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Topic: Which GSM/GPRS/GPS shield do you recommend? (Read 8045 times) previous topic - next topic

ThresholdEngineering

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.

ThresholdEngineering

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/

ThresholdEngineering

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

Does anyone have experience with this board?

ThresholdEngineering

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

https://github.com/botletics/SIM7000-LTE-Shield/wiki/Board-Versions


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!

ThresholdEngineering

THIS is actually quite helpful !!

https://www.whistleout.com/CellPhones/Guides/cell-phone-networks-and-frequencies-explained

geologic

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.

micromedia65

Hi.
I did extensive work with the SIM800 and SIM900 in South Africa. I now emigrated to New Zealand, but they don't have the 2G network.
What this means is that I have had to find a SIM that I can use (Mainly for SMS texts for my purposes).
SIM5320 will work on 3G network, but very costly.
I found the SIM7020E and SIM7020C.
TAKE NOTE: In New Zealand, I would have to use the 7020E, as it has the extra bands necessary for my purposes, and I think in your case, would work for you.
Also, it uses almost the same AT commands as the SIM800 / SIM900 that I used before.

lastchancename

#7
Mar 21, 2020, 04:49 am Last Edit: Mar 21, 2020, 04:51 am by lastchancename
I've been using SIM5320 for several years, but they're a 3G chip, and some regions (here in Australia), have already scheduled future shutdown of 3G. (2G is long gone).

The US is of course different, but I've recently been testing out SIM7600C modules successfully.
They are a bit slower to connect, possibly due to scanning more bands, but once they're connected, they seem to faster in every control activity, and support up to 400Mbps (ideal).

There are several 7600 variants, you'll need to identify which one is targeted at the US market, carriers and bands.
Experienced responders have a nose for laziness, (they were beginners once)... Sure, there are trolls, chest-beaters, and pretenders - but the help you'll get here is about as good as it gets - if you try to help youself!.

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