A new hybrid infrared-ultrasonic electronic travel aids for blind people

The work presented here concerns the study of a new electronic travel aids for visual impaired and blind people for which the white cane represents, still today, the most widely used tool. The new system that we are going to present in this work is composed of two infrared sensors, an ultrasonic one, a microcontroller (to manage the input signals and take decisions) and four vibrating motors used to give signals to the user when an obstacles is intercepted. All these components are integrated in a belt that is easy to dress and is not very wearable. Here we also show all the characteristics of the sensors, their calibrating curves, the sensors spots and main noise in order to have a completely knowledge of these devices and to better understand their possible use. An energy consumption is studied in order to understand the autonomy of our device, being it portable. A geometric analysis is done to find the correct angular position of the sensor that influences the speed of response and the proper functioning of the entire system. Three different filters are implemented and compared in order to clean the input signals characterized by great noise due to the oscillation of the user during walk. Finally validation tests are made to check the ability of the device to intercept obstacles and to advice the user on time. (C) 2013 Elsevier B.V. All rights reserved.