The Portable Gestural Interface PyGmI, which we implemented, is a smart tool to interact with a system via simple hand gestures. The user wears some color markers on his fingers and a webcam on his chest. The implemented prototype permits to visualize and navigate into presentation files, thanks to a tiny projector fixed on the user's belt. The gesture recognition uses color segmentation, tracking and the Gesture and Activity Recognition Toolkit GART. This article presents PyGmI, its setup, the designed gestures, the recognition modules, an application using it and finally an evaluation.