Project Goal
The objective of this project is to completely reverse engineer the original Anycubic Kobra 3 Toolhead electronics and transform the factory PCB into a fully Klipper-compatible toolboard while preserving the original PCB, connectors, wiring harness and hardware.
The project aims to create comprehensive open hardware documentation covering the PCB architecture, electronic circuits, communication interfaces, peripheral connections and, eventually, a fully open firmware implementation.
Main Objectives
- Preserve the original PCB and connectors
- Full Klipper MCU support
- Native USB communication
- Extruder motor control
- Heater control
- Part cooling and hotend fan control
- Thermistor support
- LED control
- Filament sensor support
- Load Cell support
- Complete hardware documentation
- Open-source firmware
- Open reverse engineering database
Current Status
Hardware reverse engineering has made significant progress. The project has evolved beyond simple component identification into a structured hardware database documenting the relationships between the MCU, peripherals, connectors and test points.
Currently Documented
- ✔ Complete GD32F303CBT6 MCU pin database
- ✔ SWD debugging interface
- ✔ Debug UART interface
- ✔ SP3232 RS232 communication interface
- ✔ CS1237 Load Cell ADC communication
- ✔ Load Cell connector mapping
- ✔ Main Print Port power distribution and partial signal mapping
- ✔ LED connector mapping
- ✔ Fan connector identification
- ✔ Heater connector identification
- ✔ Initial TMC2209 control signal mapping
- ✔ Test Point database
Every new measurement is added to a centralized hardware database, allowing every signal to be traced between the MCU, connectors and external peripherals.
Next Milestones
- Complete identification of every Print Port signal
- Fully document the TMC2209 interface
- Map all remaining GPIO assignments
- Document the complete power and control network
- Develop a custom bootloader
- Create the first custom firmware
- Implement native Klipper toolboard support
Long-Term Goal
The final objective is to provide the community with a fully documented hardware platform and an open-source firmware that enables the original Anycubic Kobra 3 Toolhead PCB to operate as a standalone Klipper-compatible toolboard.
The documentation is continuously updated as new measurements are verified, ensuring that the entire reverse engineering process remains transparent, reproducible and useful for the community.
Key features
Project images
Frequently asked questions
What is the goal of this project?
To convert the original Anycubic Kobra 3 toolhead electronics into a Klipper-compatible toolboard.
Will it work with the original printer?
Yes. The project keeps the original hardware and connectors whenever possible.
Which MCU is used?
GD32F303CBT6 ARM Cortex-M4 microcontroller.
Which firmware will be used?
Custom Klipper MCU firmware.
Can the original extruder be reused?
Yes. Keeping the factory extruder is one of the primary goals.
Will the original fans work?
Yes. Both the hotend and part cooling fans are planned to be supported.
Can the LEDs be controlled?
Yes. Both LEDs will be independently controllable.
Will USB communication be available?
Yes. The current design is based on a CH340 USB-UART interface.
Will the filament sensor work?
Yes. Support is planned.
Will the load cell be supported?
Yes. Reverse engineering is currently in progress.
Will the project be open source?
The documentation and hardware development are community driven.
When will it be finished?
The project is under active development and progress will be published regularly.
Anycubic Kobra 3 Toolhead Mod
Reverse engineering the original Anycubic Kobra 3 toolhead electronics and converting it into a Klipper-compatible toolboard.