Connect to closest Central

RE: Connect to closest Central

awneil — Wed, 09 Oct 2019 10:20:23 GMT

So that's your design decision - not a requirement or restriction of using a mesh.

RE: Connect to closest Central

ran — Wed, 09 Oct 2019 10:12:10 GMT

" I will need to connect to each one of the nodes from a mobile phone and set\get configuration" - this is regardless of Mesh but operational , for example elec. meter S\N and initial reading .

This is per meter configuration and will have to be done using Tech, App running on iOS\Android

RE: Connect to closest Central

awneil — Wed, 09 Oct 2019 10:09:22 GMT

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central/213997"]So , If I'll be using Mesh , I will have to define a gateway that all nodes "publish" to him ?[/quote]

Yes - that is a standard concept in meshes

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central/213997"] I will need to connect to each one of the nodes from a mobile phone and set\get configuration[/quote]

Not necessarily.

You can provision over the mesh - again, a standard concept in meshes

RE: Connect to closest Central

ran — Tue, 08 Oct 2019 18:00:05 GMT

Just to complete the picture - the metering data goes up to the cloud. In the installation I've described - the star central is equipped with LTE modem . ( gateway )

So , If I'll be using Mesh , I will have to define a gateway that all nodes "publish" to him ?

Also - I will need to connect to each one of the nodes from a mobile phone and set\get configuration

(probably over NUS ) , will that be a problem ?

(I see that in latest mesh sdk, proxy node was remove from lightning client, available only on server ).

RE: Connect to closest Central

awneil — Tue, 08 Oct 2019 17:11:04 GMT

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central/213991"]Mesh provisioning of a new device seems pretty complicated last time I've tried it[/quote]

Are you thinking of the Nordic demo?

That is, of course, just a manual demo - you wouldn't do it that way for a real project!

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central/213992"]Mesh does not support Coded PHY ( at least officially ) [/quote]

That's true, but your alternative is entirely proprietary anyhow - so that shouldn't be an issue.

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central/213991"]Boss man wants this fast[/quote]

Don't they always.

The trouble is, you are basically re-inventing (a lot of) what a mesh already does for you - so, while you might come up with something that "works" in a basic case in the lab, transferring that to a fully reliable deployment in the field and covering all corner cases is a whole different ballpark ...

RE: Connect to closest Central

ran — Tue, 08 Oct 2019 16:42:52 GMT

Oh...also - key consideration.

Mesh does not support Coded PHY ( at least officially ) - which might be needed for more rural environment.

RE: Connect to closest Central

ran — Tue, 08 Oct 2019 16:42:02 GMT

About Mesh - Understood, I've been struggling with this for a while.

This is why I'm thinking a star will be better for this case :

1. The requirement is that an installation of a new peripheral will be EASY. Mesh provisioning of a new device seems pretty complicated last time I've tried it. Installation is done by Electricians.

2. This installation can be transferred to a battery operated environment, where I will have to add powered Friend-Nodes .

3. I hope I'm wrong, but the whole BLE mesh looks like it is meant at this stage for lightning projects.

4. Learning curve for Mesh ....Boss man wants this fast :)

RE: Connect to closest Central

awneil — Tue, 08 Oct 2019 15:48:29 GMT

Indeed - sounds like exactly the kind of thing Meshes were invented for!

and then you're not limited to there being just 2 "stars", or 2 Centrals in range, or ...

RE: Connect to closest Central

Mojo — Tue, 08 Oct 2019 15:19:14 GMT

I think a bluetooth mesh network would be a better choice for this.

RE: Connect to closest Central

ran — Tue, 08 Oct 2019 15:14:51 GMT

Hi,

Imagine 2 stars ( central connected to 4 peripherals ) .

Those 2 stars can overlap.

I'd like to add another peripheral to the 1st star. Both Central are in range, one will be further away.

So - I need the peripheral to automatically "choose" which central should connect to him.

This is for electricity meters monitoring in a building

RE: Connect to closest Central

Mojo — Tue, 08 Oct 2019 14:46:27 GMT

Any particular reason why you need this complication ? Why not just reverse it. 2 periph instead of 2 centrals, and the centra (instead of periph) decides which periph to connect to ? Wouldn't that be simpler ?

RE: Connect to closest Central

awneil — Tue, 08 Oct 2019 14:15:30 GMT

OK: so instead of the original proposal, where the Centrals decide between them before making any connection, you're now going to have the Peripheral connect to all Centrals, and then decide which connection to keep?

Which should achieve the same end.

The only slight downside is that it means more "intelligence" in the Peripherals - which is usually the most-constrained device.

It also means more radio traffic.

But these things may not matter in your use case.

RE: Connect to closest Central

ran — Tue, 08 Oct 2019 14:07:18 GMT

Since I have my peripheral connected to 2 centrals now, I can get the rssi of the connections , and then decide which connection I should drop.

I didn't think a peripheral can be connected to more then 1 central until today :)

RE: Connect to closest Central

awneil — Tue, 08 Oct 2019 13:55:47 GMT

That helps you with obtaining the RSSI value at each Central separately.

It doesn't help you with how one Central knows the RSSI at the other.

RE: Connect to closest Central

ran — Tue, 08 Oct 2019 13:46:14 GMT

I guess I can try this

Peripheral-Central RSSI

RE: Connect to closest Central

awneil — Tue, 08 Oct 2019 10:20:34 GMT

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central/213835"]"So you will need some kind of communication between the 2 Centrals ..." - this means that one is a central and the other one is a peripheral[/quote]

Not necessarily.

You might have non-BLE comms between them.

If it's BLE comms, use a SoftDevice which supports both Central & Peripheral simultaneously.

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central/213835"]roll switching[/quote]

* role

RE: Connect to closest Central

ran — Tue, 08 Oct 2019 09:40:42 GMT

awneil - Comment accepted - I've modified the question.

I understand that the central initiate the connection - this is why this is a challenge .

As you've mentioned

"So you will need some kind of communication between the 2 Centrals ..." - this means that one is a central and the other one is a peripheral , hence the role switching .

RE: Connect to closest Central

awneil — Mon, 07 Oct 2019 14:14:18 GMT

Also note that RSSI gives only a very course indication of distance - especially in an enclosed area like a room!

See numerous previous forum discussions!

The strongest RSSI may not necessarily be the closest!

So probably best if you just say, "strongest RSSI" - and don't mention distance.

RE: Connect to closest Central

awneil — Mon, 07 Oct 2019 14:11:26 GMT

It is the Central which initiates the connection.

Therefore, if only the "nearest" (sic) Central is going to connect, then each Central will need to know the RSSI of the Peripheral at the other Central.

So you will need some kind of communication between the 2 Centrals ...

[quote userid="75383" url="~/f/nordic-q-a/52972/connect-to-closest-central"]My idea involves role switching[/quote]

Does it - why ?