Meshtastic Multiple Simultaneous Node Controller Demo

This project demonstrates a method for allowing multiple applications running on the same machine (e.g., a Raspberry Pi) to control and interact with a single Meshtastic node simultaneously.

How it Works

1. Physical Connection: A Meshtastic node is connected via USB to the host machine.
2. Serial-to-TCP Forwarding: The ser2net utility is configured to listen on a local TCP port (e.g., 4403) and forward all traffic to and from the Meshtastic node's serial port (e.g., /dev/ttyUSB0).
3. Application Connection: Multiple applications (simulated in multi_controller_demo.py) use the meshtastic-python library to connect to the node via the TCP socket (localhost:4403) provided by ser2net, instead of directly accessing the serial port.

This allows ser2net to manage the single serial connection while providing a network endpoint that multiple clients can connect to.

Prerequisites

1. Meshtastic Node: A Meshtastic compatible device (e.g., Heltec V3, RAK Wireless).
2. Host Machine: A computer capable of running Python and ser2net (e.g., Raspberry Pi, Linux PC).
3. Python 3: Ensure Python 3 is installed.
4. ser2net: Install ser2net (sudo apt update && sudo apt install ser2net on Debian/Ubuntu based systems).
5. meshtastic-python library: Install using pip (see Setup).

Setup

1. Connect Node: Connect your Meshtastic node to the host machine via USB. Identify its serial port (e.g., /dev/ttyUSB0 or /dev/ttyACM0) and note its serial baud rate (check device specs or Meshtastic settings, common values are 115200, 921600).
2. Configure ser2net:
   • Edit the ser2net configuration file. This is often /etc/ser2net.conf (older format) or /etc/ser2net.yaml (newer format). Check which one exists on your system.
   • Add a line/section to forward the node's serial port to a TCP port (default in the script is 4403).
   • Example for /etc/ser2net.conf:

     # FORMAT: <TCP PORT>:<STATE>:<TIMEOUT>:<DEVICE>:<OPTIONS>
     4403:raw:0:/dev/ttyUSB0:115200 8DATABITS NONE 1STOPBIT banner
     

     (Important: Replace /dev/ttyUSB0 with your node's actual serial port and 115200 with its correct baud rate)
   • Example for /etc/ser2net.yaml:

     connection: &meshtastic_forward
       accepter: tcp,4403             # Listen on TCP port 4403
       enable: on
       connector: serialdev,          # Connect to a serial device
         /dev/ttyUSB0,               # The serial device path <- CHANGE THIS
         115200n81                   # Serial settings: 115200 baud, no parity, 8 data bits, 1 stop bit <- CHANGE BAUDRATE IF NEEDED
                                     # Common alternatives: 921600n81, 460800n81

     (Important: Replace /dev/ttyUSB0 and 115200n81 as needed)
   • Save the configuration file.
3. Restart and Enable ser2net:

   sudo systemctl restart ser2net
   sudo systemctl enable ser2net  # Optional: Make it start on boot
   sudo systemctl status ser2net # Verify it's running without errors

4. Clone/Download Project: Get the project files (multi_controller_demo.py, requirements.txt, README.md) onto your host machine. Place them in a dedicated directory.
5. Install Dependencies: Navigate to the project directory in your terminal and run:

   pip install -r requirements.txt

   (It's recommended to use a Python virtual environment)

Running the Demo

Navigate to the project directory in your terminal and run the main script:

python multi_controller_demo.py

You should see output from both the "SimMeshSense" and "SimEASAlert" tasks, indicating they are connecting and interacting with the node concurrently via TCP. Press Ctrl+C to stop.

Troubleshooting

• Connection Refused: ser2net is likely not running or not listening on the expected port (4403 by default). Check sudo systemctl status ser2net and the configuration file.
• Connection Timeout / No Data: ser2net might be running, but the serial configuration (port /dev/ttyUSBx, baud rate) might be wrong, or the node might not be responding. Double-check the ser2net config and ensure the node is powered and connected. Try toggling noProto=True in the TCPInterface call within the Python script as a test.
• Permission Denied (Serial Port): The user running ser2net might not have permission to access the serial port. Add the user to the relevant group (often dialout): sudo usermod -a -G dialout $USER (log out and back in after).
• MeshtasticError: Check the specific error message. It might indicate issues with the node itself or the communication protocol.

Adapting for Real Applications

To use this method with actual applications like MeshSense or the Meshtastic EAS Alerter:

1. Complete the ser2net setup as described above.
2. Configure each application to connect to the Meshtastic node using its TCP connection option, pointing it to localhost (or 127.0.0.1) and the TCP port you configured in ser2net (e.g., 4403). Look for command-line arguments like --host localhost --port 4