Problem Overview

We set out to design an improved solution to the problem that the lights in dorm rooms and offices are often left on when no one is present. Currently, there is no solution to this problem in our university's dormitories, and the solution in offices is a motion-sensing switch which is inadequate and annoying. These sensors constantly turn the lights off despite the presence of a person in the room who is sitting motionless at a desk. Our solution will successfully address the problem for both types of rooms.

Project Goal

The goal of our project is to create a light switch that will eliminate the waste of energy that occurs when room lights are needlessly left on in dormitories and school offices.

What is entailed?

We propose a design that will allow users to place their NAU ID (used to gain access to all NAU campus buildings) in a tray located on faceplate of the switch. When reading the presence of a valid card in the tray, the switch will function as any ordinary light switch. However, when no valid card is present, the lights will have limited functionality and will only remain on for short duration of time. This ensures that room lights cannot be left on unnecessarily for a long period of time.

Key Requirements & Specifications

Our solution must be able to replace any existing light switch at Northern Arizona University. The device must use only the existing in-wall wiring and fit within a standard electrical box. The cost of the device must be low enough that the monetary savings offset the total cost of the system.

System Diagram

This flowchart details the operation of our solution. The red arrows depict the normal operation of the switch turning the lights on and off. When the lights are on, the device will check for an NAU ID every 15 seconds. If an ID is found, the lights will remain on, and the verification will repeat every 15 seconds (shown with the yellow arrows). If no ID is found, the system will turn itself off (shown with the white arrow). From the off state, the lights can be turned back on, using the switch and the process will begin again.

System depiction


Northern Arizona University

We would like to thank Julie Heynssens for sponsoring our project.

Site last edited: February 17, 2016