Abstract

There are situations where the opening of doors, drawers and other compartments becomes unviable for reasons of hygiene, contamination or simply by not being available to use hands, as in the case of people with immobilized or disabled arms which prevent this type of movement. Systems that operate by voice commands can be very useful in these cases, and with the current technology available it is possible to develop a system with relatively low cost and that can be accommodated in small spaces. The present work presents the development of an embedded system capable of capturing a numeric password spoken by the user, analyze this password and compare it with a predefined password to decide whether or not to open a specially designed lock. The software of the embedded system is able to capture the ambient sound through a microphone, to process it in real time and, with the aid of an Artificial Neural Network (ANN) of the Multilayer Perceptron type, interpret the numerical sequence spoken by the user in order to verify if this sequence matches the previously programmed password. In this version, the system is able to interpret ten digits in Portuguese language (“zero” (zero), “um” (one), “dois” (two), “três” (three), “quatro” (four), “cinco” (five), “seis” (six), “sete” (seven), “oito” (eight), and “nove” (nine)), but can be expanded to interpret variations of the same, such as “meia” (half a dozen), or higher numbers such as “dez” (ten), “onze” (eleven), and so on. In order to train the ANN, a database was created containing the locutions of the selected numbers. For the construction of this base, the utterances of the numbers were recorded by a group of 50 volunteers, including men, women and children.

Keywords

digital signal processing, artificial neural networks, speech recognition