RP23CNC – RP235x-based 5-Axis grblHAL CNC Controller
RP23CNC is a 5-axis CNC controller board powered by the Raspberry Pi RP235x MCU, running the open-source grblHAL firmware.
WIZnet - WIZ610io
x 1
WIZnet - WIZ850io
x 1
Key Specifications
5-Axis Control
Step / Direction / Enable outputs (5V compatible)
Limit & Servo error inputs (12V compatible, LED indicators)
Standard Grbl Interface
Cycle Start, Feed Hold, Halt, Safety Door, Probe inputs
LED indicators included
Isolated Inputs
12V isolated input section, joinable to main 12V rail
Output Expansion
Flood, Mist, Aux0–2, Dust Collector
Relay Outputs
5V/12V selectable, up to 100mA drive
Flood, Mist, Aux0–2, Dust Collector, Spindle Enable
Spindle Control
PWM-based speed control
0–10V, 0–5V outputs
Enable / Direction / PWM (5V compatible)
Communication & Storage
2x UARTs
MicroSD card slot
Ethernet via WIZnet module
Power Section
12V main input + isolated input
5V and 3.3V regulators
Role of the WIZnet Chip
Hardware TCP/IP Offloading: RP235x focuses on motion control, while the WIZnet chip handles all TCP/IP networking.
Stable CNC Networking: Enables connection to remote PCs, IoT gateways, or web servers.
Scalability: Beyond local control, the WIZnet module allows network-based CNC + IoT integration projects.
Development History
V0.92 (Feb 2025): grblHAL boot confirmed, 5-axis motion verified, WIZnet Ethernet networking tested.
V0.95 (Mar 2025): Switched to USB-C, improved power efficiency, fixed UART pin mapping.
V1.0 (Apr 2025): Stable production release, available on Tindie.
Project Use Cases
The RP23CNC is not just a controller board – it’s a flexible platform that makers can adapt to their own projects:
Desktop CNC Machines
Build small CNC machines for wood or acrylic cutting
Control via web UI without a dedicated PC
IoT-enabled CNC Monitoring
Stream real-time CNC job status through the WIZnet module
Remote monitoring and emergency stop control
Educational CNC/Robotics Platform
Teach students G-code and motion control with grblHAL
Manage multiple devices over the network for hands-on learning
Custom Automation Equipment
Adapt for laser cutters, pick-and-place systems, or 3D printer conversions
Use digital outputs/relays to drive pumps, motors, or dust collectors
Remote CNC Farm Operation
Connect multiple CNCs via WIZnet networking
Centralized management from a server/cloud → small-scale smart manufacturing
Summary
RP235x MCU → Precise motion control
WIZnet Ethernet → Reliable network connectivity
grblHAL Support → Large open-source ecosystem
👉 The RP23CNC offers makers, researchers, and educators an affordable yet expandable CNC controller board that bridges motion control and networked automation.