This paper presents a multidisciplinary problem-based learning (PBL) project consisting of the development of a robot arm prototype and the implementation of its control system. The project is carried out as part of Industrial Informatics (II), a compulsory third-year course in the Automation and Electronic Engineering (AEE) degree program at the School of Engineering at Universitat Polite`cnica de Vale`ncia, Vale`ncia, Spain. The robot arm is a low-cost prototype, initially controlled with a joystick. The aim of the project is, first, to design and implement a full control system for the robot, including the necessary circuitry for microcomputer (ARM Cortex)-based control and, second, to pit the designed robot in competition against other students' robots. Incorporation of multidisciplinary PBL required changes in the organization of the course, which features various learning activities and their continuous evaluation; it also required knowledge of five other courses in the AEE program. PBL methodology is compared to a traditional method; the results obtained proved highly satisfactory. Moreover, the PBL robotic experience was highly rated by some 900 students.