Bitle v0.1

Bitle is a self-powered ESP32-C3 BitChat relay node. It extends BitChat’s Bluetooth mesh by hosting a dedicated BLE gateway that handles Noise XX handshakes, validates BitChat packets, and re-broadcasts encrypted payloads without user interaction. The current hardware uses an ESP32-C3 with a flexible 2.4 GHz antenna, weatherproof enclosure, solar input, and battery pack. Bitle is well suited to extend the mesh network range in places like remote trails, campsites, or any offline comms grid.

Features

• Full BitChat handshake – Implements the Noise XX pattern with the upstream noise_ref library, performing Ed25519 identity binding like the mobile apps.
• BLE mesh relay – Runs a NimBLE GATT service that BitChat clients subscribe to; packets are encoded/decoded with the BitChat binary format and forwarded transparently.
• Time sync & nicknames – Maintains a BLE-derived epoch for packet timestamps and advertises deterministic anon#### nicknames (configurable through NVS).
• Ready for solar/battery deployments – Firmware is autonomous; once flashed it will advertise, accept connections, and keep the mesh alive indefinitely.

Repository layout

├── CMakeLists.txt        # ESP-IDF project entry
├── sdkconfig.defaults   # Recommended configuration seed
├── components/
│   ├── bitchat_utils/   # Time sync helper used by the firmware
│   └── noise_ref/       # Bundled Noise-C reference library
└── main/
    ├── main.c
    ├── bitchat_ble.{c,h}
    ├── noise_handshake.{c,h}
    ├── packet_codec.{c,h}
    └── nickname_manager.{c,h}

Building & flashing

The firmware has been developed and tested with ESP-IDF v6.0, though other recent 5.x/6.x releases should also work.

Prerequisites

• ESP-IDF installed (recommended: ~/esp-idf)
• Toolchain exported in the current shell before running build commands:

source ~/esp-idf/export.sh

idf.py set-target esp32c3
idf.py build
idf.py -p /dev/cu.usbmodem101 flash monitor

Adjust the serial port (-p) for your setup. sdkconfig will be generated from sdkconfig.defaults during the first build.

License

This project is licensed under the MIT License.
You are free to use, modify, and distribute this software, provided that attribution is given to the original author.

• Firmware source: © 2025 Mark Soares, released under the MIT License.
• components/noise_ref: Noise-C reference library (MIT-style). Review the upstream license before redistribution.

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For field deployment, drop the firmware onto an ESP32-C3 in your Bitle enclosure, connect power, and the node will immediately begin extending nearby BitChat meshes.