The current project provides a practical interaction concept based on thumb-index movements to support ubiquitous computing using the example of a smart watch. Smart watches include particularly small screens which makes it difficult to navigate properly through menu options. In her master thesis, our student designed a working prototype and carried out user tests to evaluate the interface for intuitive and single-handed interaction. Results indicate longer task processing on basis of the thumb-index technique compared to a two-handed approach. Technical improvement and individual practice should further improve the outcome and fully exploit the advantages of single-handed smart watch usage.