Remote Framebuffer VNC Server for the Elegoo Centauri Carbon
OpenCentauri-VNC is a lightweight VNC (RFB) server designed specifically for the Elegoo Centauri Carbon (ECC) running OpenCentauri.
It streams the printer’s touchscreen interface directly from /dev/fb0, allowing you to remotely view exactly what appears on the printer’s display without modifying firmware, rebuilding the UI, or installing heavyweight services that could impact print stability.
- This project implements a VNC server, not a VNC viewer/client.
- The current implementation is view-only due to platform constraints.
- Input injection (touch, keyboard, mouse) is not implemented at this time, but interactive access may be possible in the future if safe and reliable mechanisms become available.
- Installation via USB (
/mnt/exUDISK) is temporary and intended only for development and testing. No permanent changes are made to the printer firmware by default.
The Elegoo Centauri Carbon:
- Uses a direct framebuffer UI (
/dev/fb0) rather than X11 or Wayland - Runs on an embedded Linux platform (OpenCentauri)
- Does not provide native remote display functionality
- Should not be burdened with background services that could impact long prints
OpenCentauri-VNC provides a low-impact, display-only solution that respects these constraints.
- Reads directly from
/dev/fb0used by the Centauri Carbon UI - Requires no modification of firmware or UI components
- Built as a static binary (musl) to avoid glibc compatibility issues
- Predictable and bounded resource usage
- Adjustable frame rate (default: 3 FPS)
- Single-client connection
- Uses standard RFB / VNC 3.8
- RAW encoding only
- No input injection (touch, keyboard, or mouse)
- No authentication or encryption
- No compression or advanced encodings
- Not intended as a general-purpose desktop VNC server
These are current technical limitations, not intentional product features.
Future versions may explore interactive access if it can be implemented safely without risking print reliability.
With OpenCentauri-VNC, you can:
- Monitor prints remotely
- Observe printer state and progress
- Verify temperatures, menus, and UI behavior
- Capture screenshots or recordings for diagnostics
- Check printer status without physical access
All without rebuilding firmware or modifying vendor software.
Although designed specifically for the Elegoo Centauri Carbon and OpenCentauri, this approach may also be applicable to other embedded Linux devices that render their UI directly to /dev/fb0, such as:
- Other embedded printers or CNC controllers
- LVGL-based appliances
- OpenWrt systems with framebuffer UIs
- Industrial HMIs or kiosk devices
These are incidental use cases, not the primary focus of this project.
- Zig 0.12.0 or newer
- Linux build environment (Ubuntu / WSL tested)
zig cc -O2 -static \
-target arm-linux-musleabihf \
-mcpu=generic+v7a \
-o OpenCentauri-VNC fb0rfb.cThis produces a fully static ARM binary compatible with OpenCentauri.
⚠️ Note: Installation via USB (/mnt/exUDISK) is temporary and intended only for development and testing.
Copy the binary to the printer:
scp OpenCentauri-VNC root@PRINTER_IP:/mnt/exUDISK/bin/On the printer:
cd /mnt/exUDISK/bin
chmod +x OpenCentauri-VNC
nice -n 19 ./OpenCentauri-VNC --fps 3Connect using a VNC viewer to:
PRINTER_IP:5900
- TigerVNC
- TightVNC
- UltraVNC
-f /dev/fb0 Framebuffer device (default: /dev/fb0)
-p 5900 TCP port (default: 5900)
--fps N Frames per second (default: 3, max: 15)
Lower FPS results in lower CPU usage.
- Role: VNC server
- Framebuffer source:
/dev/fb0 - Protocol: RFB / VNC 3.8
- Encoding: RAW
- Binary: Static (musl)
- Security: None (LAN use only)
- Designed for predictable, low-impact operation
This software provides no authentication or encryption.
It is intended for trusted local networks only.
Do not expose it directly to the internet.
This project was developed with assistance from ChatGPT 5.2.
Design discussion, code review, documentation, and build strategy were aided by AI-generated analysis and suggestions, with final implementation and testing performed by the project author.
Thanks to the team at OpenCentauri for building an alternative firmware for the Elegoo Centauri Carbon — and especially for including SSH support. Having reliable SSH access turns the device from a sealed appliance into something you can actually work with: inspect, debug, automate, and build tools like this without invasive hardware mods. Your work makes real experimentation possible while keeping the platform approachable for the community.
MIT License