Matter: Light bulb

Requirements
Overview
- Remote testing in a network
Configuration
User interface
Building and running
Dependencies

This light bulb sample demonstrates the usage of the Matter 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
nRF5340 DK	PCA10095	nrf5340dk_nrf5340	`nrf5340dk_nrf5340_cpuapp`
nRF52840 DK	PCA10056	nrf52840dk_nrf52840	`nrf52840dk_nrf52840`
nRF21540 DK	PCA10112	nrf21540dk_nrf52840	`nrf21540dk_nrf52840`

If you want to commission the light bulb device and control it remotely through a Thread network, you also need a Matter controller device configured on PC or mobile. This requires additional hardware depending on the setup you choose.

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. You can test it 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 that you can configure either on a PC or a mobile device (for remote testing in a network). You can enable both methods 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 the configuration from the controller to use the device within a Thread network. 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.

Configuration 

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

Matter light bulb build types 

The sample uses different configuration files depending on the supported features. Configuration files are provided for different build types and they are located in the application root directory.

The prj.conf file represents a debug build type. Other build types are covered by dedicated files with the build type added as a suffix to the prj part, as per the following list. For example, the release build type file name is prj_release.conf. If a board has other configuration files, for example associated with partition layout or child image configuration, these follow the same pattern.

When the CONF_FILE variable contains a single file and this file follows the naming pattern prj_<buildtype>.conf, then the build type will be inferred to be <buildtype>. The build type cannot be set explicitly. The <buildtype> can be any string, but it is common to use release and debug.

For information about how to set variables, see Important Build System Variables in the Zephyr documentation.

The Partition Manager’s static configuration can also be made dependent on the build type. When the build type has been inferred, the file pm_static_<buildtype>.yml will have precedence over pm_static.yml.

The child image Kconfig configuration can also be made dependent on the build type. The child image Kconfig file is named <child_image>.conf instead of prj.conf, but otherwise follows the same pattern as the parent Kconfig.

Before you start testing the application, you can select one of the build types supported by the sample. This sample supports the following build types, depending on the selected board:

debug – Debug version of the application - can be used to enable additional features for verifying the application behavior, such as logs or command-line shell.
release – Release version of the application - can be used to enable only the necessary application functionalities to optimize its performance.
no_dfu – Debug version of the application without Device Firmware Upgrade feature support - can be used for the nRF52840 DK, nRF5340 DK, and nRF21540 DK.

Note

Selecting a build type is optional. The debug build type is used by default if no build type is explicitly selected.

Device Firmware Upgrade support 

Note

You can enable over-the-air Device Firmware Upgrade only on hardware platforms that have external flash memory. Currently only nRF52840 DK and nRF5340 DK support Device Firmware Upgrade feature.

The sample supports over-the-air (OTA) device firmware upgrade (DFU) using one of the two following protocols:

Matter OTA update protocol that uses the Matter operational network for querying and downloading a new firmware image.
Simple Management Protocol (SMP) over Bluetooth® LE. In this case, the DFU can be done either using a smartphone application or a PC command line tool. Note that this protocol is not part of the Matter specification.

In both cases, MCUboot secure bootloader is used to apply the new firmware image.

The DFU over Matter is enabled by default. The following configuration arguments are available during the build process for configuring DFU:

To configure the sample to support the DFU over Matter and SMP, use the -DCONFIG_CHIP_DFU_OVER_BT_SMP=y build flag.
To configure the sample to disable the DFU and the secure bootloader, use the -DCONF_FILE=prj_no_dfu.conf build flag.

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

When building on the command line, run the following command with build_target replaced with the build target name of the hardware platform you are using (see Requirements), and dfu_build_flag replaced with the desired DFU build flag:

west build -b build_target -- dfu_build_flag

For example:

west build -b nrf52840dk_nrf52840 -- -DCONFIG_CHIP_DFU_OVER_BT_SMP=y

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.

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 over 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 less than three seconds, it initiates the SMP server (Security Manager Protocol). After that, the Direct Firmware Update (DFU) over Bluetooth Low Energy can be started. (See Upgrading the device firmware.)
If pressed for more than three seconds, it initiates the factory reset of the device. Releasing the button within the 3-second window cancels the factory reset procedure.

Button 2:: Changes the light bulb state to the opposite one.
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.

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.

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

Selecting a build type 

Before you start testing the application, you can select one of the Matter light bulb build types, depending on your building method.

Selecting a build type in Visual Studio Code

To select the build type in the nRF Connect for VS Code extension:

When Building an application as described in the nRF Connect for VS Code extension documentation, follow the steps for setting up the build configuration.
In the Add Build Configuration screen, select the desired .conf file from the Configuration drop-down menu.
Fill in other configuration options, if applicable, and click Build Configuration.

Selecting a build type from command line

To select the build type when building the application from command line, specify the build type by adding the following parameter to the west build command:

-- -DCONF_FILE=prj_selected_build_type.conf

For example, you can replace the selected_build_type variable to build the release firmware for nrf52840dk_nrf52840 by running the following command in the project directory:

west build -b nrf52840dk_nrf52840 -d build_nrf52840dk_nrf52840 -- -DCONF_FILE=prj_release.conf

The build_nrf52840dk_nrf52840 parameter specifies the output directory for the build files.

