The concept of tinkering is a central practice within research in the field of Human Computer Interaction, dealing with new interactive forms and technologies. In this thesis, tinkering is discussed not only as a practice for interaction design in general, but as an attitude that calls for a deeper reflection over research practices, knowledge generation and the recent movements in the direction of materials and materiality within the field. The presented research exemplifies practices and studies in relation to interactive technology through a number of projects, all revolving around the design and interaction with physical interactive artifacts. In particular, nearly all projects are focused around robotic artifacts for consumer settings. Three main contributions are presented in terms of studies, prototypes and concepts, together with a conceptual discussion around tinkering framed as an attitude within interaction design. The results from this research revolve around how grounding is achieved, partly through studies of existing interaction and partly through how tinkering-oriented activities generates knowledge in relation to design concepts, built prototypes and real world interaction.