Bluetooth: Mesh sensor observer

The Bluetooth® mesh sensor observer sample demonstrates how to set up a basic Bluetooth mesh Sensor Client model application that gets sensor data from one Sensor Server model. Four different sensor types are used to showcase different ways for the server to publish data. In addition, the samples demonstrate usage of both single-channel sensor types and sensor series types.

Note

This sample must be paired with Bluetooth: Mesh sensor to show any functionality. The observer has no sensor data, and is dependent on a mesh sensor to provide it.

Requirements

The sample supports the following development kits:

Hardware platforms	PCA	Board name	Build target
nRF52 DK	PCA10040	nrf52dk_nrf52832	nrf52dk_nrf52832
nRF52840 DK	PCA10056	nrf52840dk_nrf52840	nrf52840dk_nrf52840
nRF21540 DK	PCA10112	nrf21540dk_nrf52840	nrf21540dk_nrf52840

The sample also requires a smartphone with Nordic Semiconductor’s nRF Mesh mobile app installed in one of the following versions:

• nRF Mesh mobile app for Android

• nRF Mesh mobile app for iOS

Additionally, the sample requires the Bluetooth: Mesh sensor sample application, programmed on a separate development kit and configured according to mesh sensor sample’s testing guide.

Overview

The following Bluetooth mesh sensor types are used in this sample:

• bt_mesh_sensor_present_dev_op_temp - Published by the server according to its publishing period.

• bt_mesh_sensor_rel_runtime_in_a_dev_op_temp_range - Periodically requested by the client.

• bt_mesh_sensor_presence_detected - Published when a button is pressed on the server.

• bt_mesh_sensor_time_since_presence_detected - Periodically requested by the client and published by the server according to its publishing period.

Provisioning

The provisioning is handled by the Bluetooth mesh provisioning handler for Nordic DKs. It supports four types of out-of-band (OOB) authentication methods, and uses the Hardware Information driver to generate a deterministic UUID to uniquely represent the device.

Use nRF Mesh mobile app for provisioning and configuring of models supported by the sample.

Models

The following table shows the mesh sensor observer composition data for this sample:

Element 1
Config Server
Health Server
Sensor Client

The models are used for the following purposes:

• Config Server allows configurator devices to configure the node remotely.

• Health Server provides attention callbacks that are used during provisioning to call your attention to the device. These callbacks trigger blinking of the LEDs.

• Sensor Client gets sensor data from one or more Sensor Server(s).

The model handling is implemented in src/model_handler.c. A k_work_delayable item is submitted recursively to periodically request sensor data.

User interface

Buttons:

Can be used to input the OOB authentication value during provisioning. All buttons have the same functionality during the provisioning procedure.

Terminal:

All sensor values gathered from the server are printed over UART. For more details, see Testing and debugging an application.

Configuration

See Configuring your application for information about how to permanently or temporarily change the configuration.

Source file setup

This sample is split into the following source files:

• A main.c file to handle initialization.

• One additional file for handling Bluetooth mesh models, model_handler.c.

FEM support

You can add support for the nRF21540 front-end module to this sample by using one of the following options, depending on your hardware:

• Build the sample for one board that contains the nRF21540 FEM, such as nrf21540dk_nrf52840.

• Manually create a devicetree overlay file that describes how FEM is connected to the nRF5 SoC in your device. See Set devicetree overlays for different ways of adding the overlay file.

• Provide nRF21540 FEM capabilities by using a shield, for example the nRF21540 EK shield that is available in the nRF Connect SDK. In this case, build the project for a board connected to the shield you are using with an appropriate variable included in the build command. This variable instructs the build system to append the appropriate devicetree overlay file. For example, to build the sample from the command line for an nRF52833 DK with the nRF21540 EK attached, use the following command within the sample directory:

  west build -b nrf52833dk_nrf52833 -- -DSHIELD=nrf21540_ek
  

  This command builds the application firmware. See Programming nRF21540 EK for information about how to program when you are using a board with a network core, for example nRF5340 DK.

Each of these options adds the description of the nRF21540 FEM to the devicetree. See Working with RF front-end modules for more information about FEM in the nRF Connect SDK.

To add support for other front-end modules, add the respective devicetree file entries to the board devicetree file or the devicetree overlay file.

Building and running

This sample can be found under samples/bluetooth/mesh/sensor_client in the nRF Connect SDK folder structure.

To build the sample with Visual Studio Code, follow the steps listed on the Building nRF Connect SDK application quick guide page in the nRF Connect for VS Code extension documentation. See Building and programming an application for other building and programming scenarios and Testing and debugging an application for general information about testing and debugging in the nRF Connect SDK.

Testing

Note

The mesh sensor observer sample cannot demonstrate any functionality on its own, and needs a device with the Bluetooth: Mesh sensor sample running in the same mesh network. Before testing the mesh sensor observer, go through the mesh sensor’s testing guide with a different development kit.

After programming the sample to your development kit, you can test it by using a smartphone with nRF Mesh mobile app installed. Testing consists of provisioning the device and configuring it for communication with the mesh models.

All sensor values gathered from the server are printed over UART. For more details, see Testing and debugging an application.

Provisioning the device

The provisioning assigns an address range to the device, and adds it to the mesh network. Complete the following steps in the nRF Mesh app:

1. Tap Add node to start scanning for unprovisioned mesh devices.

2. Select the Mesh Sensor Observer device to connect to it.

3. Tap Identify, and then Provision, to provision the device.

4. When prompted, select an OOB method and follow the instructions in the app.

Once the provisioning is complete, the app returns to the Network screen.

Configuring models

See Configuring mesh models using the nRF Mesh mobile app for details on how to configure the mesh models with the nRF Mesh mobile app.

Configure the Sensor Client model on the Mesh Sensor Observer node:

• Bind the model to Application Key 1.

• Set the publication parameters:

  • Destination/publish address: Select an existing group or create a new one, but make sure that the Sensor Server subscribes to the same group.

  • Retransmit count: Set the count to zero (Disabled), to avoid duplicate logging in the UART terminal.

• Set the subscription parameters: Select an existing group or create a new one, but make sure that the Sensor Server publishes to the same group.

The Sensor Client model is now configured and able to receive data from the Sensor Server.

Dependencies

This sample uses the following nRF Connect SDK libraries:

• Sensor Client

• Bluetooth mesh provisioning handler for Nordic DKs

• DK Buttons and LEDs

In addition, it uses the following Zephyr libraries:

• include/drivers/hwinfo.h

• Kernel Services:

  • include/kernel.h

• Bluetooth APIs:

  • include/bluetooth/bluetooth.h

• Bluetooth Mesh Profile:

  • include/bluetooth/mesh.h