3G vs 2G cellular module for a professional power sensitive GPS tracker?

[maryammagdy]

I'm confused upon whether to choose 3G module or 2G for sending GPS data to a remote server for a battery-operated tracker for a professional application product. From the datasheets, I noticed that the 2G modules consume almost half the power of the 3G. I've tested the performance of a Telit 2G module and so far I think it's doing fine but I still wonder if they're reliable and would appreciate some advices if anybody has experiences in such field.

 

[JonSea]

One big consideration is how long 2G networks will be around. That depends on where you are, but 2G viabilitycould be very short.

 

[Ramussons]

For GPS tracking, 2G is as good as 3G, but with a lower power requirement.
But as mentioned in the previous post, how long will 2G networks continue.....
Get 3G modules which are backward compatible with 2G so the setup can work even when 2G disappears.

 

[KeepItSimpleStupid]

Agree with what everyone said here. We are up to 5g. I might contact service providers in your area and ask their advice.
i.e.
Is 2G recommended for new designs? You would like to use it because of the low power requirements.
When do they anticipate ending 2G service?

 

[be80be]

2g is gone you can't even find slm cards for it I have a new 2g I can't find anyone to sell a card for it

 

[Ramussons]

2g is gone you can't even find slm cards for it I have a new 2g I can't find anyone to sell a card for it

Why not? A 3G sim should work in a 2G phone - if there's a 2G network.

 

[be80be]

Where do you live in ky you can't get 2 g sim and I made mistake got a 2 g only shield for arduino there is no one here that sales them that will work.
Out of the city my phone shows 2 g sometimes but it don't even like to use it.
I've check att they have nothing in 2 g

 

[Nigel Goodwin]

Am I missing something here?, isn't 2G just the standard fallback for when 3G is too weak, and likewise 3G is the standard fallback for when 4G is too weak.

Have you actually tried the Arduino board with a SIM in it?, and see if it works or not - I've never even heard any suggestion that SIM's are xG specific - and 2G works fine on everything here.

 

[be80be]

Yes it will not work on stuff that's 2 g only if it was 3g or 4 g it would work.
But the I'll post it the one I have is useless
Because it's 2 g only
I tried a AT&T data only and text but like said even with the phone it no longer shows any 2 g where I live

 

[be80be]

My problem is not the sim there is no 2 g here is what AT&T told me it's 3g 4 g LTE and now there even putting g5

 

[JonSea]

I looked at this a few months ago. There is some 2G service in the Seattle area, but it's all scheduled to be terminated soon. T-Mobile looks like the best bet, with service guaranteed to 2020 - a pretty limited time frame.

 

[be80be]

Guess I'm the luckly one there is no 2g here and seeing t-moble don't own no towers so the one's they using have no 2g

 

[JonSea]

I built some boards using 2G cell modems (his circuit design) for a guy in Nicaragua. It was frustrating not being able to test them. I hope he looked into 2G longevity in his country!

I do love T-Mobile though. We make frequent trips to Canada and once in a while to Mexico, and my phone just works. No extra charges. No settings to change. The only impact is a text message that says "Welcome to Canada. No extra charges apply."

 

[be80be]

I have T-mobile I like it too but it don't work with a SIM900 On the flip side tho It will get the right stuff back show the thing has network sig and is on T-Mobile
But when I send a text it don't send I show it has a working number.

I'm have a play with it soon and try something I just read that maybe get T-mobile to work.

 

[JonSea]

Are you using something like the Neo-6 modules? Please let me know if you get one of them working.

 

[Nigel Goodwin]

I have T-mobile I like it too but it don't work with a SIM900 On the flip side tho It will get the right stuff back show the thing has network sig and is on T-Mobile
But when I send a text it don't send I show it has a working number.

I'm have a play with it soon and try something I just read that maybe get T-mobile to work.

