Matter: Light bulb

This light bulb sample demonstrates the usage of the Matter (formerly Project Connected Home over IP, Project CHIP) application layer to build a white dimmable light bulb device. This device works as a Matter accessory device, meaning it can be paired and controlled remotely over a Matter network built on top of a low-power, 802.15.4 Thread network. You can use this sample as a reference for creating your own application.

Note

This sample is self-contained and can be tested on its own. However, it is required when testing the Matter light switch sample.

Requirements

The sample supports the following development kits:

Hardware platforms

PCA

Board name

Build target

nRF52840 DK

PCA10056

nrf52840dk_nrf52840

nrf52840dk_nrf52840

nRF5340 DK

PCA10095

nrf5340dk_nrf5340

nrf5340dk_nrf5340_cpuapp

nRF21540 DK

PCA10112

nrf21540dk_nrf52840

nrf21540dk_nrf52840

For remote testing scenarios, you also need the following:

  • If you want to commission the light bulb device and control it remotely through a Thread network: a Matter controller device configured on PC or smartphone (which requires additional hardware depending on which setup you choose).

  • If you want to use the test mode and control the light bulb using light switch, the Matter light switch sample programmed to another supported development kit.

Note

Matter requires the GN tool. If you are updating from the nRF Connect SDK version earlier than v1.5.0, see the GN installation instructions.

Overview

The sample uses buttons to test changing the light bulb and device states, and LEDs to show the state of these changes. It can be tested in the following ways:

  • Standalone, by using a single DK that runs the light bulb application.

  • Remotely over the Thread protocol, which requires more devices.

The remote control testing requires a Matter controller, which can be configured either on PC or mobile (for remote testing in a network) or on an embedded device (for remote testing using test mode). Both methods can be enabled after building and running the sample.

Remote testing in a network

By default, the Matter accessory device has Thread disabled. You must pair it with the Matter controller over Bluetooth® LE to get configuration from the controller if you want to use the device within a Thread network. To do this, the device must be made discoverable manually (for security reasons) and the controller must get the commissioning information from the Matter accessory device and provision the device into the network. For details, see the Commissioning the device section.

Remote testing using test mode

Alternatively to the commissioning procedure, you can use the test mode, which allows to join a Thread network with default static parameters and static cryptographic keys. Use Button 3 to enable this mode after building and running the sample.

Note

The test mode is not compliant with Matter and it only works together with Matter controller and other devices which use the same default configuration.

Using the test mode allows you to control the light bulb remotely without using a smartphone compatible with Android. The light bulb device programmed with this sample can be used with the light switch device programmed with the Matter light switch sample to create a simplified Thread network.

Configuration

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

The sample uses different configuration files depending on the supported features. The configuration files are automatically attached to the build based on the build type suffix of the file name, such as _single_image_dfu in the prj_single_image_dfu.conf file. To modify configuration options, apply the modifications to the files with the appropriate suffix. See the table below for information about available configuration types:

Config suffix

Enabled feature

Enabling build option

Supported boards

none

none (basic build)

none

nrf52840dk_nrf52840 nrf5340dk_nrf5340_cpuapp

_single_image_dfu

Single-image Device Firmware Upgrade

-DBUILD_WITH_DFU=1

nrf52840dk_nrf52840

_multi_image_dfu

Multi-image Device Firmware Upgrade

-DBUILD_WITH_DFU=1

nrf5340dk_nrf5340_cpuapp

Device Firmware Upgrade support

Note

Over-the-air Device Firmware Upgrade can be enabled only on hardware platforms containing external flash memory.

You can configure the sample to use the secure bootloader for performing over-the-air Device Firmware Upgrade using Bluetooth® LE, using the -DBUILD_WITH_DFU=1 build flag during the build process.

See Providing CMake options for instructions on how to add these options to your build.

For example, when building on the command line, you can run the following command with build_target replaced with the build target name of the hardware platform you are using (see Requirements):

west build -b build_target -- -DBUILD_WITH_DFU=1

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 Radio front-end module (FEM) support 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.

User interface

LED 1:

Shows the overall state of the device and its connectivity. The following states are possible:

  • Short Flash On (50 ms on/950 ms off) - The device is in the unprovisioned (unpaired) state and is waiting for a commissioning application to connect.

  • Rapid Even Flashing (100 ms on/100 ms off) - The device is in the unprovisioned state and a commissioning application is connected through Bluetooth LE.

  • Solid On - The device is fully provisioned.

LED 2:

Shows the state of the light bulb. The following states are possible:

  • Solid On - The light bulb is on.

  • Off - The light bulb is off.

Button 1:

Depending on how long you press the button:

  • If pressed for 6 seconds, it initiates the factory reset of the device. Releasing the button within the 6-second window cancels the factory reset procedure.

  • If pressed for less than 3 seconds, it initiates the OTA software update process. The OTA process is disabled by default, but you can enable it when you build the sample with the DFU support (see Configuration).

Button 2:

Changes the light bulb state to the opposite one.

Button 3:

Starts the Thread networking in the test mode using the default configuration.

