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Networking & Connectivity

grblHAL offers powerful networking capabilities that go beyond standard USB connections. Depending on your controller hardware (e.g., Teensy 4.1, ESP32, RP2040), you may have access to Ethernet, Wi-Fi, Bluetooth, and a dedicated WebUI.

This guide covers the setup and configuration for these advanced connectivity options.

Ethernet​

Ethernet provides a robust, interference-resistant connection ideal for production environments. It eliminates USB length limits and susceptibility to EMI (Electro-Magnetic Interference).

Basic PC Setup (Direct Connection)​

If you are connecting your PC directly to the controller (without a router/switch in between), you must configure a Static IP on your computer's network adapter.

Note: These steps follow the Sienci Labs SLB Ethernet Guide.

1. Configure the Controller (Static IP)​

First, connect via USB and configure grblHAL to use a Static IP address. This ensures the controller always has a known address.

  • IP Mode: Static
  • IP Address: e.g., 192.168.5.15
  • Gateway: 192.168.5.1
  • Netmask: 255.255.255.0

Check your specific board documentation for the exact $ settings to configure IP parameters.

2. Configure Windows Network Adapter​

  1. Connect the Ethernet cable between your PC and the controller.
  2. On Windows, search for "View network connections".
  3. Right-click your Ethernet adapter (often "Ethernet 2" or similar) and select Properties.
  4. Select Internet Protocol Version 4 (TCP/IPv4) and click Properties.
  5. Select "Use the following IP address":
    • IP address: 192.168.5.5 (Must be different from the controller, but in the same range)
    • Subnet mask: 255.255.255.0
    • Default gateway: Leave blank or use 192.168.5.1.
  6. Click OK to save.

3. Connect via G-Code Sender​

  • Open your sender (e.g., gSender, ioSender).
  • Select Ethernet/Network as the connection type.
  • Enter the controller's IP address (192.168.5.15) and Port (usually 23).
  • Click Connect.

Wi-Fi​

Wi-Fi allows for wireless control and is available on chips like the ESP32 and Raspberry Pi Pico W. You can typically operate in two modes:

The controller connects to your existing home/workshop Wi-Fi network.

  • Range: limited by your router's signal.
  • Access: Any device on the network can control the machine.

Configuration: You typically need to set the SSID (Network Name) and Password via USB first.

  • $74=<SSID>
  • $75=<Password>
  • $73=1 (Enable Wi-Fi / Station Mode) (Note: Setting numbers can vary by driver key. Use $S or $P to list available settings)

2. Access Point (AP) Mode​

The controller creates its own Wi-Fi network that you connect your PC to.

  • Range: Limited to the controller's antenna.
  • Access: Direct connection; no router needed.

WebUI (Plugin_WebUI)​

Many network-enabled grblHAL builds (especially ESP32, RP2040, and Teensy 4.1) include an embedded Web User Interface. This allows you to control the machine from any device with a browser (PC, Tablet, Smartphone) without installing software.

Features​

The WebUI is surprisingly powerful and includes:

  • Dashboard: real-time DRO (Digital Readout), Jogging, Homing, and Macro buttons.
  • File Management: Upload, delete, and run G-code files directly from the SD card.
  • Console: Send manually typed G-code commands and view the output log.
  • Configuration: Easy-to-use forms for changing grblHAL $ settings without memorizing numbers.
  • Tablet Mode: A touch-friendly interface optimized for mounting a tablet on your machine.
  • Camera Support: View a stream from an ESP32-CAM or similar URL.

Installation & Compatibility​

  • Build Option: The WebUI must be enabled at compile time (or selected in the Web Builder).
  • File Storage:
    • FlashFS (Recommended): The WebUI files (index.html.gz, etc.) are compressed and stored in the controller's internal flash memory. This is faster and doesn't require an SD card for the UI itself.
    • SD Card: On some older or memory-constrained builds, you may need to copy the index.html.gz file to the root of your SD card.

Essential Settings​

If the WebUI is active but you cannot connect, check these settings via USB:

SettingDescriptionRecommended Value
$306HTTP Port: The port for the web server.80
$307WebSocket Port: The port for real-time data.81
$300Hostname: The network name of the device.grblhal
$70Network Services: Bitmask to enable services.15 (enables HTTP, Telnet, MDNS, etc.)

How to Access​

  1. Connect your machine to Wi-Fi (see above) or Ethernet.
  2. Find the IP address (type $I in a serial terminal if you don't know it).
  3. Open a web browser on a device connected to the same network.
  4. Type http://<IP_ADDRESS> (e.g., http://192.168.1.50).
    • Tip: If you set a hostname, you might be able to access it via http://grblhal.local depending on your network.

Bluetooth​

Bluetooth allows for wireless serial communication, effectively replacing the USB cable with a wireless link. It is commonly used for wireless pendants or simple control apps.

Setup & Pairing​

  1. Enable: Bluetooth is usually enabled at compile-time (BLUETOOTH_ENABLE).
  2. Pairing:
    • On your PC/Phone, scan for Bluetooth devices.
    • Look for a device named grblHAL (or similar).
    • Pair with it (default PIN is often 1234 or 0000).
  3. Connection:
    • Once paired, the OS assigns a COM Port (Windows) or device file (Linux/Mac).
    • In your G-code sender, select this COM Port and the appropriate baud rate (Bluetooth often negotiates speed automatically, but try 115200).

Tip: Bluetooth can have higher latency than USB or Ethernet. It is great for pendants but less ideal for sending large, high-speed G-code files directly.