A robust program for your ESP32 to capture and replay SubGHz frequencies, inspired by the Flipper Zero and written in Arduino (C++).

• Frequency Analyzer: Scan and analyze nearby devices and their frequencies with ease.
• Record RAW: Capture and record nearby signals with precise RSSI configuration.
• Replay RAW: Replay previously captured signals from a file (no SD card required).
• Preset Configuration: Configure the frequency of your device, and set the preset modulation (just like the Flipper Zero!).
• Flipper Zero Support: Effortlessly replay any Flipper Zero SUB file, including the many publicly available ones, whenever you need.

BKFZ SubGHz utilizes the Flipper Zero SUB file format to save and replay signals, ensuring seamless compatibility between both devices (Flipper Zero not needed!).

To start, you'll need (by minimum) an ESP32 [$2.97] of your choice and a CC1101 RF Transceiver [$2.01]. You can purchase both of these parts in the links provided (I chose an ESP32-D1-Mini because of its size and price, but a standard ESP32 w/ voltage regulator will also be sufficient. I am also using a CC1101 module with an SMA connector, but these tend to be more expensive).

If you're looking to build a fully-fledged BKFZ SubGHz device, you'll want to purchase these additional components (about ~$13.03):

• 2000mAh Lithium Battery: $6.03 on AliExpress (ensure your ESP32 includes a built-in voltage regulator, or attach one separately)
• TP4056 Module (5pk): $1.36 on AliExpress
• Latching Buttons (10pk): $1.13 on AliExpress
• JST 2mm Connectors (10pk): $1.01 on AliExpress
• Custom PCB Print: ~$3.50 on JLCPCB (w/ shipping)

The custom PCB design, as found here, is specifically designed to work with the 433 MHz module(s) linked above.

To flash the BKFZ SubGHz program on your ESP32, you'll need to connect the CC1101 module first. By default, the following pinout is used:

If you'd like to use a different pinout, you can configure the proper pins in the config.h configuration file (located in the config folder). Once you've connected the ESP32 to your computer, you'll need to download and install the Arduino IDE, as well as the LittleFS Upload plugin (you can find instructions on installation and usage in the repository). The plugin is crucial to serve essential files through the web server (CSS, fonts, icons, etc).

After installing the IDE, download the latest release for this repository and extract the ZIP file. Then, launch the BKFZ_SubGHz.ino file located inside the folder, and upload the data files through LittleFS (Ctrl + Shift + P, then Upload LittleFS to Pico/ESP8266/ESP32). Make sure your Serial Monitor is closed during the uploading process.

Lastly, click the Upload icon in the Arduino IDE to flash the code on your ESP32. You'll see Hard resetting via RTS pin... once the writing is complete.

To access the user interface of the BKFZ SubGHz, open the WiFi settings on your mobile device and connect to the BKFZ SubGHz WiFi network (you can configure the SSID and password in the config.h file of the project). Once you're connected to the WiFi network, open your browser and navigate to 192.168.4.1. If the page is not found, check the Gateway IP address of the WiFi network and navigate to that IP address.

If you'd like to add the user interface as a web app to your home screen, you can click Share > Add to Home Screeneen in Safari (for Android, click the 3 dots in Chrome).

Finally, open the settings tab on the user interface to configure the frequency, preset, and RSSI. Once you've configured these settings, you're all set!

If you'd like to configure the settings used by the BKFZ SubGHZ, modify the default user configuration, or manage presets, modify the following files:

• headers/config.h: Stores device configuration such as CC1101 pin-out, WiFi/BLE mode, and recording parameters.
• presets.cpp: Stores the list of available SubGHz presets (as used by the Flipper Zero) and their CC1101 register configurations. Declarations in headers/presets.h.
• user_settings.cpp: Stores all user-configurable settings as well as their available options, including frequencies, RSSI thresholds, etc. Declarations in headers/user_settings.h.

If you'd like to customize the user interface, you can find all of the HTML files in the static folder. Additionally, custom fonts, icons, and other libraries such as JQuery are found in the data folder (as used by LittleFS). All of these files are served at /static.

This project was made possible by utilizing the following dependencies:

• ELECHOUSE_CC1101_SRC_DRV | A library for controlling the CC1101 RF module, which is commonly used for wireless communication in Arduino projects.
• ESPAsyncWebServer | A library that enables the creation of web servers on the ESP32 and ESP8266.
• ArduinoJson | A library for efficiently handling JSON data in Arduino projects, useful for parsing and generating JSON files.
• ESP32 Core Libraries | A collection of libraries pre-installed on the ESP32 (including Wi-Fi, SPI, LittleFS, Preferences, and much more).
• Flipper Zero | This project couldn't be made possible without the extensive documentation and awesome team over at Flipper Zero ♥

Unlike the Flipper Zero, the BKFZ SubGHz configures the CC1101 to filter out background noise that could interfere with recording. This functionality is intentional to ensure a greater accuracy during the capturing process.

No, the BKFZ SubGHz can not copy any of these types of devices, unlike the Flipper Zero. This project is specifically focused on replicating the SubGHz functionality of the Flipper Zero. However, it is technically possible to achieve this with an ESP32 and the appropriate module (though it's unlikely to happen). However, contributions to the project are always welcome!

To operate your BKFZ SubGHz, you'll need to connect to its WiFi network. However, this doesn't require an internet connection, as the BKFZ SubGHz functions entirely offline. To access the user interface, you'll need to check the gateway IP of the BKFZ SubGHz WiFi network (which is usually 192.168.4.1).

At the moment, this project is solely developed and maintained by me (thanks to the amazing resources here). That said, I highly encourage you to contribute to the project by submitting a pull request! It would be greatly appreciated.

That's great to hear! You can submit any feedback, or any bugs that you find, on the issues page. I check these very frequently, and I highly encourage you to find bugs.

I'm glad to hear that you find this project useful! If you'd like to support this project and its development, you can send me a donation here :)

Made with ♡ by Briann