Note

If the selected board does not support the selected build type, the build is interrupted. For example, if the shell build type is not supported by the selected board, the following notification appears:

File not found: ./ncs/nrf/samples/matter/light_bulb/configuration/nrf52840dk_nrf52840/prj_shell.conf

Testing 

After building the sample and programming it to your development kit, complete the following steps to test its basic features.

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, complete the following steps to test its basic features:

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.
Connect to the kit with a terminal emulator that supports VT100/ANSI escape characters (for example, PuTTY). See How to connect with PuTTY for the required settings.
Observe that LED 2 is off.
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
```
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
```
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 the development kits, complete the steps in the following sections to test communication between both devices.

Bind both devices

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.
Connect to the kit with a terminal emulator that supports VT100/ANSI escape characters (for example, PuTTY). See How to connect with PuTTY for the required settings.
If devices were not erased during the programming, press and hold Button 1 on each device until the factory reset takes place.
On each device, press Button 4 to start the Bluetooth LE advertising.
Commission devices to the Matter network. See Commissioning the device for more information. During the commissioning process, write down the values for the light switch node ID and the light bulb node ID (or IDs, if you are using more than one light bulb). These IDs are going to be used in the next steps (<light_switch_node_ID> and <light_bulb_node_ID>, respectively).
Use the CHIP Tool (“Writing ACL to the accesscontrol cluster” section) to add proper ACL for the light bulb device. Depending on the number of the light bulb devices you are using, use one of the following commands, with <light_switch_node_ID> and <light_bulb_node_ID> values from the previous step about commissioning:
- If you are using only one light bulb device, run the following command for the light bulb device:
```
chip-tool accesscontrol write acl '[{"fabricIndex": 1, "privilege": 5, "authMode": 2, "subjects": [112233], "targets": null}, {"fabricIndex": 1, "privilege": 3, "authMode": 2, "subjects": [<light_switch_node_ID>], "targets": [{"cluster": 6, "endpoint": 1, "deviceType": null}, {"cluster": 8, "endpoint": 1, "deviceType": null}]}]' <light_bulb_node_ID> 0
```
- If you are using more than one light bulb device, connect all devices to the multicast group by running the following command for each device, including the light switch:
```
chip-tool tests TestGroupDemoConfig --nodeId <node_ID>
```
  Use the <node_ID> values from the commissioning step.

Write a binding table to the light switch to inform the device about all endpoints by running this command (only for light switch):

For unicast binding to bind the light switch with only one light Bulb:

chip-tool binding write binding '[{"fabricIndex": 1, "node": <light bulb node id>, "endpoint": 1, "cluster": 6}, {"fabricIndex": 1, "node": <light bulb node id>, "endpoint": 1, "cluster": 8}]' <light switch node id> 1

For groupcast binding to bind the light switch with multiple light bulbs:

chip-tool binding write binding '[{"fabricIndex": 1, "group": 257}]' <light_switch_node_ID> 1

Test connection

After preparing devices for testing, you can test the communication of a single light bulb or a group of light bulbs with the light switch, but not both a single device and a group at the same time.

Complete the following steps:

On the light switch device, use buttons to control the bound light bulbs:
1. On the light switch device, press Button 2 to turn off the LED 2 located on the bound light bulb device.
2. On the light switch device, press Button 2 to turn on the light again. LED 2 on the light bulb device turns back on.
3. Press Button 2 and hold it for more than 0.5 seconds to test the dimmer functionality. LED 2 on the bound light bulb device changes its brightness from 0% to 100% with 1% increments every 300 milliseconds as long as Button 2 is pressed.
Using the terminal emulator connected to the light switch, run the following Matter CLI commands:
1. Write the following command to turn on LED 2 located on the bound light bulb devices:
  - For a single bound light bulb:
    matter switch onoff on
  - For a group of light bulbs:
    matter switch groups onoff on
2. Write the following command to turn on LED 2 located on the bound light bulb device:
  - For a single bound light bulb:
    matter switch onoff off
  - For a group of light bulbs:
    matter switch groups onoff off

Enabling remote control 

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

Commissioning the device allows you to set up a testing environment and remotely control the sample over a Matter-enabled Thread or Wi-Fi network.

Commissioning the device

To commission the device, go to the Testing Matter in the nRF Connect SDK page and complete the steps for the Matter over Thread development environment and the Matter controller you want to use. After choosing the environment configuration, the guide walks you through the following steps:

Configure the Thread Border Router.
Build and install the Matter controller.
Commission the device.
Send Matter commands that cover scenarios described in the Testing section.

If you are new to Matter, the recommended approach is to use CHIP Tool for Linux or macOS.

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

When you start the commissioning procedure, the controller must get the commissioning information from the Matter accessory device. The data payload includes the device discriminator and setup PIN code. It 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 that includes the nRF Connect SDK platform integration layer:

Matter

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

The sample depends on the following Zephyr libraries: