This article analyzes sensory aspects of material politics in social movements, focusing on two police tools: evidence-collecting cameras and noise meters for protest surveillance. Through interviews with Korean political activists, this article examines the relationship between power and the senses in the material culture of Korean protests and asks why cameras and noise meters appeared in order to control contemporary peaceful protests in the 2000s. The use of cameras and noise meters in contemporary peaceful protests evidences the exercise of what Michel Foucault calls 'micro-power'. Building on material culture studies, this article also compares the visual power of cameras with the sonic power of noise meters, in terms of a wide variety of issues: the control of things versus words, impacts on protest size, differential effects on organizers and participants, and differences in timing regarding surveillance and punishment.