“Doorman” was a device I created as part of a team during my ENGS 21
(Introduction to Engineering) class at Dartmouth College. This device is
designed to retrofit dorm deadbolt locks and allowed them to be opened with a
key card or smartphone.
ENGS 21 is an introductory engineering class where students are challenged to
create a product that would improve life on campus. I worked as part of a group
of five students to design a system to alleviate some of the problems students
have with dorm security. Many students don’t lock their doors because they
don’t like carrying their keys with them or because they have lost their keys.
On the other hand, almost everyone carries their phone or school issued ID card
with them at all times. If these could be used to unlock dorms, students might
be more likely to lock their doors, preventing incidents of theft and vandalism.
Our prototype went through a number of iterations, starting with a foam core
mock-up. This version allowed us to brainstorm ways of interfacing with a
deadbolt, and how various components would interact.
We then designed and built a prototype out of laser cut plywood. We used this
material because it allowed us to quickly build complex designs, while using
very little material.
Our first wood prototype made us aware of some issues with the motor and belt
mountings, so we developed a second version that was successfully able to
manipulate a lock.
At this point, the control system consisted of an Arduino Uno, stepper motor
driver and magnetic card reader mounted on a breadboard outside of the frame of
the lock. We redesigned the electronics using an Arduino Pro Mini, so that they
would all fit on a perfboard within the device. We also designed a thermoformed
plastic case to hide and protect the internal components.
This video shows the final prototype in use on an actual dorm door.
This video shows me discussing the project at our final presentation.