<p>There is a growing number of sensors, cameras and measuring devices in the public space. Why are they hanging on the lamp post? What are they measuring? And by whom? Those questions are relevant to the citizens to be assured that no private and sensitive data are collected without their approvement. At the same time the municipalities feel obligated to be transparent about the hanging devices to the inhabitants and provide a good working registration tool to the owners of the measuring devices. The sensor owners would also value the clarity about the process to register their devices and uniformity in the legislation if they plan to install their devices throughout more cities. We cannot forget about researchers, developers and data scientists who would highly appreciate the transparency about the measuring devices and the potential access to the data from the sensors.</p><p>A National Sensor Registry (SensRNet) seems to be the solution to answer the abovementioned questions. The registry would: provide transparency to the municipalities and citizens about the data collected by the devices and the purpose for collection; provide overview and insight into where sensors are placed in public space and who is the owner; allow sensor owners to register the devices in a uniform way; provide access to highly demanded data to utilize the smart city concept; act as a platform that provides transparent, safe and secure environment where citizens and entrepreneurs can get more information or make objections against the reason behind collecting data.</p>