Which is the "best" Arduino's GSM shield available ?

Good Morning, could you tell me which the "Best" Arduino's GSM to use ?

I've did an application and then the last part is Communication over GSM Shield, the shield need to be stable and 100 % working,

Thanks, Andrea

could you tell me which the "Best" Arduino's GSM to use ?

That depends on your criteria. What is best for you might be useless for me.

Ciao Paul, thanks for the answer … so I was asking this because since the moment are prototipe maybe time to time can happen some issues …

I didn’t have experience for that for this reason I was asking … I’ve seen that on internet there is a lot of different shield and I don’t know which is the best …

so, what i can tell you is : i will use the for notify a state when sensor will be triggered … the state will notify with SMS …

could you suggest from your experience which is the best ?

thanks
Andrea

Hi..

I have tried a good number and they all have there own quirks, I settled on the Siemans tc35 /tc 35i modules available from a good number of ebay sources but most come from SANSMART anyway. This is not a plug on shield its a complete module so 3 wires to arduino + 5volt supply.. Its configured as a DCE so no cross in tx - rx

The library software is quite poor but in my view most are anyway or they are overkill for your apps. I used the basic ideas in library to write a smple send Hayes system to test modules then wrote as part of a OEM develop,ent a full SMS and voice call library, the module is supplied with an adapter to connect mic/speaker, I have also interfaced a bluetooth head set.

The manual for the tc35 module is free and available on various sites and shows the flexability of the current firmware release on the modem.

Words of warning, many examples on Internet use delay based synchronisation of the sequence to the cell network, for sms send receive and also voice calls, although with some fiddling this can be made to work its highly unstable mechanism torely on, if you try your solution with an alternative carriers SIM the timing on cell replys etc., are governed by the cell equpmeny, celluar network loadings etc., so it may work one time then fail next time. You need to consider a sequencer driven by replys and or a watch dog timer probably derived by a time tick generated on the OVF interrupt on one of the spare timers on the Arduino.

The primary direct intefaces are RS232 and 3.3volt. Remove the RS232 convertor chip greatly reduces power drain and although the purests will say don't interface ttl 5volt levels to 3.3 volt levels unless you allow the arduino voltage regulator to go beyond its limit or inject a raw voltage after the arduino regulator it has always been the case I worked in semi conductor chip design for 30 years.. that 3.3 volt cmos will just limit the high by the shottky diode protection on an input and the 3.3 volt output is more than adequate to drive a ttl input beyond the logic 1 level.

If you are worried just wire a 100K resister in the output of the ttl in series to limit the voltage on the 3,3 volt device.

I power my systems via the gsm modem module let it regulate a 5 volt supply and feed this to the arduino raw voltage input.

You do need up to 2 amps at 5 volts during a conversation with the cell but only in brief bursts I use a 1.4 amp 5 volt supply and have yet to fry the supply invertor. I hace gsm based solutions running in about 30 systems supplied as one off OEM designs and just checked 22 of these have the Siemans modules installed, only one failure and that was infabtile failure after first switch on.

Hope this helps

8) 8) happy coding..

Thanks you for your replay,

could you indicate me the steps ?

I've tried to download documentation but there isn't nothing related to arduino ... I would like to know if is possible how to connect to arduino and work on that ...

since the moment is siemens seems professional ;-)

Thanks :-)