PIC and Cellular phone connection for SMS controlling

buneri · Joined: 23 Aug 2007 Posts: 14

I am working on a GSM base project first time.
I dont understand how i would start,
First i want to ask how can i connect PIC with any cellular phone, either i would connect it via cable or directly with cell by soldering?
Secondly what cell phone would be best for interfacing with PIC what should be my first step for testing.
Any guidance will be apreciated.
Thanks in advance.

Andreas · Joined: 25 Oct 2004 Posts: 136

Basically its a matter of having a serial connection to the cellular phone. I would suggest to test the functions before with a terminal programm from your pc , than if you know how it works start with the pic implementation.

But keep in mind, the hard part is to trap all erorrs which can apear at the interface. When You make it by hand an the PC its easy you see something didnt work you repeat the command, this you have to implement in the PIC programm as well.

I made such an implemenation it took me about 2 hours to get it run and then it takes more than a week to cover all possibilities to get all errors, Network oddities and special features to work.

best regards
ANdreas

jaime · Joined: 25 Nov 2005 Posts: 56 Location: Porto - Portugal

Hello
I try siemens c45 and ME45 and it works fine for me. But for SMS controlling it would be better that the mobile supports text messages.
I think the first step is connect the mobile to a pc and with hiperterminal or terminal try some at commands. Then go to the pic...

See my page. Hpe it helps.
Jaime
_________________
www.jagsilva.com

densimitre · Joined: 21 Dec 2004 Posts: 45

Well

1.- Most cell phone cables are USB type. Then you need implement a HOST controller on PIC, that is very complicated right now because pics are USB devices type.
2.- Then, try to obtain RS232 type cable to connect PIC to Cell Phone.
3.- Making tests using Hyperterminal, you will find that with AT command you would can implement a good communication model.
4.- To communicate PIC to Mobile, you have to plug a 12 or 9 volts to 7-4 pins of RS232 DB9 conector, this because RS232 cables have a internal level translator from 12V to 5 or 3 volts, depending of manufacturer (ericsson 5 volts, nokia 3.7 volts). If you connect only TX/RX pins, then you will not communicate with cell phone...
5.- Implement a #int_rda buffer application on PIC to receive data from cell phone to take action on this...

Read Handbook of hardware pinouts from http://pinouts.ru/ to obtain data of your cables...

Best Regards...

buneri · Joined: 23 Aug 2007 Posts: 14

Thanks for reply!
I have connected my Nokia6030 mobile with PC and try some AT Command but no response from the phone.
I have select 9600 baud rate, parity=None, stop bit = 1
What should i change?
Thanks

densimitre · Joined: 21 Dec 2004 Posts: 45

flow control: none

buneri · Joined: 23 Aug 2007 Posts: 14

Dear Sir,
I have change that too but no response.
One thing i want to ask is that "RS232 to ttl converter" is necessary while communicating mobile with PC through Hyperterminal?
Or it will communicate directly by just pluging the RS232 data cable of mobile into the PC serial port?

Thanks Again

buneri · Joined: 23 Aug 2007 Posts: 14

Also is there any need of cable driver for that?
If yes then is it also for PIC communications?
I m waiting 4 ur reply!
Thanks

Guest · Posted: Mon Oct 08, 2007 8:25 pm

Hi
1.- So, PC puts a 12 volt on pins 7 and 4 of DB-9 cable connector. It is from this power that cable obtain 5 volt to send TX/RX signal in TTL levels, that cable has internally a 12V to 5v converter, this is what it is a rs232 to ttl converter.
2.- You don't need a driver...

When yo connect the PIC with Cell Phone, you have to make that pin 7 or 4 can get power from somewhere to level converter work well...

So, you can use a MAX232 like a RS232 interface..

PIC <==> MAX232 <==> Cellphone cable (RS232) <==> Cell Phone