Abstract Where Cartesian philosophy distinguishes the perceiving and perceptual mind from the body, phenomenology constitutes the experiential/experiencing body as the subject, giving rise to the affective potential of art. An immersive world of digital connections, smart cities and the Internet of Everything dramatises the centrality of relationship, the intertwining of Self and Other, in the lived environments of human experience. This article addresses the contextual, disciplinary and practical challenges encountered in developing an ambitious interactive public art project embedding SMART technology on the coastal fringes of Cardiff, the capital city of Wales (UK). It examines the processes and problems involved in delivering a stimulating aesthetic experience in and on a complex site, for a complex audience profile. It traces, in particular, the dependence of a multi-disciplinary project team on the theoretical and practical effects of affect in their ongoing effort to produce engaging, provocative, socially inclusive interactive public art, in and through human-centred design techniques.