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Topic: Which GSM/GPRS/GPS shield do you recommend? (Read 1 time) previous topic - next topic


Sep 22, 2018, 05:34 pm Last Edit: Sep 22, 2018, 05:35 pm by ThresholdEngineering
I am looking for the most cost-effective cellular solution that will work with all current US cellular networks.

The project is a send-only Iot device that will send a few lines of information (far less than this post) only if a specific and rare safety condition occurs. In the lifetime of the device there is only a very small probability that it will ever be activated.

It is important to note that once development is complete, hundreds of these devices will be manufactured and deployed in the field, so cost is a critical consideration.

There appear to be many shields available, but the ones that say anything about the generation all seem to be 2G? The more I read the more it looks like this is only 2G which is either already obsolete or will be in the near future, but no definitive answer anywhere.

It seems like 4G LTE is overkill for the device and minuscule amount of data being transmitted, and the 4G shields I've found are far more expensive than than the more common 2G shields.

I am confident I can make the technology work, my question is which technology best suites the project without driving up the cost.

Lastly, although I'm not adverse to soldering, I would prefer a stackable shield rather than have to make them up. I can do a 1-off if I need to, but from a cost standpoint making up hundreds of custom boards will be out of the question.

Thank you in advance for any suggestions.


To confuse things even more, I'm finding shields that say they "receive" data from the 3G network which strikes me as odd.

Are there devices that ONLY receive?

It makes no sense but before I shell out the cash I need to be sure!

I found this which appears to be a good option: https://www.mouser.com/new/dfrobot/dfrobot-sim7000c-expansion-shield/


The dfrobot-sim7000c-expansion-shield is looking better and better.

Does anyone have experience with this board?


Further research is showing not all SIM7000 boards are the same.


It looks like SIM7000A will work in the US but then there's CAT-M1 or NB-LTE 

For my project it looks like the NB-Iot is more appropriate, but it's hard to find out if that's actually the best choice.

Maybe SIM7000 isn't actually the best chip anyway this quote on the page above makes me a little uneasy:

"...the SIM7000 does not operate on traditional LTE, although CAT-M does use existing LTE infrastructure "

This is getting more and more confusing!


THIS is actually quite helpful !!



2G modules are cheap, check SIM800L or SIM900. The problem is 2G will be shut down soon (some countries have already shut down 2G) and are power hungry (but since you will send a few messages, shouldn't be a problem). Setting a HTTP webserver that receives a message and stores it on a database is very easy to do.

NB-IOT / CAT-M is the future, but it is a new technology, for now it has low coverage (only in bigger cities?) and there are no great libraries to work with it. There are some modules available, check SIM7000 or SIM7020.
Setting a a webserver is more complicated since you have to use sockets to deal with TCP / UDP data.

Share with us your progress.

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