IoT over Cellular Service/Hardware Recommendations?

Visitor · Jul 8, 2021

I find myself soon to be the owner of an RV (motor home), which will be stored off-site.

I would like to do some simple remote monitoring, including temperature and humidity, battery voltage and various alarm contact-closeures. To this end, an IoT over cell seems like it would be the best approach.

What I have in mind is a micro to squirt out info to a cell modem. AT&T has an unlimited data program for $60/year which seems reasonable.

Has anybody here done this? Recommendations for cell modems and providers?

Pommie · Jul 8, 2021

I haven't done this but would guess a cell phone with access point enabled will just be seen as another wifi network and a wifi enabled board would be able to use it. I have a spare cell that was used for this a few years ago and it cost ~US$50. Cell modems seem to be becoming rare or, when available, expensive.

Mike.

Visitor · Jul 8, 2021

Hmmm. My immediate thought was "But cell phones don't have a UART input anymore" (I had an AT&T phone way be when that did)....but Bluetooth or WiFi is a definite possibly.

Nigel Goodwin · Jul 9, 2021

You can buy an ESP32 module that has a SIM800L modem built-in, nice and easy to use, and dead cheap.

Visitor · Jul 9, 2021

I did see a version of that, but the flavor of cell modem it had wasn't one supported in the US.

Nigel Goodwin · Jul 9, 2021

Visitor said:
I did see a version of that, but the flavor of cell modem it had wasn't one supported in the US.

Shame, unfortunately all the low cost modems are old spec. 2G - but it's all that's needed, hence a lot of networks still support them (as there are millions of them out there still in use).

KeepItSimpleStupid · Jul 9, 2021

Visitor said:
What I have in mind is a micro to squirt out info to a cell modem. AT&T has an unlimited data program for $60/year which seems reasonable.

Huh?

Get Info About Data-Only Plans

Find out which data-only plan is right for you. Use your plan with a tablet, mobile hotspot, and other devices.

www.att.com

$60.00 per month, maybe?

I had a Motorola Razer. Really cool. The USB port could be a cellular modem. AT commands and all. You could easily connect to a PPP provider.

There are some tethering programs, but they do data differently.

You have to watch one device vs a network device. A real data plan can support a network. At one time, I did tricks that got me unlimited data to a computer because I had unlimited phone data. AT&T said "they fixed that". I don't have unlimited data on my phone.
Some routers can accept USB Cellular modem cards.

I miss clearwire.

Visitor · Jul 9, 2021

No, I really did not make an error when I said $60/year.

"Narrowband" cell service for IoT applications is extremely affordable. As little as a buck a month. The is for sending small amounts of data, like telemetry and alarm data, which is exactly what I need for my monitoring application.

Pommie · Jul 9, 2021

Here in Australia, we can get a 50Mb/month data plan for AU$1 (~0.70US$) per month. See second line, https://www.tpg.com.au/mobile Looks like this is being provided everywhere now.

Mike.

Nigel Goodwin · Jul 10, 2021

Pommie said:
Here in Australia, we can get a 50Mb/month data plan for AU$1 (~0.70US$) per month. See second line, https://www.tpg.com.au/mobile Looks like this is being provided everywhere now.

Mike.

I've started using ThingsMobile (from Italy) at work, simply because I was unable to find SIM's that worked any more - the older SIM's from the same networks work perfectly, but new SIM's from all the networks I tried wouldn't work - possibly the new SIM's no longer support 2G (while the network still does).

Diver300 · Jul 11, 2021

giffgaff (https://www.giffgaff.com/) don't have a monthly charge. You have to use some data every 3 months but the rates are very cheap for any sort of IoT use.

I've been using the Telit GE863, GE864 and GE864 modules for some time for vehicle tracking, which includes a lot of additional information along with the position and speed.

Here is an example of what can be done. The speed came from a GPS receiver and the fuel level by reading the CANbus:-

Visitor · Jul 11, 2021

Thank you. This is what I'm looking for.

How do you receive the data? I have a SIM coming from a US company (whose name escapes me at the moment) and they talk of a console ap and APIs.

Nigel Goodwin · Jul 11, 2021

Diver300 said:
giffgaff (https://www.giffgaff.com/) don't have a monthly charge. You have to use some data every 3 months but the rates are very cheap for any sort of IoT use.

Except new Giffgaff cards no longer work - my old one is perfect, but the new one I got (among many others) is presumably blocked from 2G now. We were previously using Vodaphone cards, but the new ones of those no longer work either.

The Thingsmobile ones are specifically designed for data use, and don't even have voice capability.

Nigel Goodwin · Jul 11, 2021

Visitor said:
Thank you. This is what I'm looking for.

How do you receive the data? I have a SIM coming from a US company (whose name escapes me at the moment) and they talk of a console ap and APIs.

I do it by reading and writing data via PHP scripts and an SQL database running on an Internet server - this has the advantage that you can make a lot of adjustments in the PHP code, not needing access to the hardware. So keep the hardware/software side simple, and do the clever bits on the PHP side.

For example, we're providing remote readings from water meters, which provide a simple pulse output - historically the logger would count the pulses, do the required maths (based on how many pulses per litre etc.) and then send a text of how many litres/sec, litres/hour or cubic metres per hour had gone through the meter. This meant the receiver either had to 'wake up' occasionally, to receive instructions, or read them at it's normal transmit time.

