This paper presents an empirical approach to designing and deploying technologies to support visitor activities in exhibition spaces. Specifically, we focus on the concept of "assembly" and how it was extended and applied to develop an interactive installation for an open-air museum. We argue that this approach to designing for a meaningful visitor experience is particularly suited to open-air visit scenarios; we describe how we have extended the approach and applied it, detailing the resulting multi-device installation that was deployed on site, and presenting some reflections on the usefulness of the assembly concept. Copyright 2011 ACM.