Building a Distance Sensing Device


Class: BE209
Group: W4
Members: Gary Chang, Elizabeth Robinson, Chris Mullin, Tim Siropaides, Terry Huang

Date: December, 2002

Full Text

Introduction
People who are visually impaired face many difficulties in everyday life.  One such difficulty is moving from place to place, as their lack of vision prevents them from navigating around obstacles.  Without any assistance, the visually impaired people have no way of knowing if obstacles of any kind (walls, buildings, poles, etc.) are in their way.  The goal of this experiment is to produce a device that will signal to the visually impaired how far they are from certain objects.  More specifically, the goal is to build a portable device that can relate distances from certain obstacles into pitches whose frequencies are proportional to the distance from the object, and to test the limitations of this device.
To better understand the limitations of the device, a total of five tests will be performed.  Different colors in the world reflect light differently.  The frequency emitted by the device will be compared for distances from various colored pieces of paper, to determine how color affects the device.  When walking in the real world, a blind person will not approach everything from straight on (i.e. a 90 degree angle).  Thus, the frequency emitted by the device will be tested at different angles to determine what effect the angle has on the device.  The device must be usable at all times during both the day and the night, so the frequency emitted by the device will be measured in a dark room with the help of a flashlight, to determine if the device is still operational in a dark environment.  These three tests will provide a comprehensive understanding of the device, but they provide no practical information.  The fourth and final test will be to set up an obstacle course in a small hallway, and measure the time it takes for blindfolded subjects to walk through this course, both with and without the device, as well as the number of obstacles they bump into along the way.  With this data, both theoretical and practical, a conclusion about the real-life implications of this device can hopefully be made.