International Journal of New Technology and Research (IJNTR) ISSN:2454-4116, Volume-1, Issue-6, October 2015 Pages 10-13 10 www.ijntr.org Abstract— This paper present the experimental design of an energy harvesting system using active materials for power generation from the shoe sole. The active material as PZT has been employed and modified to be appropriately embedded in the shoe sole. When the mechanical pressure is applied to the embedded shoe sole while walking would extract mechanical vibration energy and convert extracted energy to electrical energy directly from the piezoelectric structure inserted in shoe sole via a rectifier to a power processing system. The power processing system regulates the harvested electrical energy and accumulates the generated electrical energy to sufficient voltage level for powering portable electronic devices for later use. In this paper we show the simulation and experimental results of energy harvesting circuit and efficiency of the extracted ambient vibration energy by PZT in terms of electrical voltages during single step and continuous walking for a period of time. Index Terms— Ambient vibration energy, Energy Harvesting, PZT, shoe sole, power processing system, portable electronic devices and Tina software. I. INTRODUCTION Energy harvesting transforms green energy sources into usable electrical energy like solar energy, thermal energy, wind and vibration energy, etc. In the recent years micro power electronics and portable storage devices requires low power requirements for their operations and due to the existing characteristics of such devices the demand for energy harvesting from the surrounding environment increases drastically, due to the low power generation of these energy harvesters [1]. This technology is very attractive for low power portable electronic devices which include pacemakers, flashing LEDs at night, mobile phones and hearing aid devices [2, 3]. One of the most interesting sources for energy harvesting is surrounding environmental ambient vibrations. The sources used for energy harvesting are piezoelectric, electromagnetic, electrostatic, pyroelectric, photovoltaic and thermoelectric. For low power generation piezoelectric source is the best candidate for extracting energy from ambient vibrations. Another reason for using piezoelectric materials is its property to extract energy from ambient vibrations which are readily available from human walking. Piezoelectric energy harvesting is getting more attention due to the fact that it can provide the emergency source for powering low power portable electronic devices in the hilly areas, public places where rechargeable batteries cannot be powered. This wasted energy is captured by some means and that is called as energy harvesting. During the human motion there is the movement of various parts of the body generates Ashish Gupta, ECE, Chameli Devi Group of Institutions, Indore, India, Asharfilal Sharma, School of instrumentation, DAVV, Indore, India, vibrations and these vibration energy can be extracted easily by piezoelectric element into usable electrical energy [4]. The use of piezoelectric materials is feasible since they are much flexible and they can be used with minimal design changes in most of the applications. Heart rate meter and respiratory rate meter have approximately 3 J of energy consumption for one hour of operation. Ambient vibrations consist of a travelling wave on a solid material and it is often not possible to find a relative movement within the reach of a small energy harvester. The piezoelectric materials are attached to the locations where sensible mechanical vibration has to be coupled to the harvester by means of the inertia of a seismic mass. Fig. 1 shows a seismic mass connected to an energy harvester. The mass is also connected to the outside world by means of a suspension/damper system [5]. Fig.1 Equivalent model of a vibrating piezoelectric structure FUNDAMENTAL OF PIEZOELECTRIC MATERIAL The piezoelectric term comes from a Greek word piezein for pressure electricity. The piezoelectric effect exists in two domains; the first is the direct piezoelectric effect that describes the material‟s ability to transform mechanical strain into electrical charge, the second form is the converse effect, which is the ability to convert an applied electrical potential into mechanical strain energy. The direct piezoelectric effect is more suitable for sensor applications, whereas the converse piezoelectric effect is most of the times required for actuator applications [6]. The direct effect and the converse effect may be modeled by the following matrix equations: Direct Piezoelectric Effect: D = d. T + E T . E (1) Converse Piezoelectric Effect: S = s E . T + D t . E (2) Where D is the electric displacement vector, T is the stress vector, ε T is the dielectric permittivity matrix at constant mechanical stress, s E is the matrix of compliance coefficients at constant electric field strength, S is the strain vector, d is the piezoelectric constant matrix, and E is Piezoelectric Energy Harvesting via Shoe Sole Ashish Gupta, Asharfilal Sharma