Reticulum BLE Interface

A Bluetooth Low Energy (BLE) interface for Reticulum Network Stack, enabling mesh networking over BLE without additional hardware on Linux devices.

⚠️ Platform: Linux-only (requires BlueZ 5.x for GATT server functionality) ✅ Tested on: Raspberry Pi Zero W

Features

• Zero dongle requirements: Works with built-in BLE radios (Raspberry Pi, Linux laptops, etc.)
• Auto-discovery: Automatically finds and connects to nearby Reticulum BLE nodes
• Multi-peer mesh: Supports up to 7 simultaneous connections for mesh networking (may support more, untested)
• Dual mode operation: Acts as both central (scanner/client) and peripheral (advertiser/server)
• Connection prioritization: RSSI-based smart peer selection with connection history tracking
• Packet fragmentation: Handles BLE MTU limitations (20-512 bytes) transparently
• Enhanced error handling: Retry logic, exponential backoff, connection recovery
• Power management: Three power modes (aggressive/balanced/saver) for battery efficiency or CPU limitations. Saver mode tested on Raspberry Pi Zero W.

Installation

Prerequisites:

• Python 3.8 or higher
• Reticulum Network Stack already installed (installation guide)
• Linux with BlueZ 5.x

Option A: Automated Installation (Recommended)

The installation script automatically detects your Reticulum setup and installs dependencies in the correct environment:

# Download and run installer
git clone https://github.com/torlando-tech/ble-reticulum.git
cd ble-reticulum
chmod +x install.sh
./install.sh

# For custom config directory:
# ./install.sh --config /path/to/custom/config

The script will:

1. ✓ Detect if Reticulum is in a venv or system-wide
2. ✓ Install system dependencies (BlueZ, dbus)
3. ✓ Install Python packages in the correct environment
4. ✓ Copy BLE interface files to ~/.reticulum/interfaces/ (or custom config directory if specified)
5. ✓ Enable BlueZ experimental mode (required for proper BLE connectivity)
6. ✓ Optionally set up Bluetooth permissions

BlueZ Experimental Mode: The installer automatically enables BlueZ experimental mode, which is required for proper BLE connectivity. This allows the BLE interface to use LE-specific connection methods instead of defaulting to Classic Bluetooth (BR/EDR), preventing connection errors like "br-connection-profile-unavailable".

To skip this configuration (not recommended):

./install.sh --skip-experimental

Option B: Manual Installation

1. Install System Dependencies

Debian/Ubuntu/Raspberry Pi OS:

sudo apt-get update
sudo apt-get install python3-pip python3-gi python3-dbus python3-cairo bluez

Arch Linux:

sudo pacman -S base-devel gobject-introspection python-pip python-dbus python-cairo bluez bluez-utils

Why these packages?

• base-devel: Build tools (gcc, make, meson) required for compiling PyGObject
• gobject-introspection: Development files for GObject introspection (required for PyGObject compilation)
• python-dbus: D-Bus Python bindings for BlueZ communication
• python-cairo: Cairo graphics library
• bluez / bluez-utils: Bluetooth stack and utilities for Linux

Note for Arch users: PyGObject is intentionally NOT installed as a system package on Arch due to version incompatibility (Arch has 3.54.5, but bluezero requires <3.52.0). Instead, pip will compile the compatible PyGObject version (3.50.2) during installation. This adds ~2 minutes to installation time but ensures compatibility.

2. Install Python Dependencies

IMPORTANT: Install in the same environment as Reticulum!

Since we installed system packages for PyGObject, dbus-python, and pycairo in step 1, we only need to install the pure-Python packages:

If Reticulum is in a virtual environment:

# Activate the same venv where Reticulum is installed
source /path/to/reticulum-venv/bin/activate
pip install bleak==1.1.1 bluezero

If Reticulum is installed system-wide:

# Install system-wide (may need sudo)
pip install bleak==1.1.1 bluezero
# OR
sudo pip install bleak==1.1.1 bluezero

Note: The system packages (python3-gi, python3-dbus, python3-cairo) provide PyGObject, dbus-python, and pycairo, eliminating the need for lengthy compilation from source.

3. Copy BLE Interface Files

# Copy to Reticulum's interface directory
mkdir -p ~/.reticulum/interfaces
cp src/RNS/Interfaces/BLE*.py ~/.reticulum/interfaces/

4. Enable BlueZ Experimental Mode (Required)

BlueZ experimental mode is required for proper BLE connectivity. Without it, BlueZ may attempt Classic Bluetooth (BR/EDR) connections instead of BLE (LE) connections, causing connection failures.

Enable experimental mode (BlueZ >= 5.49):

sudo systemctl edit bluetooth

Add these lines:

[Service]
ExecStart=
ExecStart=/usr/lib/bluetooth/bluetoothd -E

Save and restart Bluetooth:

sudo systemctl daemon-reload
sudo systemctl restart bluetooth

Verify it's enabled:

ps aux | grep bluetoothd
# Should show: /usr/lib/bluetooth/bluetoothd -E

5. Grant Bluetooth Permissions

For non-root operation:

sudo setcap 'cap_net_raw,cap_net_admin+eip' $(which python3)

Note: If Reticulum is in a venv, grant permissions to that Python:

sudo setcap 'cap_net_raw,cap_net_admin+eip' /path/to/venv/bin/python3

Quick Start

1. Configure Reticulum

Add the BLE interface to your Reticulum configuration (~/.reticulum/config):

[[BLE Interface]]
  type = BLEInterface
  enabled = yes

  # Optional: customize device name
  # device_name = My-Reticulum-Node

For detailed configuration options, see examples/config_example.toml.

