Abstract-This paper presents the evolution of an undergraduate microcontroller's course that uses Arduino as its main platform. In earlier versions of the course, it focused on teaching Arduino's framework and its interconnection to compatible hardware. This allowed rapid familiarization with the hardware and software, but students were losing the capability to design their own prototypes. So, we tried a different approach that still uses Arduino, but includes a deeper study of technical details to have more control on the device. This paper presents the first comprehensive analysis of these methodologies. The proposed course starts studying Arduino's platform as a tool to get familiar with the hardware and software interface. On the second part, students gain a deeper understanding of the Arduino framework, and are able to configure its main features. On the last part, students put the Arduino framework aside and focus on the microcontroller to learn the principal features of its architecture. We observed that the evolution of the course has helped to increase the student's skills and motivation.Keywords--Embedded systems, microcontrollers, Arduino, project-based learning. Abstract-This paper presents the evolution of an undergraduate microcontroller's course that uses Arduino as its main platform. In earlier versions of the course, it focused on teaching Arduino's framework and its interconnection to compatible hardware. This allowed rapid familiarization with the hardware and software, but students were losing the capability to design their own prototypes. So, we tried a different approach that still uses Arduino, but includes a deeper study of technical details to have more control on the device. This paper presents the first comprehensive analysis of these methodologies. The proposed course starts studying Arduino's platform as a tool to get familiar with the hardware and software interface. On the second part, students gain a deeper understanding of the Arduino framework, and are able to configure its main features. On the last part, students put the Arduino framework aside and focus on the microcontroller to learn the principal features of its architecture. We observed that the evolution of the course has helped to increase the student's skills and motivation.