Looking for way to get central to match service UUID pattern

RE: Looking for way to get central to match service UUID pattern

Dan K. — Sat, 06 Feb 2016 20:24:20 GMT

We decided to go with using manufacturer data to relay the information, and keep the UUIDs constant. That seems to be the cleanest solution. Thanks to everyone for the suggestions.

RE: Looking for way to get central to match service UUID pattern

John — Thu, 04 Feb 2016 13:00:23 GMT

We went with the manufacturer data route. Adding it was very easy with the existing SDK support. It took far longer to get the SIG to create an id for us than to make the code changes.

RE: Looking for way to get central to match service UUID pattern

tesc — Thu, 04 Feb 2016 10:18:40 GMT

I would definately consider custom manufacturer data, or perhaps add the required information to service data. According to the latest BLE Core Specification Supplement the Service UUID in service data is optionally followed by additional service data. I have not looked into what exactly is the purpose of this additional data or if this is easily done through the SDK, though.

RE: Looking for way to get central to match service UUID pattern

Anders Strand — Thu, 04 Feb 2016 10:11:49 GMT

Advertising and scanning happens before connection, and service discovery happens after connection. You do not have to advertise the same UUID as you have in you gatt server (the one found in service discovery). You can advertise a custom uuid (with encoded data inside), and recognize this in you scanner handling. Alternatively you can put custom data in the manufacturer specific field in the advertisement.

RE: Looking for way to get central to match service UUID pattern

RK — Wed, 03 Feb 2016 23:16:24 GMT

Several options. Don't use the discovery manager, write your own discovery code directly using the softdevice events.

Alternatively the discovery manager code is pretty simple, start with it and modify it to discover all services and match the UUID you want instead of registering for exact service matches.

Or before you call the discovery manager code, do your own initial query of all the services on the device, handle the callbacks, find the service you want, then put its actual UUID in the discovery db and run it from there. Bit wasteful but not very.

.. adding another .. put the two bytes in some custom manufacturer data in the advertisement or scan response data so you know what the full service will be before you go discover it .. or don't even then bother to change the service uuid, just use the bytes you got during scanning

RE: Looking for way to get central to match service UUID pattern

Dan K. — Wed, 03 Feb 2016 23:06:52 GMT

Thanks for the response. The problem is that I'd like to get the encoded information without having to connect to the service.

RE: Looking for way to get central to match service UUID pattern

John — Wed, 03 Feb 2016 21:54:06 GMT

I have no idea if what you want to do is possible. But, what if instead of changing the service UUID, add a read only characteristic to the service with the information you want to encode instead?