International Journal of Advanced Engineering Research and Science (IJAERS) Peer-Reviewed Journal ISSN: 2349-6495(P) | 2456-1908(O) Vol-9, Issue-12; Dec, 2022 Journal Home Page Available: https://ijaers.com/ Article DOI: https://dx.doi.org/10.22161/ijaers.912.44 www.ijaers.com Page | 400 Footstep Classification Methodology using Piezoelectric Sensors Embedded in Insole Cláudio Gonçalves 1 , Carlos Moreira 2 , Deolinda Ferreira 3 , Edivan Neves 4 , Larissa Bacelar 5 , Andreza Mourão 6 1 Coordination of Electrical Engineering, State University of Amazonas, Brazil 2 Coordination of Mechanical Engineering, State University of Amazonas, Brazil 3 Center for Higher Studies of Itacoatiara, State University of Amazonas, Brazil 4 Coordination of Electronic Engineering, State University of Amazonas, Brazil 5 Center for Higher Studies of Itacoatiara, State University of Amazonas, Brazil 6 Higher School of Technology, State University of Amazonas, Brazil Received: 22 Nov 2022, Receive in revised form: 15 Dec 2022, Accepted: 22 Dec 2022, Available online: 29 Dec 2022 ©2022 The Author(s). Published by AI Publication. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/) Keywords—Smart insole, piezoelectric sensor, foot posture, footstep types. Abstract— This article presents a proposal for a methodology to classify the types of steps, using piezoelectric sensors embedded in an ethylene-vinyl acetate (EVA) insole, configuring a low-cost intelligent insole. From a few steps or a walk by the user, the electrical signals generated by the piezoelectric sensors are measured or stored for later treatment and analysis. The steps of the proposed methodology were applied step by step in tests carried out to classify the types of footsteps of male and female users, who used the intelligent insoles built into running shoes. The proposed methodology was also implemented in a computational code that was applied to classify the types of steps in the performed tests. The step classification results were satisfactory, compared with the specialized literature. It should be noted that the classification obtained from the application of the methodology is a suggestion of the type of footfall from an engineering point of view, and the result should be evaluated by a specialized health professional. I. INTRODUCTION Daily walking, the need to stand for a long period of time, performing physical activity, combined with the person's weight, demand energy consumption and great physical effort. In humans, the feet are of fundamental importance in locomotion, weight support and body balance. The basic mechanics of moving the foot's center of mass during walking or running are similar in mammals of different body sizes, but whereas most mammals contact the ground only with their fingers or the tips of their toes, humans and great apes are plantigrade, bringing the whole foot down, including the heel, as shown in the illustration of the human foot in Fig. 1 [1]. When starting the displacement, the main movements of the foot, shown in the lower part of Fig. 1, are: touch of the hindfoot on the ground (heel), followed, almost immediately, with the sole of the foot (plantar fascia) in a flat position on the ground supporting the body on the midfoot and, finally, the forefoot supporting the body, lifting the heel and levering the toes. Recent experimental studies show that human foot posture has important biomechanical implications on foot strike and thrust during walking and running. In general, the human foot model used for studies focuses on three major kinematic challenges of walking and running: (1) how the foot deals with impact forces when the lower extremity initially collides with the ground; (2) how the foot creates propulsive leverage for propulsion and (3) how the foot stores and releases elastic energy during running [1]. For a better analysis of plantar pressures, the sole of the foot can be divided into 15 anatomical areas, as shown in Fig. 2 [2], in which the heel corresponds to areas 1 to 3, the midfoot to areas 4 and 5, the metatarsus to areas 6 to 10 and the toes to