This project implements OpenHaystack firmware for ESP32C3 chips, allowing you to create Apple Find My network compatible accessory tags. The firmware is optimized for low power consumption and reliable operation.

• Features
• Requirements
• Installation
• Usage
• Configuration
• Troubleshooting
• Technical Details

• Low power consumption with optimized sleep modes
• Easy key generation and uploading through Python scripts
• Built on NimBLE for reliable Bluetooth LE operation

• PlatformIO (recommended) or Arduino IDE
• Python 3.7 or higher
• Python dependencies (install using pip install -r scripts/requirements.txt)

1. Clone this repository:

   git clone https://github.com/timbeh/esp32c3-openhaystack.git
   cd esp32c3-openhaystack

2. Install Python dependencies:

   pip install -r scripts/requirements.txt

3. Open the project in PlatformIO:

   pio project init

1. Connect your ESP32C3 board to your computer
2. Build and upload the firmware:

   pio run -t upload

1. Generate keys using the included keygen.py script (modified generate_keys.py from macless-haystack)

   python3 scripts/keygen.py

2. It will generate your keys into the scripts/output folder.

   • Copy the PREFIX_keyfile to the scripts/input folder
   • You can import the PREFIX_devices.json to the OpenHaystack macOS App

3. Upload the keys to your ESP32C3:

   python3 scripts/keywriter.py

   The script will:

   • Auto-detect your ESP32C3 device
   • Present a selection menu if multiple ports are found

   For manual port or keyfile specification:

   python3 scripts/keywriter.py -p /dev/tty.usbserial-XXXX -k your_keyfile

4. After uploading keys, reset the device. It will automatically start advertising.

1. No keys found in partition

   • Verify key upload using the keywriter script
   • Check the serial monitor for error messages

2. Device not visible in Find My

   • Ensure correct public keys are uploaded
   • Verify keys are registered in the OpenHaystack or equivalent app

3. Port not detected

   • Install correct USB drivers for your ESP32C3 board
   • Check device manager for COM port assignment

• Built on NimBLE for Bluetooth LE functionality
• Uses ESP32C3's low-power capabilities
• Stores keys in dedicated flash partition

The firmware is optimized for low power operation:

• Advertises for only 20ms
• Uses light sleep between advertisements

• Average current: ~20μA in sleep mode
• Peak current during advertisement: ~10mA
• Battery life depends on advertisement interval and sleep duration