Research on smart urbanism predominantly focusses on the production of digital knowledge. In response, this paper probes the potential and limitations of digital devices producing the kinds of knowledge needed for governing urban environments. Based on four case studies in Europe, the paper investigates what kinds of knowledge become privileged and what kinds of knowledge get overlooked when digital devices are deployed to inform urban governance. We find that non-digital knowledges are easily eclipsed, yet remain vital to effective and inclusive urban environmental governance. Our findings suggest that digital technologies need to be developed in ways that are attentive towards the different kinds of knowledge (digital and non-digital) that may be necessary for effective and inclusive urban governance. This holds for the knowledges that are used to develop digital devices and the knowledges intended to be generated through them, as well as openness towards unanticipated or overlooked knowledges that still matter.