The design portion of a second term freshman course, ‘Introduction to Engineering II’, provides an overview of each of the disciplines within the College, and a representative, discipline-specific design lab. With only 2 hours of pre-lab lecture/preparation, and 3 hours in-lab time, providing the necessary theory and completing a meaningful lab is extremely challenging when the fundamental discipline-specific knowledge is still very limited. This Electrical Engineering lab requires students to modify a program to implement a microcontroller-based combination lock. It simulates a hotel room door lock, except that it uses a key pad instead of a swiped card. This paper investigates the design of the lab, its implementation, and feedback results.