ESP32

OpenHaystack Firmware for ESP32

This project contains a PoC firmware for Espressif ESP32 chips (like ESP32-WROOM or ESP32-WROVER, but not ESP32-S2). After flashing our firmware, the device sends out Bluetooth Low Energy advertisements such that it can be found by Apple's Find My network.

Disclaimer

Note that the firmware is just a proof-of-concept and currently only implements advertising a single static key. This means that devices running this firmware are trackable by other devices in proximity.

Requirements

To change and rebuild the firmware, you need Espressif's IoT Development Framework (ESP-IDF). Installation instructions for the latest version of the ESP-IDF can be found in its documentation. The firmware is tested on version 4.2.

For deploying the firmware, you need Python 3 on your path, either as python3 (preferred) or as python, and the venv module needs to be available.

Build

With the ESP-IDF on your $PATH, you can use idf.py to build the application from within this directory:

idf.py build

This will create the following files:

• build/bootloader/bootloader.bin -- The second stage bootloader
• build/partition_table/partition-table.bin -- The partition table
• build/openhaystack.bin -- The application itself

These files are required for the next step: Deploy the firmware.

Deploy the Firmware

Use the flash_esp32.sh script to deploy the firmware and a public key to an ESP32 device connected to your local machine:

./flash_esp32.sh -p /dev/yourSerialPort "Base64-encoded advertisement key"

Note: You might need to reset your device after running the script before it starts sending advertisements.

For more options, see ./flash-esp32.h --help.