Connect to closest Central

[ran]

Hi, 

Let's say I have 2 nrf52 Centrals in a room , now - I'm adding a peripheral and I'd like it to connect to the central with the better RSSI ( out of the 2 ) 

My idea involves role switching and seems pretty complicated. 

Thanks, 

Ran 

[awneil]

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 ...

ran said:

My idea involves role switching

Does it - why ?

[awneil]

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.

[ran]

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 . 

[awneil]

ran said:

"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

Not necessarily.

You might have non-BLE comms between them.

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

ran said:

roll switching

* role

[ran]

I guess I can try this

Peripheral-Central RSSI

[awneil]

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.

[ran]

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 :) 

[awneil]

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.