When running application in light switch test mode it also starts publishing the light bulb service messages for a predefined period of time to advertise the light bulb device IP address to the light switch device (if used). If for some reason the light switch device is not able to receive messages during this predefined period of time, you can restart publishing service by pressing this button again.

Button 4:

Starts the NFC tag emulation, enables Bluetooth® LE advertising for the predefined period of time (15 minutes by default), and makes the device discoverable over Bluetooth LE. This button is used during the commissioning procedure.

SEGGER J-Link USB port:

Used for getting logs from the device or for communicating with it through the command-line interface.

NFC port with antenna attached:

Optionally used for obtaining the commissioning information from the Matter accessory device to start the commissioning procedure.

Building and running

This sample can be found under samples/matter/light_bulb in the nRF Connect SDK folder structure.

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

See Configuration for information about building the sample with the DFU support.

Testing

You can either test the sample’s basic features or use the light switch sample to test the light bulb’s communication with another device.

Testing basic features

After building the sample and programming it to your development kit, test its basic features by completing the following steps:

  1. Connect the kit to the computer using a USB cable. The kit is assigned a COM port (Windows) or ttyACM device (Linux), which is visible in the Device Manager.

  2. Connect to the kit with a terminal emulator (for example, PuTTY). See How to connect with PuTTY for the required settings.

  3. Observe that LED 2 is off.

  4. Press Button 2 on the light bulb device. The LED 2 turns on and the following messages appear on the console:

    I: Turn On Action has been initiated
    I: Turn On Action has been completed
    
  5. Press Button 2 again. The LED 2 turns off and the following messages appear on the console:

    I: Turn Off Action has been initiated
    I: Turn Off Action has been completed
    
  6. Press Button 1 to initiate the factory reset of the device.

Testing communication with another device

After building this sample and the Matter light switch sample and programming them to development kits, test communication between both devices by completing the following steps:

  1. Complete the following actions for both devices:

    1. Connect the kit to the computer using a USB cable. The kit is assigned a COM port (Windows) or ttyACM device (Linux), which is visible in the Device Manager.

    2. Connect to the kit with a terminal emulator (for example, PuTTY). See How to connect with PuTTY for the required settings.

  2. On both devices, press Button 1 to reset them to factory settings.

  3. Pair both devices by completing the following steps:

    1. On the light switch device, press Button 3 to enable pairing on this device. The light switch becomes the Thread network Leader. The following messages appear in the console for the light switch device:

      I: Device is not commissioned to a Thread network. Starting with the default configuration
      I: Starting light bulb discovery
      
    2. On the light bulb device, press Button 3 to enable pairing on this device. The following messages appear on the console for the light bulb device:

      I: Device is not commissioned to a Thread network. Starting with the default configuration
      I: Started Publish service
      

      At this point, the light bulb is discovered by the light switch device and the following messages appear on the console for the light switch device:

      I: Stopping light bulb discovery
      I: Pairing with light bulb fdde:ad00:beef:0:7b0:750e:6d96:49e9
      
  4. On the light switch device, press Button 2 to turn off the light on the light bulb device. The following message appears on the console for the light switch device:

    I: Toggling the light
    

    LED 2 on the light bulb device turns off.

  5. On the light switch device, press Button 2 to turn on the light again. LED 2 on the light bulb device turns back on.

  6. On the light switch device, press Button 4 and hold it for a few seconds. Messages similar to the following one appear in the console:

    I: Setting brightness level to 7
    

    The brightness of LED 2 on the light bulb device changes while the button is pressed.

Enabling remote control

Remote control allows you to control the Matter light bulb device from a Thread network.

You can use one of the following options to enable this option:

  • Commissioning the device, which allows you to set up testing environment and remotely control the sample over a Matter-enabled Thread network.

  • Remote testing using test mode, which allows you to test the sample functionalities in a Thread network with default parameters, without commissioning. Use Button 3 to enable this mode after building and running the sample.

Commissioning the device

To commission the device, go to the Configuring Matter development environment page and complete the steps for the Matter controller you want to use. As part of this tutorial, you will configure Thread Border Router, build and install the Matter controller, commission the device, and send Matter commands that cover scenarios described in the Testing section. If you are new to Matter, the recommended approach is Configuring Thread Border Router and mobile Matter Controller using an Android smartphone.

Before starting the commissioning procedure, the device must be made discoverable over Bluetooth LE, which starts automatically upon the device startup, but only for a predefined period of time (15 minutes by default). If the Bluetooth LE advertising times out, you can re-enable it by pressing Button 4.

When you start the commissioning procedure, the controller must get the commissioning information from the Matter accessory device. The data payload, which includes the device discriminator and setup PIN code, is encoded within a QR code, printed to the UART console, and can be shared using an NFC tag.

Upgrading the device firmware

To upgrade the device firmware, complete the steps listed for the selected method in the Performing Device Firmware Upgrade in the nRF Connect examples tutorial in the Matter documentation.

Dependencies

This sample uses the Matter library, which includes the nRF Connect SDK platform integration layer:

In addition, the sample uses the following nRF Connect SDK components:

The sample depends on the following Zephyr libraries: