[SOLVED] GSM shield / cell module SM5100B destroying / burning SIM cards?

Projects Networking, Protocols, and Devices
1

Hi there!
I need remote monitoring of a few sensors, and reporting via SMS over a cellular network, so I started with this tutorial:
http://tronixstuff.wordpress.com/2011/01/19/tutorial-arduino-and-gsm-cellular-part-one/

Got the shield from a local reseller of sparkfun components - it comes with the Spreadtrum SM5100B-D GSM module - and got over the initial challenges:

  1. It came with a baud rate of 115200 when the Arduino UNO only supports 9600, this makes strange characters appear in the terminal. The solution can be found in the comments in the sparkfun product page - but if you run into the same issue and are stuck, feel free to ask;
  2. Install NewSoftSerial Library in a Mac (move the entire NewSoftSerial folder to Documents/Arduino/Libraries);
  3. Calling the module wasn't giving me the Caller ID, inputting the command AT+CLIP=1 solved this.

Now that everything seemed to work as expected, and just when I started to code my sketch... upon booting, the shield started to output:

+SIND: 0
---- instead of...
+SIND: 1

The shield is telling me that there's no SIM card inserted, but the card is there and properly placed.
This happens somewhat randomly when booting the Arduino UNO, and it's not related to the sketch that I'm uploading (because this happens frequently with any sketch).

So I try to use the SIM card in a regular mobile phone and, guess what? The phone isn't even able to boot up with this SIM card inserted!
Went to my service provider and got the SIM card replaced. I even asked if this was fairly common, they said "no, not at all". Hmm...

With the new card, everything was okay for 20 minutes or so, and then it happens again.
I remove the SIM card from the shield and insert it on the phone again - phone doesn't boot, again.
After 30 minutes, the phone was able to boot but said there was no SIM card inserted.
Only after a couple of hours, the phone recognized the SIM card again.

And then I place it again in the shield, boot up, it's fine, then after some operations it suddenly says "+SIND: 0", reboot and continues to return "+SIND: 0", then reboot again a couple of times and all is working fine...

What's happening???

It would appear as if the shield is burning / destroying the SIM cards and resetting itself at the same time, but why?
SIM card VCC reads 1.81~1.83V, shield Vin reads 3.99V - which is not the "ideal" 3.6V but totally acceptable (datasheet says Vmin=3.3V, Vnom=3.6V, Vmax=4.2V).

Arduino UNO R2 connected via both USB (to receive and send through the serial port) and external power adapter, regulated 9V 1A, GSM shield on top.

Already tried with four different SIM cards, this keeps happening randomly with any of them...

Any input will be immensely appreciated.
Thanks for reading.
Regards,
footswitch

2

external power adapter, regulated 9V 1A

You really should be using an adapter that will supply a minimum of 2 amps. Not saying that is what's causing your problems but if I were consistently blowing SIM cards on this shield I'd ask for a replacement!

3

Hmm... interesting point.
I thought 9V 1A should be able to handle the necessary peak current, because the module runs @ 4V.
Still, I'll try with a more powerful one.
And by the way, the module has been running error-free all day. Zero fried SIM cards.
When it comes to electronics, there's nothing I hate more than intermittent "bugs".

I really have no idea whatsoever if the module should be replaced or not. I suppose it should, to play on the safe side, but then I don't want to go nuts when the next module starts doing the very same thing (Murphy's Law says it will).

Thanks for the input :slight_smile:

footswitch

4

Hi, sorry for bumping this, but I don't fancy unanswered topics much - I like to get a definitive answer whenever I come across an old topic.
So I'm just passing by to close the subject.

The GSM module was indeed defective.
The shield itself was ok (it's a simple shield with few components).
A replacement of the module solved this intermittent problem.

Cheers!

5

Just a note to anyone who find this thread - the Sparkfun GSM shield with that Spreadtrum module can draw up to 1.42A in our experience in short bursts, so it is very prudent to use the 5V 2A power supply
have fun