This paper presents an educational experience in an initial course in feedback control. The purpose is to introduce the concepts of robust design not included in the regular curriculum. The problem of designing a controller for a simple mechanical system without knowing the true value of the parameters is proposed in a laboratory class. The task is performed on the real system with the aid of Computer-Aided Design freeware. The combination of practice and software tools encourages the development of autonomous learning and favours the apprehension of the concepts of uncertainty and robustness. A perception survey shows promising results indicating that the strategy of learning by doing is very well accepted by the students.