How to enforce connecting to a specific master when bonded to many.

[Francesco]

Problem:

In our project we have one peripheral which can be bonded to many phones at the same time (of cause) while they are still close to it, thus connected via OS.

In that situation we need to selectively unblock the peripheral so that only one phone can connect to the peripheral. Thus if there are other phones nearby which are also bonded and one of them even is connected already, we need to disconnect them fist to allow the connection to the intended phone?

The connection should only be forced in a specific moment, i.e. not disconnect the other phones (masters) permanently. What wuld be the most appropriate technical solution for this scenario?

We are using the Nrf51 with S310 (v3.0.0). Our peripheral has an color LED to indicate state and a physical button (only) which supports hold/press gestures.

Thanks in advance for your help!

[Petter Myhre]

As a peripheral it can only be connected to one central at the time, if it is connected to a central it has to disconnect from that central before another central can connect.

If you only want a specific central to connect you should advertise with a whitelist and put the address of the specific central into the whitelist.

[Francesco]

Thanks for the quick response. The issue with that approach is that all the other centrals are basically on the whitelist. In the scenario I mentioned originally we need to disconnect other connected centrals to enable a specific central to connect with the peripheral. Kind of a temporary kill-switch for the BT connection.

[Petter Myhre]

Why is that an issue? Just remove them from the whitelist. You can keep the bond to the other centrals even though they are not in the whitelist.

[Francesco]

So you mean a whitelist for active connections (i.e. who would see the peripheral when it advertises itself)?! Still in my scenario the peripheral would already be connected to a central device. Now another NEW central should get priority and the ability to steel the connection. I think a whitelist is not a solution here as we want to allow that new device to connect as well. Rather we need a solution to steel the connection from other connected centrals. The user which gets that priority is the one standing closest to the peripheral at that time. So we could identify that person via a hardware button he needs to press to take over the connection. Question though is what would be the appropriate technical solution.

[Francesco]

2 suggestions: 1) disconnect from all devices and hope the closest will take over the connection. That's very random I think. 2) Narrow down TX power on the peripheral for X seconds. But that may vary as well as we cannot influence the tx power of the centrals nearby. Both suggestions seem not very stable to me.