The term `Internet of Things' (IoT), was coined in 1999 (Ashton et al., 2009), and has continued to grow under this heading since its conception with a number of subheadings developed (such as, the Industrial Internet of Things (IIoT)) to give further classification as the field has expanded. By 2014 the IoT was being considered as an industry in its own right, "with the potential to have a greater impact on society than the rst digital revolution" (Walport, 2014, p. 6). The Internet of Things is a growing industry spanning many different markets and sectors with worldwide device forecasts going from 9.7 billion in 2020 to over 29 billion in 2030 (Vailshery, 2022).
As the industry matures it is becoming much easier for businesses and individuals to create IoT products and to release them onto the market. Components and resources are more readily available and a range of supporting services have been developed. Connected devices can now be seen in virtually every business sector. However, there are many design challenges associated with IoT design that have not yet been addressed in the academic literature. For example, the embedded, long-term, infrastructural nature of the IoT presents a somewhat unique design space for practitioners. The many layers of products and services add complexity to the task of design, both for new product design (Lee et al., 2019b) and modification
of existing deployed systems. As embeddedness is core to the vision of ubiquitous computing it is important for research to move beyond the lab into real-world deployed settings (Fox et al., 2006). This is of particular importance to address theory practice gaps where research attempts to influence and inform interaction design. Investigating the existence and extent of a theory-practice gap requires a closer look at how interaction designers within the commercial world actually work, how their roles are
organised and what constitutes professional competence (Goodman et al., 2011).
The aim of the research in this thesis is to explore the challenges faced by design practitioners within the IoT industry and their methods of addressing them. This is with the intention of attending to the theory practice gap through provision of insights for the purpose of informing the creation of methods, practices and further academic research into the work of designing the IoT. The research was guided by the primary research question: 1) How do IoT related design team organise their work? which is addressed
through the secondary questions of: 2) What design challenges are being faced when designing for the IoT within a commercial context? 3) What design practices are being applied to IoT related design work within these settings, and how?
The findings reported here answer these research questions through the following contributions. 1) Identification of relational tensions within the process of IoT related design and demonstrations of practitioners methods of foregrounding them. 2) Demonstrations of the ways in which practitioners
maintain visibility over tensions and product service layers to situate design reasoning. In particular, generation and use of notions of elemental states as a form of infrastructuring work, which builds on previous discussions of infrastructural inversion (Bowker, 1994; Simonsen et al., 2020) and the use of decision trees as a form of user journey mapping (Endmann and Keßner, 2016). 3) Identification of additional roles and responsibilities of digital plumbing (Tolmie et al., 2010; Castelli et al., 2021) and data-work within the IoT design space (Fischer et al., 2017)
