Phil Barrett's PicoCNC Aims to Provide Professional Laser, Lathe, and Router Control at a Low Cost

Embedded engineer Phil Barrett has built a carrier PCB designed to turn the Raspberry Pi Pico, with its dual-core RP2040 microcontroller, into a low-cost yet flexible four-axis computer numeric control (CNC) board for routers, lathes, lasers, and more: the PicoCNC.

"This is a breakout board that along with a Raspberry Pi Pico becomes a CNC motion controller for devices like routers, mills, lasers, and lathes," Barrett explains of his creation. "Using grblHAL, it forms the basis of a motion control system with advanced features that you would have to pay multi-hundreds of dollars to get with other products. With a $4 USD Pico microcontroller, this is a very cost effective CNC controller."

The carrier board, compatible with the Raspberry Pi Pico and later wireless-capable Raspberry Pi Pico W plus any other RP2040-based boards sharing the same footprint, offers 5V control outputs for four axes — each with an independent enable. There are nine opto-isolated inputs, covering all standard Grbl controls plus limit switches for each axis. There are also seven relay outputs, for handling everything from extraction fans to coolant spray systems, and five extra 5V outputs for anything else you may need.

For storage, there's a microSD card socket, and control is provided over a USB connection or, if you fit the Raspberry Pi Pico W, over a Wi-Fi connection. There's a footprint for an optional EEPROM or FRAM storage chip, and I2C, SPI, and UART bus headers with mounts for optional daughter boards should the on-board capabilities miss something you need.

"PicoCNC can control most common CNC machines that hobbyists build or own," Barrett claims of the board's capabilities. "It provides a cost effective and significant improvement over the typical Arduino based controllers in that it has much higher step rate and is designed to handle electromagnetic interference. In addition, it has features you will find on professional CNC controllers like spindle control."

The PicoCNC is available on the Brookwood Design Tindie store at $42.99 as a a kit with all surface-mount parts already soldered, Raspberry Pi Pico or Pico W not included. Barrett has also released schematics for the board on GitHub under an unspecified license.