esp-matter/examples/esp-now_bridge_light

ESP-NOW Matter Bridge Light

This example demonstrates a Matter to ESP-NOW bridge that bridges an ESP-NOW switch device to Matter fabric. It integrates ESP-NOW into a Matter light device to create a ESP-NOW bridge light.

In the ESP-NOW part, it acts as a responder whereas a ESP-NOW switch is an initiator.

In the Matter part, it creates a Color Temperature Light device and an aggregator device using the ESP Matter data model. When binding with an ESP-NOW switch is complete, it also creates a dynamic OnOff Switch device that works like a normal Matter switch. When unbind from the ESP-NOW switch, the dynamic switch device is removed.

See the docs for more information about building and flashing the firmware.

1. Additional Environment Setup

• Use a DevKit with LED, for example ESP32-C3-DevKitM to get more status indication.
• Use the switch example in ESP-NOW repository as the ESP-NOW switch.
• Use the light example in this repository as the light device.

2. Post Commissioning Setup

Note: Matter Wi-Fi devices enters modem sleep after commissioning. This will impact the ESP-NOW operation as ESP-NOW low power is not yet integrated. A responder device cannot enter sleep mode in order to receive messages from an initiator any time. This is done by setting WIFI_PS_NONE. Reboot the bridge after commissioning to apply the setting and let the bridge exit sleep mode. When esp-matter is updated to work in IDFv5.0, this example will be updated to enable ESP-NOW low power. Then disabling sleep is not required. {.is-info}

2.1 Discovering bridge endpoint

You can read the parts list from the Bridge to get the number of the bridged devices.

descriptor read parts-list 0x7283 0x0

If binding with ESP-NOW switch is not done, you will get 2 entries 1 and 2. Example:

PartsList: 2 entries
  [1]: 1
  [2]: 2

You can read the device type list for each of the endpoints.

descriptor read device-type-list 0x7283 1
descriptor read device-type-list 0x7283 2

Endpoint 1:

DeviceTypeList: 1 entries
  [1]: {
    Type: 268 <-------------------- Color temperature light device type
    Revision: 2
   }

Endpoint 2:

DeviceTypeList: 1 entries
  [1]: {
    Type: 14 <-------------------- Aggregator device type
    Revision: 1
   }

2.x Bind bridge to a ESP-NOW switch

Trigger binding from the ESP-NOW switch. If you are using a C3 DevKit, double click the Boot button. If binding is successful, the LED on the DevKit running bridge example will toggle. A dynamic endpoint will be added on the Bridge device. You can read the parts list again to get the dynamic endpoint ID.

descriptor read parts-list 0x7283 0

There is a new endpoint added to the device. Example:

  PartsList: 3 entries
    [1]: 1
    [2]: 2
    [3]: 3

You can read the device type list for the new endpoint.

descriptor read device-type-list 0x7283 3

Endpoint 3:

DeviceTypeList: 2 entries
  [1]: {
    Type: 19 <-------------------- Bridged node device type
    Revision: 1
   }
  [2]: {
    Type: 259 <-------------------- ONOFF switch device type
    Revision: 2
   }

There are two device types in this endpoint: 19 (0x0013) is bridged node device type, and 259 (0x0103) is ONOFF switch device type. You can read the cluster servers and clients list on the dynamic endpoint.

descriptor read server-list 0x7283 3
descriptor read client-list 0x7283 3

Server list:

ServerList: 5 entries
  [1]: 29
  [2]: 57 <-------------------- Bridged device basic information cluster
  [3]: 3
  [4]: 30 <-------------------- Binding cluster
  [5]: 4

Client list:

ClientList: 3 entries
  [1]: 3
  [2]: 6 <---------------------- OnOff Cluster
  [3]: 4

2.3 Bind light to bridge

Follow the instruction in the light switch example to create a binding between the bridge and a Matter light. After that, pressing on the ESP-NOW switch will toggle both the LED on the bridge and the Matter light.

3. Device Perfromance

3.1 Memory Usage

The following is the Memory and Flash Usage.

• Bootup == Device just finished booting up. Device is not commissioned or connected to wifi yet.
• After Commissioning == Device is connected to wifi and is also commissioned and rebooted.
• After Creating Bridge == Device is bound to an ESP-NOW switch.
• device used: esp32c3_devkit_m
• tested on: 3d643be (2023-04-06)
• IDF: release/v5.1

	Bootup	After Commissioning	After Creating Bridge
Free Internal Memory	62KB	127KB	124KB

Flash Usage: Firmware binary size: 1.3MB

Note that the steps of commissioning and creating bridge are interchangable. This should give you a good idea about the amount of free memory that is available for you to run your application's code.

Applications that do not require BLE post commissioning, can disable it using app_ble_disable() once commissioning is complete.

4. Pending Issues

4.1 Responder Forwarding

Go to ESP-NOW component source, in src/control/src/espnow_ctrl.c, comment the call to espnow_ctrl_responder_forward(). The purpose of this function is to allow responders to forward received messages to other responders, increasing the range and reliability of message reception in ESP-NOW network. This function does not assume which channel the receivers are in, so it will switch to every Wi-Fi channel and perform an espnow send. However in the Matter network, after the bridge is commissioned, it is not allowed to switch channel. The call to this function will return error. To prevent unnecessary errors, it is recommend to disable the forwarding.

4.2 Channel for ESP-NOW Button

If the ESP-NOW switch used is an ESP-NOW button, it has little capability to switch channel when sending messages. If the bridge switches channel after commissioning, it is difficult for the ESP-NOW button to scan all channels to search for the bridge. In this case, set the Wi-Fi channel of the AP to channel 1 or 6, as these are the first two channels when the button performs scanning, hence more likely to finish scanning successfully before it loses power.