRS feature i want to use it . I lack in expertise on web part . I need to develope web part which will act as media between microntroller based field panel having GPRS modem and my computer. Anybody who has worked in this line is requested to help in achieving objectives. I have SIM300 modem which is cheap as well as robust also. Please help.
Thu Dec 20 2007, 11:35 pm
well u r using SIMCOM modem... gr8.....
well there are set of commands u need to fire from uart of a UC.....
what do u intend to do ??
ip packets? SMTP? or FTP??
Fri Dec 21 2007, 09:02 am
Please see attachment . I intend to use AT commands specific for GPRS communication. These commands will be released from serial port of 8051 MCU .
Now as regards question
what do u intend to do ??
ip packets? SMTP? or FTP??
I wish to say i do not have any specific choice . Any media / protocol resources which is readily available for to proceed further shall be a choice .
Please refer to attachment
Here you will find that using AT command we can hoop up to airtel and even get dynamic IP address.Now suppose i want to transmit 123456789 to remote host then i do need to have its IP addresse. We can connect using at command AT+CIPSTART......
Missing factor in my case is Fact that i do not have any IP addresse to experiment with .
Secondly even if i have IP addresse i need to have a WEB interface which will interpret this string 123... and store it in its database so that this string/data 123........ can be read from a comuter hooked up to internet .
This is tentative roadmap for data transfer from PANEL side to comuter.
On the other hand suppose i want to change field parameters in the panel then we need to store changed parameters in the database residing in web server. Field Panel will periodocally scan this field in the database if any change is detected it will change accordingly .
Hardware/software part from Panel side is not a problem however WEB part is putting break in development as i have not worked in this particular line. But i am determined to do it .
I hope requiremnt of project is bit clear .
Looking forward for comments and help.

Fri Dec 21 2007, 08:21 pm
hi vinay.........
i understand your points now..
in your case........
first of all u need to build/hire an ip server....
start send data in ip- packets log this data in to a database..... on your server.... use this database /integrate with your application....

u said..

Missing factor in my case is Fact that i do not have any IP addresse to experiment with

so i wud suggest go for smtp..

u r using airtel..

connect to airtelgprs.com

pick any smtp service provider.. yahoo.. google or search the net for other free smtp providers.....
now send data thru mail....

write a code (java) to download these mails (reading header of those mails).....
transfer tha data into xml/txt format and link to database.........

Fri Dec 21 2007, 08:23 pm
and where is the attatchement cudnt find it...???
Fri Dec 21 2007, 10:37 pm
Thanks for reply .
"send data thru mail...."

Logically my gprs modem should connect to website say Yahoo by entering ip addresse of yahoo in the at command syntex and now how we can forward email id and password then data into it . This way i can at least check that i am able to send my data to my mail using GPRS .For the moment this is logical and practical approach .I think i need to study SMTP further .
If you can refer to my attachment posted earlier , it will be a great help in proceeding further if you can let me know how can send mail . At the moment i am least bothered about reading mail hence data . Now my focus is on transmission of data from mcu and modem to mail server .
Looking forward for help.
Fri Dec 21 2007, 10:41 pm
By attachment i meant Hyperterminal screenshot posted by me earlier.
Sat Dec 22 2007, 02:17 am
vinay i have worked one different modems before... still the commands are almost same.....
cud u please post the command set / datasheets....
it wud help me give the exact guidelines.........
one thing id sure u can send mail ... i cud give u routine once i get the exactdaata sheets.........
one thing more did u get this modem thru a lot say 100 or is it available as a single peice.. plus cud u tell us the cost of a single modem ???
Sat Dec 22 2007, 10:04 am
Hi Shyam,

Please find datasheet attached with this replyl .

I have bought two modems for my prototype . Each costing around Rs 4500/ from Pulsar everything included . I have received quotations for this at about $ 26 for 1k SIM300 modules units from china.

I hope this satisfies your querries.


Sun Dec 23 2007, 10:50 pm
hi vimay ,,
ever heard of wavecom..??

they also provide GSM modems with free softawre support.....

they have an arm controller built inside... plus they provide a software suite Open-AT
developed by infosys as support for their modem.. the language used for that suit is our loved C

the modem has 2 serial UARTs plus ADC I2c SPI and many GPIOs ..
they aslo provide sample codes.. which are easier to understand and then implement....

i've done this SMTP with one such modem.. not with this SIMCOM modem.. i've arranged one myself.. but i think it wud take some time...

one more thisng this wavecom unit will cost u much less than 4500/- !dance

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