Replacing Free-Ranging Robots with Alternative Mobile Nodes

A wide range of mobile devices, e.g., wireless sensor nodes, RFID tags and smartphones, gradually coalesces into the Internet of Things (IoT). Debugging and optimizing such systems is challenging and necessary to realize the foreseen vision. In this paper, we describe our endeavor to build and adapt a testbed enabling the analysis of different scenarios involving mobile elements. Instead of creating a versatile but expansive testbed based on free-ranging robots, we developed a set of specialized components based on model trains. Our goal was to save costs while providing repeatable and accurate experiments where the movement of the tested devices is not provided by battery powered platforms. %This endeavor did not come without trouble and more realistic requirements changed our planned path. The contribution of this paper is to describe the iterative design and realization process for each testbed component and to quantify the trade-offs between different approaches. We discuss how our solutions evolved due to the constraints of the real experiments that were carried out on the various instances of the testbed, with a particular focus on the experience we acquired in the process and the lessons we have learned along the way.