RiceCNC is a system for controlling Computer Numeric Control (CNC) milling machines having a low level step/direction or discrete stepper motor drive interface. Because USB delays prevent direct motor stepping, this integrated hardware/software solution uses an intermediate micro-processor board to relieve the host computer and USB interface of real-time considerations.

An inexpensive ($26.95) Digilent "Chipkit" UNO32 µP board is available from Newark element14 or directly from Digilent. The high end 32 bit µP has impressive performance capable of micro-stepping four or more motors concurrently at high audio frequency while interpolating linear and cubic bezier paths with double precision at a rate of 500 times a second.

The required UNO32 firmware is included in the application package. A companion product, the "Uno32-DB25 Connection Kit" is available on eBay that provides cables and connectors facilitating easy interconnection of the UNO32 with a typical motor driver board having a 25 pin parallel input, e.g., HobbyCNC and MaxNC. It also enables connection to relays and driver boards having current-loop inputs, e.g., CW230.

The app supports interactive jog, run, linear, circular and drill cycle coordinated movement for simple machining operations. Multi-touch trackpad dragging can be configured to control continuous jogging such as to follow a pencil line.

For more complex and repeatable operations, the app supports CNC programs using a subset of the RS-274 (G-Code) dialect with many extensions for program control, cubic bezier curves and readability.