B4R Question LoRa and RF transceiver Vs GSM (need advice)

[Cableguy]

Hi guys,

I have a project on my virtual drawing board that will call for the use of 2way long range communication.

Basically I will have a "master" device that will control a "Slave" by sending small packets (6 or 8 bit). The slave will then acknowledge the received message.

This is not problematic...
My issue is, the slave will be placed inside a closed metal cabinet and the master can be a few hundred meters away, inside buildings.

I know LoRa can achieve a 1km+ distance in open field, line of sight, at 433Mhz, and the same goes for the RF24L modules...

But, due to my specific needs, should I consider a GSM based solution (b4a app + B4R)?

Anyone has any experience with RF modules and their range in real life apliapplicat?

Thanks in advance

 

[Erel]

I don't have any real experience with LoRA. GSM is a good option if you know for sure that there will be cellular coverage in the deployment site.

 

[Cableguy]

I am inclined to do it that way, but since RF modules are so inexpensive, I thought I would ask

 

[JordiCP]

LoRa itself is just one of the possibilities. It can range even 20Km open-air and even more with directional antennas. From what I remember a good and clean antenna path and also denoised power supply is key to optimize it.
You only need to 'play' with the several parameters such as (from what I remember) speed, bandwith, spread factor and others....which will affect latency and range.

I have programmed modules from HopeRF and just these days fighting against Microchip RN2483 for LoraWan (which I am still figuring out how it works and is not needed for point-to-point scenarios).

My issue is, the slave will be placed inside a closed metal cabinet and the master can be a few hundred meters away, inside buildings.

May sound obvious, but the antenna will be out of the metal cabinet right?

As you say, being so inexpensive, I would buy a couple of them to play with.

 

[Cableguy]

Hi @JordiCP,

Unfortunately the whole assembly will be placed inside the cabinet (FTTH PMZ). I have tested a kind of "worst case scenario" by placing one of my Motorola 433Mhz walkies handset inside the closed cabinet and having the other in a nearby (+-300m) building staircase on a 3rd floor and the reception was fairly good.
GSM has a big advantage, as every company collaborator has a smartphone and coverage is fairly good.

To give you guys a better idea, the project objective is to allow a field technician to do visual tests by sending a laser light from the PMZ to the PBO (Floor Box) so to test optical continuity.
As we do now, the technician has to do several trips to the PMZ and back (up to 500mt distances) to switch connectors.
My project would ease this as it would allow the technician to connect up to 24 optical connections and remotely activate/switch the active connection.

 

[Cableguy]

Hi guys

So, I decided to go the GSM route, and ordered this thing.
Any problems I should be worried about?
It seems quite straight forward, but never worked with GSM before...

 

[JordiCP]

Nice one!

Perhaps an SMS-based protocol could be the best choice depending on your protocol needs (activate-deactivate-report)
Or, as it is also GPRS, if the SIM has a public IP (usually paying), you could also build a server-less socket-based solution.

The only thing to worry about: these devices usually admit a wide power range. Unless it has a built-in regulator for the modem part (don't know if your board has it), never feed it near the low limit of this range. There are very short but heavy consumption spikes when negotiating with the BTS that temporarily can decrease this voltage if the path is not good enough. This leads to the modem normally powering off and/or rebooting itself, and most of the times the microcontroller behind it will not notice it, leading to strange behaviours.

 

[Cableguy]

Thanks for the heads up!

For testing purposes I will do it "indian" style, with connection wires and a Bat-Pack from a power-drill, just to check doability.
As for a protocol, I plan to keep it as simple as possible and use a text sms based system

 

[BillMeyer]

@Cableguy

Can I upset the apple cart please ?

Look at this link - It could solve your problems easily I think.

and then here (link)

Oh, and by the way, it's French - discovered from Sunny South Africa - Enjoy your research.

 

[tigrot]

@Cableguy

Can I upset the apple cart please ?

Look at this link - It could solve your problems easily I think.

and then here (link)

Oh, and by the way, it's French - discovered from Sunny South Africa - Enjoy your research.

Hi Bill, unbelievable! Is it real? Did you test this service?
Mauro

 

[BillMeyer]

@tigrot

I am waiting for my first boards to develop on and my first "Panic" buttons for security of old people and disabled people. It should all arrive this week.
There is so much potential here - I am also waiting for an OBDII device that works on SigFox - monitor your car without a GSM signal !!

I'll keep you updated.

 

[tigrot]

@tigrot

I am waiting for my first boards to develop on and my first "Panic" buttons for security of old people and disabled people. It should all arrive this week.
There is so much potential here - I am also waiting for an OBDII device that works on SigFox - monitor your car without a GSM signal !!

I'll keep you updated.

Thank you!
I've been developing a similar device for Altzheimer unpaired people for years. Would be very nice to get 140 position every day, to study habits and probable solutions when they are missing.

 

[tigrot]

There is a Company in Italy (Axelelettronica) which had a product "smarteverything" which has been discontinued. I'm asking what happened,

 

[Cableguy]

There is a Company in Italy (Axelelettronica) which had a product "smarteverything" which has been discontinued. I'm asking what happened,

Going off-topic!

 

[tigrot]

I love to stroll around in conversations! Forgive this old man!

 

[Cableguy]

No problem, I just want to keep it clean for further discussion. Off-topic post may lead to monipolization of the topic in a less productive way