S110 role switching

[cocoa]

Is possible to put S110 in observer role (as peripheral) , waiting for a specific advertising (or waiting for an active scanning) and then switch to advertiser role (always as peripheral) ?

Thank all.

Update : Nordic has released S130 softdevice.

[Ole Morten]

You're right that it won't hide the device completely, but since you have full control over the advertising data, you can choose to just not include any data at all if you already have a bond and are advertising with whitelist. This will let other devices see that there is some advertiser here, and possibly locate it by using RSSI measurements, but they will not be able to connect or to get any information from it.

The reason that switching would be complicated is that both of the devices will have to be dual-role, and both have to switch at the same time, so there have to be some channel for them to coordinate this switch. If we talk about a tag and a phone, it would have to work something like this:

1. The tag continuously scans for advertisement packets, as a Central.
2. The phone continuously sends out advertisement packets, as a Peripheral.
3. When the phone comes into range, the tag would most likely have to connect to the phone to tell it to switch roles.
4. The phone would then start scanning for the tag.
5. The tag would have to start advertising.
6. The phone can then connect and they can transmit data.

Without the role switching, it would instead work like this:

1. The tag is continuously advertising with whitelist.
2. Once the phone comes into range, it can connect and data transfer can start.

The major problem with the first solution, in addition to the complicity, is that scanning is a power-hungry operation as compared to advertising. It requires the radio to be on in RX mode for relatively long periods of time.

However, since the roles that affect data transfer (GATT Server and GATT Client) is unrelated to the roles of Peripheral/Central, and as such, with the first solution, it would be possible to stop at step 3 and exchange data. This could be an option, but the current consumption is still a problem.

[Ole Morten]

You would have to have some method to get the device to clear its existing Central, and be ready for a new one, for example a button press. But I'm not sure I see how this is any different for the dual-role-scenario.

If however you have more questions on this, I'd suggest that you create a support case, since that is more targeted towards this kind of discussion.

[cocoa]

Hi Ole,

any news about an implementation of Observer role in S110 ?

bye.

-c

[Ole Morten]

I'm afraid I can't comment on that, so you should get in touch with our sales managers to get information on upcoming features. If you don't have their contact information, send me a PM with your location.