Well, maybe this is impossible or is a stupid question but let me ask..
I would like arduino to send/receive SMS (eg, to monitor temperature in a remote place from home). I've seen there is special hardware to do so, like the "Siemens MC35 Terminal". But I most of us have a old cell phone arround so I wonder if it is possible to use it to do so.
Thanks.
Assuming your old phone is AT-command compatible, it's not hard to get the arduino to send a PRE-DEFINED sms. You just say send sms stored in a memory location. I can't remember the AT-ccommand for that off the cop of my head, but it's not hard to find using the AT-command set. It something like AT+CMGR1 to send a message stored in location 1
If you want to create an sms every time, say with a real time value of a variable, it gets a lot harder. You've got to create an sms in this wierd format called PDU. There are quite a few references out there, but I couldn't get it working
http://www.activexperts.com/activsms/sms/pdu/
If you get it working let us know.
Even the AT-command seems difficult to me 
How do you connect the phone ? Is there a serial port or something ?
Really it's easy... but i did grow up in the era of 1200 baud modems, using at commands to dial, answer and update settings. ah BBS days....
Yes you need a serial cable... most old phones have them, or you can or used to be able to buy them. check ebay for your phone. nokia 5110's are a classic for this type of application, I use a sony erricsson t300. I can definately recommend the older sony's for the job.
Actually thinking about it, you don't need the cable if you are willing to do a bit of hacking. just find out which pins on the phone's conenctors are the rx and tx, and solder wires onto them, and connect them to the arduino's serial pins. Check your phone works at TTL levels (old sony's do). a good site for pin outs is pinouts.ru
Thanks!
As you said, in pinout.ru I found this schematic to adapt the phone to a 232 port:
http://pinouts.ru/CellularPhonesCables/nokia_dku-5_cable_pinout.shtml.
To me, this means that the phone uses low tension levels. Do you think they are TTL?
What about baud rate, parity, etc ? How can I find it ?
Yep, looks like your phone uses TTL levels, same as arduino.
I'd guess 9600 - N - 1, kind of a default setup. You aren't going to hurt anything getting it wrong, just keep trying till it works.
Yep, looks like your phone uses TTL levels, same as arduino.
I'd guess 9600 - N - 1, kind of a default setup. You aren't going to hurt anything getting it wrong, just keep trying till it works.
If I understand, the easier way to try is use the serial port of the Arduino, but to do so I'll loose the serial output to the PC. Do you think it is a good idea to buy a Nokia - 232 cable and first find out what to do from the PC, then implement it on the arduino?
Can't hurt - and it's cheap, what, $10 maybe?
Also once you have it working you can chop up the cable and use the end of it rather that soldering onto the phone.
You know there are examples of software serial ports ot there? I think they should allow you to communicate to the phone and still have the computer communications available for debugging.
You know there are examples of software serial ports ot there? I think they should allow you to communicate to the phone and still have the computer communications available for debugging.
No, I didn't know. I thought it was only one serial port. Will look for it, thanks
There is one hardware serial port, you can have slowish software serial ports however.
A software serial port should be fast enough for talking to a mobile.