Changing the representation of the BLE characteristic data

[morpho]

Is there a way to convert the data representation of the BLE characteristic into, say, strings?

Secondly, any way to debug as to why am I seeing more bytes than what i'm sending from my application? I am sending 6 bytes so 0x74-3D-31-31-32-43 and the rest isn't meaningful. 

Lastly, any way to set the service name? currently it says Unknown. Perhaps it would remain Unknown until the UUID is recognized by the central?

[Einar Thorsrud]

Hi,

There is no data transported over the air that indicate the type of data or name of services or characteristics. For that to be known (and displays), the GATT client implementation (for instance a mobile app) must know this beforehand.

[morpho]

1. GATT client would only know if it's a known BLE service based on the UUID?

2. What about modifying data representation in the mobile app itself?

[Einar Thorsrud]

morpho said:

1. GATT client would only know if it's a known BLE service based on the UUID?

Yes, that is correct.

morpho said:

2. What about modifying data representation in the mobile app itself?

Yes, that can be done. That is up to the app developer.

[morpho]

1. And if we were to create our own UUID to GAT client recognizes it, what'd be the procedure?

Einar Thorsrud said:

Yes, that can be done. That is up to the app developer

How though? I'm sending char bytes and it's showing as hexa as you can see in the screenshot above

[Einar Thorsrud]

morpho said:

1. And if we were to create our own UUID to GAT client recognizes it, what'd be the procedure?

As you write create your own UUID, that means make your own custom service. In this case it seems the server is on the nRF, so this tutorial would explain the nRF side of it. For the client on a mobile, you would need to implement your app so that it knows the mapping between the UUID and service and characteristics. This is typically something you always need to do for your Bluetooth apps.

morpho said:

How though? I'm sending char bytes and it's showing as hexa as you can see in the screenshot above

The screenshot is from nRF Connect, which is a mobile app made by us. It only includes names for services and characteristics that we included. You can use others based on UUID for testing though, but in order to see names etc. you will need your own iOS/Android app that you must develop yourself.