Problem reading Ble characteristics on android

RE: Problem reading Ble characteristics on android

bjorn-spockeli — Fri, 21 Feb 2020 08:38:32 GMT

I do not think that splitting one service with 50 characteristics into two services with 25 characteristics each will solve the issue. I suspect that you will see issues with the second service, e.g. that the last 10 or so characteristics of the second service will be listed as descriptors of the 15th characteristic.

However I have not tested this, so I might be wrong. As mentioned by another user in the question you referred to, do you need 50 characteristics?

[quote user="JOK"][/quote]

BTW: it seems that this issue is solved in newer Android versions:

https://devzone.nordicsemi.com/f/nordic-q-a/48172/characteristics-count-limit-on-android

Yes, but you need to remember that most smartphone vendors adapt the Android OS so adding changes might take a long time.

RE: Problem reading Ble characteristics on android

JOK — Fri, 21 Feb 2020 07:59:00 GMT

Hi Bjørn,

Thanks for your answer, but I don't fully understand the issue. There is a limit of 40 chars defined in Android. Is this a limit of 40 chars in a service or 40 chars in total in all services.

In the first case I should split the service into multiple smaller services. If the second case is true, I probably have a problem ;-) Any ideas on this?

BTW: it seems that this issue is solved in newer Android versions:

https://devzone.nordicsemi.com/f/nordic-q-a/48172/characteristics-count-limit-on-android

RE: Problem reading Ble characteristics on android

bjorn-spockeli — Thu, 20 Feb 2020 14:04:15 GMT

Hi JOK,

Yes, there seems to be a limit on the number of characteristics that an Android device can discover during service discovery, see https://stackoverflow.com/questions/24531334/is-there-any-limit-on-characteristics-uuid-in-android-ble and https://issuetracker.google.com/issues/37005408.

Best regards

Bjørn