nRF5340_Audio with Hearing Aid DEMO

[JohnnyNuance]

I am attempting to set up a demonstration between nRF5340_Audio and hearing aids that support LE Audio with CODEC LC3.

I began the process with the nRF5340_Audio project using two boards, one as a Gateway and the other as a Headset (Left). After establishing a connection between the two devices, I disconnected them and attempted to connect the Gateway to the hearing aids. Although a connection was established, I was unable to hear any audio stream.

After disconnecting the Gateway from the hearing aids, I received the following message:

 

After several attempts and a conversation with a Nordic representative, I learned that this project does not currently support connectivity with devices other than nRF5340 Audio boards.

Another suggestion was, combining two samples from Nordic's SDK:

1) hap_ha which is adapted to a hearing aids protocol.

2) unicast_server which has CODEC LC3 configurations.

To begin, I flashed unicast_server into one board and unicast_client into the other. However, I received the following messages:

I would like to mention that I did not modify the code, and it was flashed as a standard sample of the Nordic SDK.

I have two questions:

1. Why does this standard example fail when I try to connect between the two devices? (First, I would like to connect the two boards, and afterward, I would like to connect one board to the hearing aids)

2. In the hap_ha sample, I see a mention of support for CODEC LC3, but I do not see any implementation for LC3 inside the code. Is it possible to configure LC3 inside the sample easily?

[dejans]

Hi,

Could you try using NCS v2.5.0? What is the result?

Which hearing aid device do you use? How do you disconnect devices before connecting to hearing aid device?

Unicast server and unicast client samples use softdevice controller which does not support ISO. Therefore, you would need to add the following lines to your prj.conf file,

CONFIG_NCS_INCLUDE_RPMSG_CHILD_IMAGE=n
CONFIG_BT_HCI_VS_EXT=n 

rebuild, and program audio controller hex file to the network core.

Best regards,
Dejan

[JohnnyNuance]

Hey Dejan, thank you for the reply,

1) I already used NCS v2.5.0, NCSv2.51 and v2.5.99. all with the same behavior. 

2) I'm using Starkey hearing aids supporting LC3, which is still in development. I was able to connect them with Google Pixel 7 Pro and hear the audio stream.

2) Before connecting to the hearing aid device, I pressed B5 and reset, which cleared all bonds.

3) Your instructions worked, now I see the boards are trying to connect, but I still don't hear an audio stream.

I made 3 setups:

a. 2 boards, one acts as a server, and the second acts as a client.

b. 1 board acts as a server and connects  to Google Pixel 7 Pro

c. 1 board acts as a client and connects to Starkey hearing aids

None of the setups I hear an audio stream

I took pictures of the logs:

Unicast Server - Unicast Client  

Unicast Server - Google Pixel 7 Pro

Unicast Client - Starkey HA

Please help me what to do next. Thank you so much.

[dejans]

Hi,

Regarding your initial problem with connection to the hearing-aid, I had a discussion with our developers. Here are their observations:
- gateway connects to the headsets
- before gateway finishes discovery, headset is turned off. VCS discovery has been finished, but PACS discovery has not yet been finished
- scanning and connecting to the hearing-aid fails
Once the gateway connects and bonds with headsets, gateway accepts only direct advertising from the bonded headset and it will not scan and connect to new device using ordinary ADV. You can refer to the relevant code here. There is a possibility to increase maximum number of paired devices in Kconfig.defaults.

Which audio controller version have you flashed to the network core for unicast_client and unicast_server?

Best regards,
Dejan

[ERAN GISSER]

Hi,

We flashed ble5-ctr-rpmsg_3424.hex on both unicast_client and unicast_server.

Regarding your remark about that the gateway accepts only direct advertising from the bonded headset and it will not scan and connect to new device , Pls note that we erase the connection between the gateway and headset before connecting the gateway to the hearing aid. it seems that there is a connection but codec capabilities is not valid.

Pls advice how to proceed.

Tnx,

Eran.

[dejans]

Hi Eran,

Thank you for additional information.

Regarding unicast_client sample, you could try to add CONFIG_BT_BUF_ACL_TX_COUNT=4 in its prj.conf to make it work without errors. However, as this is upstream Zephyr sample, it does not include any HW codec driver and infrastructure. Therefore, it is expected for users not to hear any sound.

Please let me know if you have any further questions.

Best regards,
Dejan