This paper reports our experience in developing a team-based project activity to promote engineering programs among secondary school students. The aim of the activity is to increase the interest of students for science and technology in general, but also to promote engineering skills, capabilities and values, leading to attract more secondary school students to enrollment for engineering programs. Simple theoretical concepts are illustrated through hands-on experimentation. To achieve this goal, the students build a Remotely Operated Underwater Robot in a 2½-day workshop. The robot is built using low-cost materials and the students customize their own design over the different phases of the workshop. Once the activity is completed, every team understands that with teamwork, effort and a good working strategy, every problem can be overcome. At the end of the activity, a survey is conducted through an assessment survey questionnaire which reflects different aspects related with the development of the activity and the degree to which learning of its different facets has been achieved. The responses and feedback from students serve not only to evaluate the workshop, but also as feedback for future fine-tuning of the different phases as pedagogical learning tools.