Questions for GPS and GSM 2G/3G/4G

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deanfourie

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#284417 20-Apr-2021 22:12

Hi Guys! I am working on a new IoT project and have a few questions.

I would like to know how I can use a GPS module without the use of a SIM card. I do believe this is possible with the use of eSIMs?

If so could you please explain this process and how it works, what networks it works on and how this can be configured. Is this done on a separate microcontroller or on a uBlox chip itself?

Also, can this be configured to use the 2G/3G/4G networks?

I would like to communicate with this device over MQTT and pull location data from a dashboard such as thingsboard.

So far im looking at the SimCOM SIM868 module which I believe is compatible with a wide band antenna.

Thanks in advance.

SomeoneSomewhere

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#2695499 20-Apr-2021 23:04

GPS itself is a receive-only system. A uBlox module will happily operate with no SIM or cellphone network connection whatsoever, and can tell your microcontroller exactly where it is.

However for your microcontroller to tell something else where it is, you will need a cellphone radio, which needs a SIM card, or possibly an eSIM but you still need to top up etc. and it will probably be a pain.

You could also use some other method to send the information like WiFi, bluetooth, some other long-range radio system, or even just an LCD screen.

deanfourie

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#2695519 20-Apr-2021 23:19

Thanks for the reply.

I just bought this device. Simply power it up and visit the cloud website, enter a serial number and the device is online.

How is this acheived?

Images attached.

Thanks

SomeoneSomewhere

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#2695520 20-Apr-2021 23:21

Yes, that probably needs to be set up as an eSIM device.

deanfourie

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#2695522 20-Apr-2021 23:39

My question is how are they doing it?

How can I acheived the same result?

There is no separate antenna for GPS and GSM, where even is the GPS antenna?

SomeoneSomewhere

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#2695524 20-Apr-2021 23:54

GPS antenna is likely the large square cap that the label is on.

Images are not good but you have at least three large ICs any of which could be a micro, a cellphone radio, or a GPS receiver.

There's also enough pins at the bottom that the intent could be to have an off-board SIM socket, though that would be unusual.

frankv

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#2695809 21-Apr-2021 10:01

http://www.simcom.com/product/SIM868.html says it has an antenna interface. My guess is that the black wire is, or is a coax cable leading to, the antenna.