The Wekinator is free, open source software originally created in 2009 by Rebecca Fiebrink. It allows anyone to use machine learning to build new musical instruments, gestural game controllers, computer vision or computer listening systems, and more.

System works with several inputs and outputs, managed by the wekinator.
Inputs could be sent from any real-time input, such as game controllers, webcam input, motion tracking, audio input, sensors connected to Arduino, etc. Outputs could be sent to any real-time process, such as music (Max/MSP, ChucK, PD, SuperCollider, Ableton/Max4Live…), animation (Processing, OpenFrameworks, …), games (Unity3D), robots or physical actuators (e.g. using Arduino), etc.

Here a quick walktrought of the process

and a screenshot

credits: wekinator.org

Since the wekinator is a single Java executable, work on any (compatible) platform.