I'm currently sat about a foot away from a SIM800L module, it's connected to a PIC 18F26K22, which is reading a DHT22 sensor, displaying the temperature as a graph on a TFT module, and sending the temperature and humidity data via GRPS to a MYSQL database running on my website. At the moment this is pretty well a 'proof of concept', in particular I'm wanting to find out how much it costs to do this - but the answer seems to be very little - the 'standard' way of doing this sort of thing was via txt messages, but that is pretty expensive, so GPRS looks to be a LOT cheaper. It ran for 8 hours the other evening (until the battery went flat, I was making no effort to conserve battery power), and uploaded data every 5 minutes - I checked the credit on the SIM card (in fact I checked it on two cards, as I'm not sure which one I'm using ) and after 8 hours the credit (on either) hadn't changed. Checked the details of the service provider they charge 5 pence per megabyte, and 5 pence per txt, so it's vastly cheaper via GPRS as I'm only sending a few hundred bytes (if that?).

Incidentally, we have a number of 'loggers' out there for customers, that send back weekly meter readings via txt messages - which we have to 'top up' the credit for every now and again. They also require occasional battery replacement, which are 2 x ER26500 Lithium, with a 'BEST' capacitor across them, as they have quite high internal impedance and can't supply the high current pulses required by the GSM modem.

This talk of ending 2G, and even txt messaging, would cause an awful lot of chaos - as there's HUGE numbers of remote devices out there, most of which use either txt or 2G.

What do smart meters use?, are those 2G?, 3G?, any G?, or even txt messaging?.

BTW, here's a picture of my test setup, on a JLCPCB board - the small chip above the modem is a dual FET, used to switch power to the modem board, so it can be completely turned off for power saving. The missing SM IC is for an I2C memory chip.

 

[JonSea]

Nice work Nigel.

If 2G goes away, it certainly seems to put all the cheap cell modems out of business.

Where I asked Bert if he was using a Neo-6 above, I made a mistake. The Neo-6 is a,GPS module. I meant one of the SIM modules.

Here is a picture of a data logger circuit board I designed for a poster here. He wants to use a collection of modules (SIM cell modem, GPS, NodeMCU, etc) to accomplish his goals (which I am not at liberty to discuss). Initially, I thought this was kind of silly, but it allows him to accomplish his goals inexpensively and to be able to duplicate the board at will with a minimum of soldering skills. It makes sense to use this approach until a custom design is feasible.

 

[Nigel Goodwin]

He wants to use a collection of modules (SIM cell modem, GPS, NodeMCU, etc) to accomplish his goals (which I am not at liberty to discuss). Initially, I thought this was kind of silly, but it allows him to accomplish his goals inexpensively and to be able to duplicate the board at will with a minimum of soldering skills. It makes sense to use this approach until a custom design is feasible.

To be fair, that's pretty well my technique as well - you can buy the modules for considerably less than the chips (or the inductor in the case of SMPSU's), it seems silly spending more money to make it more complex to assemble - however, I did use an INA219 chip rather than a module in a recent project, but I did use three PSU modules for cost reasons. To be fair it would have been cheaper to use the module, but the INA219 is easily available in the UK, and not 'much' more expensive than the modules.

The existing loggers we have out there use a WISM0218 chip, which is larger and considerably more expensive than the entire SIM800L modem board, in fact the SIM socket that goes with the WISM chip is larger and more expensive than the SIM800L board

The WISM board is also entirely surface mount, this makes it much more difficult and time consuming to assemble, as we only manufacturer small numbers, so have to hand assemble the PCB's - hence our desire to use through-hole components where possible.

BTW, what's the little 8 pin chip near the opto-coupler?, presumably a memory chip?.

 

[JonSea]

I don't recall the exact part number of the chip, but it controls power to the GPS module. The SIM module can be commanded to a low-power state, but the NEO-6 dosen't have a sleep mode, so I used a switch to control power to the module.

 

[Nigel Goodwin]

I don't recall the exact part number of the chip, but it controls power to the GPS module. The SIM module can be commanded to a low-power state, but the NEO-6 dosen't have a sleep mode, so I used a switch to control power to the module.

Right, it's possibly a dual FET like I used?, or you can get specific low power switches intended for USB switching, but they aren't high enough power to switch a modem - pity, I was quite excited when I discovered them.