I decided a GPRS system would be better, rather than texts, and that simply sending the pulse count is all you need to do - the required conversions are done in the PHP, and easily altered at any time you wish.

It's worth a look at these tutorials:

ESP32 HTTP GET and HTTP POST with Arduino IDE | Random Nerd Tutorials

Learn how to make HTTP GET and HTTP POST Requests with the ESP32 board with Arduino IDE. How to get values, post JSON data objects, URL encoded requests, etc.

randomnerdtutorials.com

ESP32 SIM800L: Send Text Messages (SMS Alert) with Sensor Readings | Random Nerd Tutorials

In this project we’re going to create an SMS notification system with the T-Call ESP32 SIM800L module that sends an SMS when sensor readings are above or below a certain threshold.

randomnerdtutorials.com

And plenty of others on the site.

Diver300 · Jul 11, 2021

Nigel Goodwin said:
Except new Giffgaff cards no longer work - my old one is perfect, but the new one I got (among many others) is presumably blocked from 2G now. We were previously using Vodaphone cards, but the new ones of those no longer work either.

I've been running some recent giffgaff SIMS on 2G, so I don't know what I'm doing differently.

Diver300 · Jul 11, 2021

Visitor said:
Thank you. This is what I'm looking for.

How do you receive the data? I have a SIM coming from a US company (whose name escapes me at the moment) and they talk of a console ap and APIs.

It's encoded in the URL. I send HTTP GET requests with a load of arguments on the address. They would be something like:-

GET /data/index.php?lat=52.45762&lng=-1.40367

In the index.php file on the server I have code that is something like:-
$lat = floatval($_GET['lat']);
$lng = floatval($_GET['lng']);
and then those values will get stored into a database.

I used many other arguments for various types of data, and the URLs get quite long.

Nigel Goodwin · Jul 12, 2021

Diver300 said:
I've been running some recent giffgaff SIMS on 2G, so I don't know what I'm doing differently.

How recent? - the one they supplied me, and all the other types, won't even work on the Arduino demos with the libraries - yet all the older cards still do (Giffgaff, Vodaphone and 1P Mobile). Basically you can swap cards between the modules, all the old ones work as before, none of the new ones do - other than Thingsmobile.

Diver300 · Jul 12, 2021

I registered a couple of giffgaff SIMs about a month ago, and used them on 2G cellular modems.

There are different ways of accessing the internet using the cellular modems.

A bit over 10 years ago, when I first started using the Telit GE863s, they were controlled with an 8 bit PIC. I used Vodafone PAYG SIMs. Vodafone were charging 1p per connection, which was expensive but OK unless fast tracking was needed. I had started to move onto Telit GE864s, controlled by a 16 bit PIC.

Vodafone changed the pricing, to 50p per day, which made them very expensive for vehicle tracking. They also changed something in the way that the cellular modems talked to the network. All the GE863s stopped working. We asked Vodafone, who said that nothing had changed.

I tried running a GE863 from the 16 bit PIC, and it was fine, so it was something about the way that the code for the 8 bit PIC opened a connection and sent data. I never fixed it, because the code was fine with O2 PAYG SIMs, and I couldn't change anything remotely, so any that were returned would get new SIMs anyhow because of the price difference, and then they would work fine.

About 6 month later, Vodafone changed back whatever it was that "hadn't changed" and all the remaining ones with Vodafone SIMs came back to life.

My point is that what is stopping you using the older SIMs may not be that they don't work on 2G, but that a different protocol is needed.

Nigel Goodwin · Jul 12, 2021

Diver300 said:
I registered a couple of giffgaff SIMs about a month ago, and used them on 2G cellular modems.

There are different ways of accessing the internet using the cellular modems.

A bit over 10 years ago, when I first started using the Telit GE863s, they were controlled with an 8 bit PIC. I used Vodafone PAYG SIMs. Vodafone were charging 1p per connection, which was expensive but OK unless fast tracking was needed. I had started to move onto Telit GE864s, controlled by a 16 bit PIC.

Vodafone changed the pricing, to 50p per day, which made them very expensive for vehicle tracking. They also changed something in the way that the cellular modems talked to the network. All the GE863s stopped working. We asked Vodafone, who said that nothing had changed.

I tried running a GE863 from the 16 bit PIC, and it was fine, so it was something about the way that the code for the 8 bit PIC opened a connection and sent data. I never fixed it, because the code was fine with O2 PAYG SIMs, and I couldn't change anything remotely, so any that were returned would get new SIMs anyhow because of the price difference, and then they would work fine.

About 6 month later, Vodafone changed back whatever it was that "hadn't changed" and all the remaining ones with Vodafone SIMs came back to life.

My point is that what is stopping you using the older SIMs may not be that they don't work on 2G, but that a different protocol is needed.

No, the older ones all work fine still, and always have - it was getting new ones that was the problem. Swapping cards round made no difference, the old ones all worked in all circuits, the new ones worked in none.

Do you know where your cards failed when they did?, at what point in their setup.

As I recall, mine all failed at the same point - AT+CREG?

Diver300 · Jul 12, 2021

Nigel Goodwin said:
Do you know where your cards failed when they did?, at what point in their setup.

As I recall, mine all failed at the same point - AT+CREG?

I can't remember at what point they failed.

I don't use AT+CREG?

I'll send a log if you want.

IoT over Cellular Service/Hardware Recommendations?

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