ESP32 - WiFi Provisioning over BLE

Goal

The ESP-IDF API provides

An extensible mechanism to the developers to configure the device with the Wi-Fi credentials and/or other custom configuration using various transports and different security schemes. Depending on the use-case it provides a complete and ready solution for Wi-Fi network provisioning along with example iOS and Android applications. Or developers can extend the device-side and phone-app side implementations to accommodate their requirements for sending additional configuration data.

This component makes this API available as a component using the Bluetooth Low Energy (BLE GATT based) transport scheme. A phone (Android/iOS) is used to communicate with the ESP32 device over BLE. The phone app can discover and connect to the device without requiring user to go out of the phone app.

Example

An example can be found in the test directory.

1. Build, and flash the test/build/factory.bin.

2. Using the Espressif BLE Provisioning phone app, scan and connect to the ESP32. Then specify the WiFi SSID and password. Depending on the version of the app, you may have to change _ble_device_name_prefix to PROV_ in test/main/main.c, and change the config.service_uuid in ble_prov.c. Personally, I still use an older customized version of the app.

3. After provisioning the WiFi SSID and password are stored in the nvs partition of flash memory.

Usage

The software has been tested on the ESP-IDF SDK v4.1-beta2 and v4.3-dev-472-gcf056a7d0 with accompanying tools.

Clone this component in your project's components directory, or use it as a git submodule.

Copy the Kconfig.example to Kconfig and update the configuration.

In your project's sdkconfig.defaults, specify a custom partition.csv. An example of sdkconfig.defaults is shown below.

# Override some defaults so BT stack is enabled and
CONFIG_BT_ENABLED=y
CONFIG_BTDM_CONTROLLER_MODE_BLE_ONLY=y
CONFIG_BTDM_CONTROLLER_MODE_BR_EDR_ONLY=
CONFIG_BTDM_CONTROLLER_MODE_BTDM=
# factory binary is larger than default size
CONFIG_PARTITION_TABLE_CUSTOM=y
CONFIG_PARTITION_TABLE_CUSTOM_FILENAME=partitions.csv
CONFIG_PARTITION_TABLE_FILENAME=partitions.csv
# need 4 MByte flash for OTA updates
CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y

An example of partition.csv that includes factory and nvs partitions is shown below.

# Name,   Type, SubType, Offset,  Size, Flags
nvs,      data, nvs,      0x09000,  0x004000,
otadata,  data, ota,      0x0d000,  0x002000,
phy_init, data, phy,      0x0f000,  0x001000,
factory,  app,  factory,  0x010000, 0x150000,
ota_0,    app,  ota_0,    0x160000, 0x140000,
ota_1,    app,  ota_1,    0x2A0000, 0x140000,
coredump, data, coredump, 0x3E0000, 128k

Refer to the example in the test directory for details on how to integrate the ble_prov() functionality.

To provision the WiFi credentials using a phone app, this factory app advertises itself to the phone app. The Espressif BLE Provisioning app is available as source code or from the app stores:

• Android
• iOS

The WiFi SSID and password are stored in the nvs partition of flash memory.

OTA Update

To complete the experience, this provisioning should be combined with an OTA Update mechanism such as my ESP_OTA-Update repository. This allows the provisioning to trigger an OTA update of the application code.

A good place to initiate the OTA update would be after receiving IP_EVENT_STA_GOT_IP.

Feedback

We love to hear from you. Please use the Github discussion mechanisms to contact me.