Bluetooth: Mesh Light Switch

The Bluetooth Mesh Light Switch sample demonstrates how to set up a basic Mesh client model application and control LEDs with the Bluetooth Mesh, using the Generic OnOff models.


This sample is split into two source files:

  • A main.c file to handle initialization.

  • One additional file for handling Mesh models, model_handler.c.


Provisioning is handled by the Bluetooth Mesh provisioning handler for Nordic DKs.


The following table shows the Mesh light composition data for this sample:

Element 1

Element 2

Element 3

Element 4

Config Server

Gen. OnOff Client

Gen. OnOff Client

Gen. OnOff Client

Health Server

Gen. OnOff Client

The models are used for the following purposes:

  • Generic OnOff Client instances in elements 1 to 4 are controlled by the buttons on the development kit.

  • 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.

The model handling is implemented in src/model_handler.c, which uses the DK Button and LED library to detect button presses on the board.

If the model is configured to publish to a unicast address, the model handler calls bt_mesh_onoff_cli_set() to turn the LEDs of a Mesh Light device on or off. The response from the target device updates the corresponding LED on the Mesh Light Switch device. If the model is configured to publish to a group address, it calls bt_mesh_onoff_cli_set_unack() instead, to avoid getting responses from multiple devices at once.


  • One of the following development boards:

    • nRF52840 Development Kit board (PCA10056)

    • nRF52 Development Kit board (PCA10040)

    • nRF51 Development Kit board (PCA10028)

  • Smartphone with Nordic Semiconductor’s nRF Mesh mobile app installed in one of the following versions:

  • Bluetooth: Mesh Light sample application programmed on a separate device and configured according to the Mesh Light sample’s Testing guide.

User interface


Buttons are used to control the respective Generic OnOff Clients. When pressed, the button toggles the LED state on a Mesh Light device.


Show the last known OnOff state of the targeted Bluetooth: Mesh Light board.

Building and running

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

See Building and programming a sample application for information about how to build and program the application.



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

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

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 Light Switch device to connect to it.

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

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

Once the provisioning and initial configuration is complete, the app will go back to the Network screen.

Configuring models

Complete the following steps in the nRF Mesh app to configure models:

  1. On the Network screen, tap the Mesh Light Switch node. Basic information about the mesh node and its configuration is displayed.

  2. In the Mesh node view, expand the first element. It contains the list of models in the first element of the node.

  3. Tap Generic OnOff Client to see the model’s configuration.

  4. Bind the model to application keys to make it open for communication:

    1. Tap BIND KEY at the top of the screen.

    2. Select Application Key 1 from the list.

  5. Configure the Client model publish parameters, which define how the model will send its messages:


    2. Set the Publish Address to the first unicast address of the Mesh Light node.

    3. Set the Retransmit Count to zero (Disabled) to prevent the model from sending each button press multiple times.

    4. Leave the rest of the publish parameters at their default values.

    5. Tap APPLY to confirm the configuration.

You are now be able to control the first LED on the Mesh Light device by pressing Button 1 on the Mesh Light Switch development kit.

Repeat steps 3-5 for each of the elements on the node to control each of the remaining three LEDs on the Mesh Light device.


This sample uses the following nRF Connect SDK libraries:

In addition, it uses the following Zephyr libraries: