Bluetooth Mesh - Send customize data/command to node

[chunjie]

Is nRF Mesh app support feature that send customize data/command to node? The goal is to transmit data from phone to node, where it will be processed and used to trigger actions. Besides that, how to check what’s the roles of node currently running? Those fields are shown unknown in nRF Mesh app features section (Refer to attachment). Is it check from prj.conf file?

SDK version: v2.6.1
nRF Mesh app (IOS): 4.2.0
Hardware: nRF5340-DK

[AHaug]

Hi,

Is nRF Mesh app support feature that send customize data/command to node?

This discussion talks about how you can send customized vendor messages to a node:  How to Send messages from nrf mesh app to nrf52840? 

Besides that, how to check what’s the roles of node currently running?

As far as I know you will have to configure this through the prj.conf as suggested here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/protocols/bt/bt_mesh/configuring.html Do you see the node features in the app if you enable the node roles?

Kind regards,
Andreas

[chunjie]

Hi Andreas,

AHaug said:

This discussion talks about how you can send customized vendor messages to a node:  How to Send messages from nrf mesh app to nrf52840? 

I have gone through the post you shared. May I know how to use the access_model_publish() function and where can I find the API documentation for this? Besides, Edvin mentioned that there should be a field that says "Controls", where you can enter an Opcode and parameters. I flashed my board with Chat sample and configured the Control field in the nRF Mesh app. Nothing is shown in the terminal after I clicked send. Can you provide me some guidance on how to use this feature. My configuration of control field is as image below:

AHaug said:

As far as I know you will have to configure this through the prj.conf as suggested here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/protocols/bt/bt_mesh/configuring.html Do you see the node features in the app if you enable the node roles?

Yes I have configured Bluetooth Mesh configuration through proj.conf but the node features still unable to show in app. My configuration is as below:

# Bluetooth Mesh configuration

CONFIG_BT_MESH=y

CONFIG_BT_MESH_RELAY=y

CONFIG_BT_MESH_FRIEND=y

CONFIG_BT_MESH_TX_SEG_MAX=10

CONFIG_BT_MESH_PB_GATT=y

CONFIG_BT_MESH_GATT_PROXY=y

CONFIG_BT_MESH_PROXY_USE_DEVICE_NAME=y

CONFIG_BT_MESH_DK_PROV=y

 

[AHaug]

Hi,

chunjie said:

ay I know how to use the access_model_publish() function and where can I find the API documentation for this?

access_model_publish() is specifically for the nRF5 for mesh SDK so it won't be relevant for your application. I were referring to the other discussion more in terms of how to use the application to send vendor models, but I see that it might be misleading to refer to the other discussion as a whole. In general the Bluetooth Mesh API can be found here https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/connectivity/bluetooth/api/index.html#bluetooth-mesh 

chunjie said:

configured the Control field in the nRF Mesh app

By this do you refer to the steps in https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/mesh/chat/sample_description.html#configuring-models?

chunjie said:

Yes I have configured Bluetooth Mesh configuration through proj.conf but the node features still unable to show in app. My configuration is as below:

Allright, thank you for verifying.

I will discuss this with the developers further before the weekend

Kind regards,
Andreas

[chunjie]

Hi,

AHaug said:

By this do you refer to the steps in https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/mesh/chat/sample_description.html#configuring-models?

Yes, I have read through the doc and played with the sample. But the doc do not provide steps to configure the Control field.

[AHaug]

Hi,

I had a chat with the developers regarding the Features field you highlighted in the nRF Mesh app:

To see what features a node supports you will need to go to Element 1 / Config Server model and then Pull to refresh to read the states of each of the features for that nodes. For Android it looks to be automatically fetched after provisioning, while for iOS you need to read them manually. The app only reads Default TTL and the Composition Data when it enters that screen for the first time (or when they were not read before).

Kind regards,
Andreas

[chunjie]

Hi,

Unable to pull down.


Other than that, how does the message structure of Bluetooth mesh look like? From what I know, it contains 1-3 bytes opcode. What is the full message sent to node when we tap ON in GenericOnOff Server?

[AHaug]

Hi,

chunjie said:

Other than that, how does the message structure of Bluetooth mesh look like? From what I know, it contains 1-3 bytes opcode. What is the full message sent to node when we tap ON in GenericOnOff Server?

This is defined in the specification for Bluetooth Mesh, please download it for free here: https://www.bluetooth.com/specifications/specs/?types=specs-docs&keyword=mesh&filter= . Here you will find how various Mesh messages are defined.

Here's a general explanation of how messaging works from our documentation:

API: for Bluetooth Mesh messaging- https://docs.nordicsemi.com/bundle/ncs-latest/page/zephyr/connectivity/bluetooth/api/mesh/msg.html 

From Bluetooth Mesh Network Data flow - https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/protocols/bt/bt_mesh/architecture.html#bluetooth_mesh_network_data_flow 

Bluetooth Mesh uses Bluetooth Low Energy as a bearer or transport for its messages. The messages are encapsulated in either Bluetooth LE advertisements or GATT packets, referred to as advertising bearer or GATT bearer. The Bluetooth Mesh message provides a set of structures, macros, and functions used for preparing message buffers, managing message, and acknowledged message contexts.

In a typical data flow within a mesh network, the process begins when an application calls a model’s publish function. The model includes a message in a publishing packet with an opcode and sends it to the access layer. The access layer fetches the necessary publish parameters, like destination address, encryption keys, and time to live value (TTL value), and passes the packet to the transport layer. The transport layer then encrypts the message with the selected application key, and splits the message into segments if necessary. Each segment is passed to the network layer, which attaches a network header with a sequence number and encrypts the packet with the network key before passing it to the Bluetooth LE Controller. The Bluetooth LE Controller includes the network message in an advertisement packet, and schedules a time slot for the packet to be broadcasted.

From Bluetooth Mesh Concepts - https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/protocols/bt/bt_mesh/concepts.html#network_topology_and_relaying 

Bluetooth Mesh is a broadcast-based network protocol, where every device in the network sends and receives all messages to and from all devices within radio range. The advertisement packets are picked up by nearby mesh devices and handled like other Bluetooth LE advertisement packets. The mesh packets are represented with a unique AD (advertisement data) type and added to the advertisement packet payload.

Kind regards,
Andreas