Have a look at the second picture! It becomes a "belly-SIM"!
Btw. the Bluevia / Telefonica shield mentioned in reply #2 in this thread will be "available in the following days." -- This was a information from the BlueVia Community Support.
FWIW, I have had very good luck with the Seeedstudio version. Geekonfire also has a model.
Whatever module you want to consider, research the underlying chip and libraries! For the sim900 there are a number of libraries and examples out there that you can follow along. The AT manual also gives you the commands you'll need to use in order to start a GPRS connection, send an SMS, etc
Also, depending on where you live, it might make sense to use a M2M Sim card, ie one designed specifically for applications like this one. I had good luck with the unit from embedded works.
I asked BlueVia / Telefonica about the deliver date of the new Telefonica-Arduino-GSM shield again. Announcement / purchase see: https://bluevia.com/en/page/tech.arduino
The really friendly support told me they had some problems with the launch and the release date got delayed. If everything goes as expected, the new release day is the 22nd October. I assume 2012, the year was not specified explicit.
Again one month is gone and still no shield available neither by bluevia nor by an other distributor. :-/ Will this shield also be available in the official Arduino store http://store.arduino.cc (without SIM)?
PaulS:
Seems unlikely, since the shield is not made by the Arduino people.
At http://labs.arduino.cc/GPRS/Index David Cuartielles and Gianluca Martino are mentioned as key people in the GPRS shield development and they are also labeled as "co-founders of the Arduino project" - so I thought the hard- and softwarepart would be covered by Arduino people. But perhaps this is an old level of information.
Now - 23rd Dec - the "coming soon" bage on the bluevia website is gone and the buy button is linked to the Arduino store. But there is no product page, no price, no order info for the GSM shield. Has anybody from the Arduino team further information what's going on in this case?
All I can say is that the SIM900 shield from SEEEED works great. Why keep waiting when there are quad-band alternatives out there that will work pretty much world-wide?
I emailed BlueVia last week regarding availability in Australia for their new Arduino GSM shield, the reply I received indicated that it was only available in certain international locations: http://bluevia.com/en/page/tech.arduino.service and when it becomes available the shield can be purchased through the Arduino Store.
I was given no indication of eta but I was told that using a SIM card other than the one supplied from BlueVia would not be supported.
Has anyone had problems with connecting to the GSM network? I have a deal with one of our national operators. When the SIM card is inserted to a normal cell phone, it connects without any problems. But, when inserted to Geetech SIM900 GPRS shield, it has difficulties to register to the net.
On my desk it connects only occasionally, in our kitchen it connects better. Seems, that the shield needs really strong signal to register to the net. Last week in another city it connected every time without problems. What can I do to get it registered more reliably? This leads to antenna related issues, but everything seems to be ok. It has a removable antenna and from the antenna jack a thin lead goes to the board to another really small connector.
Unfortunately a bit more expensive than I expected. I heard in an interview that the price would be well below already sold GSM modules, but it is rather more expensive than existing shields. I am also a bit disappointed that the power consumption seems to have the level of already existing shields.
Does anyone know if this "official" GSM shield works fine with the Arduino MEGA 2560, or does it need some modifications like the other shields?
I'm not sure if you ever figured this out but the documentation for the official Arduino GSM Shield includes the following instructions for using with a MEGA2560/ADK/Leonardo- http://arduino.cc/en/Guide/GSMShieldLeonardoMega
My problem has been the use of serial data as the gsm shield uses SS for its own communication. If your trying to send data from another serial input (such as GPS) the answer appears to be complicated to say the least...