ESP HomeKit SDK

Introduction

HomeKit is a framework developed by Apple for communicating with and controlling connected accessories in a user’s home using iOS devices. ESP HomeKit SDK has been developed in-house by Espressif to build Apple HomeKit compatible accessories using ESP32/ESP32-S2/ESP8266 SoCs.

Note: If you want to use HomeKit for commercial products, please check here for access to the MFi variant of this SDK. It has the exact same APIs as this and so, moving to it should be easy. However, commercial HomeKit products can be built only with ESP32/ESP32-S2 since ESP8266 cannot meet all the HomeKit Certification requirements.

If you want to use a port of Apple's ADK instead, please check here

Features of this SDK:

Easy APIs to implement all standard HomeKit profiles defined by Apple.
Facility to add customised accessory specific Services and Characteristics.
Samples (Fan, Lightbulb, Outlet, Bridge, Data-TLV8, Ethernet) to enable quick accessory development.
Support for ESP Unified Provisioning.

Get Started

Set up Host environment

Set up the host environment and ESP IDF (master branch) as per the steps given here.

If you are using ESP8266, set-up ESP8266-RTOS-SDK (master branch) as per the steps given here.

Get esp-homekit-sdk

Please clone this repository using the below command:

git clone --recursive https://github.com/espressif/esp-homekit-sdk.git

Note the --recursive option. This is required to pull in the JSON dependencies into esp-homekit-sdk. In case you have already cloned the repository without this option, execute this to pull in the submodules: git submodule update --init --recursive

Compile and Flash

You can use esp-homekit-sdk with any ESP32, ESP32-S2 or ESP8266 board (though we have tested only with the ESP32-DevKit-C, ESP32-S2-Saola-1 and ESP8266-DevKit-C). We have provided multiple examples for reference. Compile and flash as below (fan used as example):

For ESP32/ESP32-S2

$ cd /path/to/esp-homekit-sdk/examples/fan
$ export ESPPORT=/dev/tty.SLAB_USBtoUART #Set your board's serial port here
$ idf.py set-target <esp32/esp32s2>
$ idf.py flash monitor

For ESP8266

$ cd /path/to/esp-homekit-sdk/examples/fan
$ export ESPPORT=/dev/tty.SLAB_USBtoUART #Set your board's serial port here
$ make defconfig
$ make flash monitor

As the device boots up, you will see two QR codes, a small one for HomeKit and a larger one for Wi-Fi provisioning. Please use any of the Espressif Provisioning Apps for Wi-Fi provisioning.

Note: For the Open source HomeKit SDK, the HomeKit QR code cannot be used for provisioning from the Home app. It can be used only for pairing, after the Wi-Fi provisioning is done. For provisioning from Home app, you will need the MFi variant of the SDK.

Note: If you want to use hard-coded credentials instead of Provisioning, please set the ssid and passphrase by navigating to idf.py menuconfig -> App Wi-Fi -> Source of Wi-Fi Credentials -> Use Hardcoded

After the device connects to your Home Wi-Fi network it can be added in the Home app

Add acccessory in the Home app

Open the Home app on your iPhone/iPad and follow these steps

Tap on "Add Accessory" and scan the small QR code mentioned above.
If QR code is not visible correctly, you may use the link printed on the serial terminal or follow these steps:
- Choose the "I Don't Have a Code or Cannot Scan" option.
- Tap on "Esp-Fan-xxxxxx" in the list of Nearby Accessories.
- Select the "Add Anyway" option for the "Uncertified Accessory" prompt.
- Enter 11122333 as the Setup code.
You should eventually see the "Esp-Fan-xxxxxx added" message.
Give a custom name, assign to a room, create scenes as required and you are done.

For ESP8266, the pairing may take a bit longer.

Changing the Setup Code

The HomeKit setup code can be changed by using the CONFIG_EXAMPLE_SETUP_CODE config option (idf.py menuconfig -> Example Configuration -> HomeKit Setup Code). Please also refer the HomeKit Setup Configuration below.

Using Standard Apple HomeKit Profiles

The examples provided in the SDK are for fan, outlet, lightbulb. For using any other standard profiles, please refer the files under components/homekit/hap_apple_profiles/.

Adding Custom Profiles

Please refer the Firmware Upgrades Custom Profile (components/homekit/extras/) to see how to add your own profile. You can use some UUID generator like this to generate your own UUIDs for the services and characteristics.

HomeKit Setup Configuration

As per the HomeKit requirements, the raw setup code should not be stored on the accessory. Instead, the SRP Salt and Verifier generated from the code should be stored. This salt-verifier combination, called as setup info in the ESP HomeKit SDK, needs to be unique for every accessory. This can be provided to the HAP Core using the hap_set_setup_info() API. Another parameter required for setup is the setup id, which also needs to be unique. It is provided to the HAP Core using hap_set_setup_id() API.

In order to ease the task of providing unique setup info and setup id for each accessory, instead of using the above APIs, the same information can be stored in a separate flash partition called factory_nvs (Please see the partitions_hap.csv file in any example). This allows to keep the same firmware image and just flash different factory_nvs images for different accessories. The factory_nvs image fan_factory.bin has been provided for Fan, which can be flashed using esptool. Custom images can be created using the factory_nvs_gen utility in tools/ as below

Usage:

./factory_nvs_gen.py 11122333 ES32 factory

Replace ES32 and 11122333 with the setup code and setup id of your choice. This has been tested with Python 3.7.3.

Flash this using the esptool as below.

$ esptool.py -p $ESPPORT write_flash 0x340000 factory.bin

To use the setup info from this image, you will have to disable the hardcoded setup code by setting CONFIG_EXAMPLE_SETUP_CODE=n (idf.py menuconfig -> Example Configuration -> Use hard-coded setup code -> disable).

The factory_nvs partition can also hold other information like serial numbers, cloud credentials, firmware verification keys, etc. For that, just create a CSV file as per the requirements of NVS Partition Generator Utility and provide it to the factory_nvs_gen using the --infile option. These variables (if stored as binary data) can then be read in the accessory code using hap_factory_keystore_get() API.

Sample CSV (say sample.csv)

key,type,encoding,value
app,namespace,,
serial_num,data,binary,12345