The original motivation:
Both Noelle and I are pretty active people and we dislike bringing our room keys with us when we’re out running. Additionally, on really busy days, I sometimes forget my keys and I have to call the RA to unlock the door. 😦 I thought it would be extremely useful if we had a way to unlock our locked door. This project was inspired by our good MechE friend Mike, who had a card reader secured to the outside of his door. When he swiped his Duke card, a servo would unlock his door. Given that I already had the chance to tinker with the Arduino LCD shield, I thought I could modify his door-lock idea and replace the card reader with an LCD shield that asks for a four-number code.