OpenCare prototypes a community-driven model of addressing social and health care, and explore its implications at scale. It draws on three elements: advances in collective intelligence research, to lend coherence and summarize large-scale online debates; advances in digital fabrication and cheap-and-open hardware technology; and the rise of a global hacker community, willing and able to look for solutions to care problems. We explore the potential of this approach to deliver innovative, human-centric care solutions that combine the low bureaucratization and low overhead of communities with the scientific knowledge and technical skills associated to state- and market-provided professional care. OpenCare orchestrates an open-to-all, community-driven process for addressing care issues, recruiting its participants from existing communities innovating at the edge of society (among others, hackers, artists, activists, designers). This entails the complete design cycle of sensemaking => selection of a problem-solution pair => prototype => testing => evaluation at scale; each step of the cycle will be radically open, with the debate happening online and the fabrication happening in hackerspaces and fully documented. We release open data and deploy onto them state-of-the-art analytical tools for collective intelligence: online ethnography and social network analysis. We integrate these two approaches into a semantic edges analysis approach. We expect two main types of impact. The first: contributing to a better understanding of how to deploy the collective intelligence of smart communities onto sustainability problems. The second: contributing to the debate on reforming care provision in Europe by exploring how community-driven care services might integrate in the existing European care policy landscape. OpenCare is delivered by a diverse consortium drawn from Europe’s best universities and the grassroots hacker community.