論文アブストラクト：We are surrounded by a proliferation of connected devices performing increasingly complex data transactions. Traditional design methods tend to simplify or conceal this complexity to improve ease of use. However, the hidden nature of data is causing increasing discomfort. This paper presents BitBarista, a coffee machine designed to explore perceptions of data processes in the Internet of Things. BitBarista reveals social, environmental, qualitative and economic aspects of coffee supply chains. It allows people to choose a source of future coffee beans, situating their choices within the pool of decisions previously made. In doing so, it attempts to engage them in the transactions that are required to produce coffee. Initial studies of BitBarista with 42 participants reveal challenges of designing for connected systems, particularly in terms of perceptions of data gathering and sharing, as well as assumptions generated by current models of consumption. A discussion is followed by a series of suggestions for increasing positive attitudes towards data use in interactive systems.