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Topic: Which GSM/GPRS module: SM5100B cellular shield vs. SIM900 IComSat shield? (Read 3 times) previous topic - next topic

tobek

Hi folks,

I'm trying to decide what cellular shield to get for my Arduino Uno, and whenever I search for information about any of the options, all I get are forum posts about people having problems with them. I'm fairly new to electronics so I'm finding it hard to judge them. Here are links to the two I'm considering:

SM5100B: http://www.sparkfun.com/products/9607
SIM900 IComSat: http://iteadstudio.com/store/index.php?main_page=product_info&products_id=413

The latter is much cheaper than the former, but seems to have more forum posts from people having problems. Also, this post (http://arduino.cc/forum/index.php/topic,80645.msg706190.html#msg706190) says that the SIM900 requires a 12V 1A power supply. Is that possible to do using an Arduino Uno and USB power or a 9V battery?

Any general thoughts about which is likely to be easier to use, and what I would get for the SM5100B shield being twice the price, would be very appreciated. Thanks a bunch!
Ideally, if anything were any good, it would be indescribable.
- Edward Gorey

tobek

Bump please! I at least want to know if the fact that the SIM900 needing 12V 1A power supply precludes it being used on an Arduino Uno. But I'm all ears on any thoughts on the two shields in general. Thanks.
Ideally, if anything were any good, it would be indescribable.
- Edward Gorey

PaulS

Quote
I at least want to know if the fact that the SIM900 needing 12V 1A power supply precludes it being used on an Arduino Uno.

No, it doesn't. It does need a separate power supply. The Arduino can not supply anywhere near that much current. The grounds need to be connected.

tobek


Quote
I at least want to know if the fact that the SIM900 needing 12V 1A power supply precludes it being used on an Arduino Uno.

No, it doesn't. It does need a separate power supply. The Arduino can not supply anywhere near that much current. The grounds need to be connected.

Ah, well, assuming OpenElectronics is correct about this, that rules the SIM900 out. Seems like the SM5100B expects 3.3-4.2V and up to 2A, which seems more feasible. That about makes the decision for me - cheers.
Ideally, if anything were any good, it would be indescribable.
- Edward Gorey

dhunt

The datasheet for the iteadstudio SIM900 shield you linked says it wants between 9V to 20V supplying at least 2amps.  From the schematic you can see it expects this to be supplied on the VIN pin from the Arduino. http://iteadstudio.com/store/images/produce/Shield/IComSat/icomsat_DS1.2.pdf, http://iteadstudio.com/store/images/produce/Shield/Module/GPRSmodule/GPRS_module_SCH.pdf.

The datasheet for the SIM900 module says it operates on a single supply voltage between 3.1V and 4.8V and that the peak current during transmit bursts is 2.0 Amps.  The shield takes care of converting the VIN supply to a voltage within the range required by the module.

So you will need at least a 9V 2amp supply for the Arduino with this shield attached.

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