In the Master's of Telecommunication Engineering program at the University of Deusto, Spain, courses in communication circuit design, electronic instrumentation, advanced systems for signal processing and radiocommunication systems allow students to acquire concepts crucial to the fields of electronics and communication. During the educational project presented in this paper, students build a continuous-wave frequency-modulation (CWFM) Doppler radar system from components as simple as ordinary cocoa cans and common electronics components placed on a breadboard without any soldering. One of the goals of the project is to stimulate students' interest in building an entire, completely functional communication system that integrates the knowledge acquired in the various courses and whose functioning they can check in real scenarios. This paper describes this learning project and the ways in which it helps students understand and connect all the concepts that underlie a fully operative communications system, thus meeting the competencies and learning outcomes of the courses involved in the project.