Custom Config Directory: If you use a custom Reticulum config directory with --config, the BLE interface will automatically use that directory to find its companion modules. No additional configuration needed!

2. Start Reticulum

rnsd --verbose

The interface will:

1. Start advertising as a peripheral (if enabled)
2. Scan for nearby BLE peers
3. Automatically connect to discovered peers
4. Form a mesh network with other BLE nodes

3. Verify Operation

# Check interface status
rnstatus

# Monitor announces
rnid -a

Configuration

The BLE interface supports extensive configuration options. See examples/config_example.toml for a fully documented example with all available options.

Key Configuration Options

• device_name: Advertised device name (auto-generated if not specified)
• service_uuid: BLE service UUID (must match on all devices)
• enable_peripheral: Accept incoming connections (default: yes)
• enable_central: Scan and connect to peers (default: yes)
• discovery_interval: How often to scan for new peers (default: 5.0 seconds)
• max_connections: Maximum simultaneous connections (default: 7)
• min_rssi: Minimum signal strength in dBm (default: -85)
• power_mode: Power management (aggressive/balanced/saver)

Testing

For detailed testing information, see TESTING.md.

Quick test using example script (no BLE hardware required):

cd examples
python ble_minimal_test.py test

Troubleshooting

No peers discovered

• Verify Bluetooth is enabled: bluetoothctl show
• Check service_uuid matches on all devices
• Try power_mode = aggressive for faster discovery
• Increase min_rssi to -90 for longer range

Connection timeouts

• Increase connection_timeout to 60
• Reduce max_connections to 3-5
• Check for BLE/WiFi interference (both use 2.4 GHz)
• Verify peer is within range (typically 10-30m)

GATT server failed to start

• Ensure BlueZ 5.x is installed: bluetoothd --version
• Check Bluetooth permissions (see Installation → Manual Installation → step 4)
• Try sudo rnsd temporarily to verify (not recommended for production)
• Set enable_peripheral = no to disable peripheral mode

Permission denied errors

• Grant capabilities to Python (see Installation → Manual Installation → step 5)
• Or run with sudo: sudo rnsd (not recommended)

BR/EDR connection errors (br-connection-profile-unavailable, ProfileUnavailable)

These errors occur when BlueZ attempts Classic Bluetooth (BR/EDR) connections instead of BLE (LE) connections. This is the most common BLE connection issue.

Symptoms:

• Devices connect then immediately disconnect
• Errors: "br-connection-profile-unavailable", "ProfileUnavailable"
• "ConnectDevice() unavailable" in logs
• Devices get blacklisted after multiple failures

Solution: Enable BlueZ experimental mode (see Installation → Manual Installation → step 4). If you used the automated installer, re-run it without --skip-experimental.

Bluetooth adapter not powered / "No powered Bluetooth adapters found"

The Bluetooth adapter exists but is powered off, preventing BLE operations.

Symptoms:

• Error: dbus.exceptions.DBusException: org.bluez.Error.Failed: Not Powered
• Error: BleakError: No powered Bluetooth adapters found.
• BLE interface fails to start or discover peers
• GATT server startup fails immediately

Cause: The Bluetooth adapter is in a powered-off state. This commonly happens on Raspberry Pi after boot or system updates.

Solution: Power on the Bluetooth adapter:

# Option 1: Using bluetoothctl (recommended)
bluetoothctl power on

# Option 2: If adapter is RF-blocked
sudo rfkill unblock bluetooth

# Option 3: Using hciconfig (older systems)
sudo hciconfig hci0 up

# Verify adapter is powered:
bluetoothctl show
# Should display "Powered: yes"

Automatic power-on at boot: Ensure Bluetooth service is enabled and starts at boot:

# Enable Bluetooth service
sudo systemctl enable bluetooth
sudo systemctl start bluetooth

# For persistent power-on, create a systemd service:
# See examples/bluetooth-power-on.service

The automated installer (v1.x+) automatically checks and powers on the Bluetooth adapter during installation.

Architecture

The BLE interface consists of four main components:

• BLEInterface.py: Main interface implementation, handles discovery and connections
• BLEGATTServer.py: GATT server for peripheral mode (accepting connections)
• BLEFragmentation.py: Packet fragmentation/reassembly for BLE MTU limits
• BLEAgent.py: Per-peer connection management

Development Setup

For contributors and developers who want to work on the BLE interface code itself.

Note: This setup is different from the production installation above. Use a virtual environment for development to avoid conflicts.

# Clone repository
git clone https://github.com/torlando-tech/ble-reticulum.git
cd ble-reticulum

# Create and activate virtual environment
python3 -m venv venv
source venv/bin/activate

# Install RNS (required for tests)
pip install rns

# Install all dependencies (runtime + development + testing)
pip install -r requirements-dev.txt

# Create package structure for tests
touch src/RNS/__init__.py
touch src/RNS/Interfaces/__init__.py

# Run tests
pytest

# Run tests with coverage
pytest --cov=src/RNS/Interfaces --cov-report=html

For detailed development and testing guidelines, see CONTRIBUTING.md and TESTING.md.

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for:

• Code style guidelines
• Pull request process
• Bug report templates
• Feature request guidelines

Supporting

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Reticulum Network Stack by Mark Qvist
• Built using bleak for BLE central operations
• Built using bluezero for GATT server

Links

• Reticulum Network Stack
• Reticulum Documentation
• Reticulum GitHub