Purpose - This paper aims to present the design of a modular robot with 3D-printing technology. Design/methodology/approach - The robot consists of a number of autonomous modules coupled by magnetic interfaces. Each module combines 3D-printed mechanical parts with widely available standard electronic components, including a microcontroller and a single servo actuator. The mechanical and electrical connection is provided by a single set of magnets which apply the physical force between the modules and at the same time serve as wires for power and communication. Findings - The PMR is a full-featured robotic device, well integrated into a simulation framework, capable to execute common locomotion patterns but still extremely affordable (approximately 25€/module). Furthermore, the design is easy to extend and replicate for other research and education groups. Originality/value - This paper explores a novel approach of connecting devices in a complex way by utilizing very simple magnetic parts. A second focus lies on the concept of closely integrating simulation and hardware development, blurring the edge between digital and physical word.