This project aims at creating a user interface design pattern library for senior adults under the umbrella of the S4S (Smartphones for Seniors) project. The input for the project will build upon the knowledge gathered with the Smart Companion, a project for which a vast number of usability tests have already been performed and documented. The main focus of research will be on user interface design patterns. These patterns should be structured, organized and developed in a way that allow for easy access through a simple Web application, which clients can access to guide their design and development processes. An interaction design pattern is defined as an effective solution to a recurring problem. The particular problem being addressed, in this work, has to do with issues related to touch-based interaction for senior adults. The literature review suggests that these might not be adequate for this particular audience, and therefore we propose creating a new user-defined approach to sets of gestures. This project intends to enable older adults to actively participate in the specification of the gestures they are expected to be able to use when interacting with touch-surfaces. The patterns will appear as a result of testing and analyzing these user-defined gestures against commercially available ones. We expect to uncover a more adequate set of gestures and document them in pattern form, in order to facilitate their adoption by interaction designers.