Image Transfer Demo: ble_srv_is_notification_enabled flag not set

RE: Image Transfer Demo: ble_srv_is_notification_enabled flag not set

AlexW — Thu, 25 Jul 2019 13:29:43 GMT

Thanks. It works.

The thing acctually was that the image_transfer service has a third "image_info_send" characteristic which is obviously not implemented in the BLE_NUS service. The RX and TX Characteristics of the BLE_ITS and BLE_NUS Service have the same UUID.
That is why part of my transfer worked, but the image size info couldn't be sent.

And yes, I modified the image transfer demo already in a way that I do not need all those controlling messages.

THANK YOU!!

RE: Image Transfer Demo: ble_srv_is_notification_enabled flag not set

Edvin — Thu, 25 Jul 2019 12:09:08 GMT

Ok. Use nRF Connect for Desktop to see what services and Characteristic UUIDs you need to use. If I remember correctly, on the mobile application you need to select whether to take a photo or to send a stream, as well as selecting the picture quality. This means that there probably is a characteristic that you need to use to send messages to the nRF telling it to either send a picture or stream, and select the quality.

RE: Image Transfer Demo: ble_srv_is_notification_enabled flag not set

AlexW — Thu, 25 Jul 2019 11:10:12 GMT

OK, thanks.

Yes, I have two nrf52840.
One is running the Image tragsfer demo (slightly modified).
The other one is running the BLE NUS central example.

I established a connection between both boards already by adapting the target BASE_UUID on the central board.
So, now I will try to modify the ble_nus_c service in a way that it connects to the ble_its service on the peripheral board.

Finally, I want to transfer the image stream from the image_transfer_demo board to the other board, yes.

RE: Image Transfer Demo: ble_srv_is_notification_enabled flag not set

Edvin — Thu, 25 Jul 2019 09:34:27 GMT

No. The ble_its service and ble_nus service has different IDs (called UUID), so they do not work together.

I don't know what you are trying to do, but if you want to transfer data from one device (peripheral) to another (central), I suggest that you look into the ble_app_uart and ble_app_uart_c examples.

If you want to transfer data through the ble_its service, you need to create the ble_its_c (c for central). It will probably look a lot like the ble_nus_c, but with a different UUID for the service and the characteristics.

The ble_nus service has two characteristics, while I bet the ble_its service only has one.

If you have 2 DKs, I suggest that you program one with the ble_its example, and use the other to connect to it with nRF Connect for Desktop. This way, you can see what services and characteristics the device has. If the UUID is not shown automatically (not a familiar service) hovering the mouse over the name of the service will tell you the UUID.

Best regards,

Edvin

RE: Image Transfer Demo: ble_srv_is_notification_enabled flag not set

AlexW — Thu, 25 Jul 2019 08:11:17 GMT

Ahh ok, thanks.
I wasn't really into BLE services yet....

So that means, currently I have the ble_nus service on my BLE central board
and the ble_its service on my BLE peripheral board.
Do I have to implement the ble_its service on my central board instead of the ble_nus service? Or is it possible that the TX_characteristic of the ble_nus service receives the notifications of the ble_its service? And thus, I need to configure that the ble_its notifies the ble_nus TX_characteristic?

What will be the more useful option?

RE: Image Transfer Demo: ble_srv_is_notification_enabled flag not set

Edvin — Wed, 24 Jul 2019 14:19:52 GMT

I recommend you to read through this tutorial, if you are new to BLE centrals:

https://devzone.nordicsemi.com/nordic/short-range-guides/b/bluetooth-low-energy/posts/ble-central-tutorial

RE: Image Transfer Demo: ble_srv_is_notification_enabled flag not set

Edvin — Wed, 24 Jul 2019 14:18:43 GMT

Hello,

The image transfer demo has something called a service, with the image transfer demo (its) that it uses to send data through notifications. However, a peripheral can't send notifications unless the central has enabled notifications on that service.

In the ble_app_uart_c example, which uses the ble_nus_c service is actually a service that handles the ble_nus service which is used in the ble_app_uart example. If you look in the main.c file and ble_nus_c.c file in the ble_app_uart_c example, you can see how it enables notifications on the ble_nus TX characteristic. You have to adapt this to enable notifications on the hts characteristic instead.