Rabbit Board 4-Axis

The Rabbit Board 4-Axis is designed as the motion-control core of a CNC machine. It runs on an ESP32-WROOM-32U module and provides dedicated STEP/DIR outputs for X, Y, Z, and A axes, making it suitable for routers, mills, plasma tables, laser machines, and custom CNC builds.

With Rabbit GRBL firmware pre-installed, the board is ready for GRBL-compatible workflows while keeping the hardware layout practical for real control boxes and machine wiring.

Because it follows the GRBL communication workflow, Rabbit Board 4-Axis can be used with G-code sender applications that support GRBL firmware, including Universal Gcode Sender, Focus, and other GRBL-compatible senders.

The STEP/DIR signals for all four axes are routed through a 74ACT245 buffer, instead of driving external motion hardware directly from the ESP32 pins.

This helps provide clean logic-level signals for stepper or servo drivers, improves signal integrity, and makes the controller better suited for demanding CNC environments where long wiring, electrical noise, and external driver electronics are common.

Limit switch inputs and the probe input are opto-isolated using LTV-817S optocouplers. The limit switch side is powered from a dedicated 12V field input, keeping noisy machine wiring separated from the controller logic.

This design helps with reliable homing, probing, and fault detection in real workshop conditions, especially when the machine uses motors, spindles, relays, and long cable runs.

The controller includes a protected and filtered 12V DC input with reverse polarity protection, an input inductor, and filtering capacitors. This helps reduce incoming electrical noise before power is regulated for the controller electronics.

The board then generates stable 5V and 3.3V rails for the USB interface, logic buffers, and ESP32 controller. This power architecture is important for CNC control boxes, where the electronics must stay stable while sharing the same environment with motor drivers, power supplies, and spindle equipment.

The Rabbit Board uses a USB Type-B connector and a CP2102 USB-to-serial interface for a robust PC connection. The USB hardware is suitable for a machine controller enclosure where a stronger connector is preferred over fragile board-mounted micro USB ports.

The controller is built around an ESP32-WROOM-32U module with an external antenna connector, allowing Rabbit GRBL to support WiFi-based workflows when wireless control is preferred. USB remains the dependable wired option, while WiFi gives flexibility for modern CNC setups.

Beyond the four motion axes, the board exposes practical CNC outputs including spindle PWM, spindle direction, mist coolant, flood coolant, and the probe input terminals.

Additional auxiliary outputs such as ATC lock, ATC blow, and ATC door make the Rabbit Board useful as a complete control interface, not only as a basic step generator.

The Rabbit Board is the hardware layer of the SourceRabbit CNC ecosystem. It works together with Rabbit GRBL firmware, Focus CNC control software, and RabbitCAM toolpath generation.

RabbitCAM prepares toolpaths from design files, Focus sends and controls the CNC job, Rabbit GRBL runs the motion firmware, and the Rabbit Board turns that workflow into real machine signals.