Prototyping of a Sign Language Robotic Hand Using Local Materials

Abstract

People living with disability constitute a significant percentage of the world population. For many people with disabilities, assistance and support are prerequisites for participating in societal activities. This research work developed a hardware prototype of a robotic hand for sign language communication with persons living with hard of hearing disability (deaf and/or dumb). The prototype has three basic modules: input unit, control unit, and the robotic hand. The input unit is designed as an Android-based mobile application with speech recognition capabilities while the control unit is an ATMEGA 2560 microcontroller board. The robotic hand is constructed using locally available materials (bathroom slippers, expandable rubber, straw pipe, and tiny rope) together with three servo motors and designed to look and perform movements similar to a human hand. The prototype was evaluated quantitatively in terms of empirical accuracy and response time. It was also evaluated qualitatively by thirty-five (35) users, including two sign language experts, who completed questionnaires to rate the prototype on a 5-point Likert scale in terms of five parameters: functionality, reliability, ease of use, efficiency, and portability. An accuracy of 78.43% with an average response time of 2 seconds was obtained from empirical experiments. Statistical analysis of user responses showed that 97%, 68%, 77%, 80%, and 83% of users rated the system as above average for functionality, reliability, ease of use, efficiency, and portability, respectively. The robotic hand effectively communicates American Sign Language, which includes English alphabets, numbers (1-9), and some selected common words, which can be demonstrated with a single hand for hard of hearing persons. The prototype can be improved by extending the single robotic hand to a full robotic body with two hands.