The Create USB Interface is an open source microcontroller board that can be programmed in C, BASIC, or Arduino languages. The latest version is called the CUI32Stem, and it is designed to work ‘hand-in-hand’ with the GROVE prototyping system that includes a wide range of sensors and actuators. It utilizes a high-performance Microchip® PIC32 microcontroller unit to allow programmable user interfaces. Its development and typical uses are described, focusing on musical interaction design scenarios. Several options for wireless connectivity are described as well, enabling the CUI32Stem to pair with a smartphone and/or a normal computer. Finally, SeeedStudio’s GROVE system is explained, which provides a prototyping system comprised of various elements that incorporate simple plugs, allowing the CUI32Stem to easily connect to the growing collection of open source GROVE transducers.