Abstract
Biomedical implantable devices in real-time telemetry applications offer many advantages to study and monitor physiologic parameters in human and animal bodies. As in power-constrained implantable devices, batteries and wires are two key issues that usually compromise their application. Inductive coupling is a well-established technology because it replaces simultaneously the wired connection and avoids the use of batteries. In stand-alone applications that requires total freedom of movements, this technology may present some constrains. On the other hand,very-low power electronics, advanced energy harvesting techniques and smaller implantable rechargeable batteries makes now possible the conception of fully autonomous implantable devices. This paper describes an activation circuit used to completely turn-off battery-powered implantable devices. In addition, it allows the reception of embedded commands, suitable for calibration and sensor selection purposes. Results from an experimental device to be used in a smart hip prosthesis telemetry system for loosening detection shows the usefulness of the proposed activation concept.

Abstract
A new software package for the incremental hole-drilling technique (IHD) is presented in connection with undergraduate mechanical engineering education. The main available technical residual stresses evaluation procedures for applying MID in isotropic materials are reviewed and have been included in the package, it has an easy-to-use, friendly interface, and can be used as a tool to teach the IHD technique or as a laboratory to study its applicability to real world problems. A set of exercises have been prepared, which are freely distributed to our students, in order to show the full potential of the package, but the students can also do simulations and experiments with their own data. (C) 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 351-362, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20225

Abstract
Ever since the first studies about biomedical implantable devices, the problem of how to energize them has stood out as both important and notoriously difficult to solve. In order to extend the lifetime of implants, it is imperative to develop power generators that are autonomous, safe and maintenance-free. Energy harvesting is a natural way of meeting these requirements. First, the energy source is theoretically everlasting, a fact that helps to guarantee the autonomy. Second, the energy is obtained from the environment of the application itself, contributing to its safety. Finally, a properly designed energy harvesting system is very unlikely to ever require maintenance. This paper follows this line and describes an electromagnetic power transducer that harvests electrical energy from the human gait and stores it. An efficient power management module uses the stored energy to energize the telemetric system of a smart hip prosthesis implant, enabling the early detection of loosening, the target application of this work. The system is able to extract a total 1912.5 mu J of usable energy under normal walking conditions.

Abstract
We present a nonlinear mathematical model for a low-size and micro-power vibrational energy harvester targeted to power smart prostheses and in particular hip prostheses. Constraints such as available volume, allowable total weight and energy transducer mechanism difficult the development of an optimal generator system, especially considering the low frequencies involved in the human gait. Since non-linear behavior often conducts to better experimental results than those obtained using linear models, a nonlinear model is being pursued to reduce the volume of the generator and maximize performance. By including the non-linear effects of magnetic levitation used to suspend the inertial mass, influence of friction and effects of inductor non-idealities, preliminary results indicate better generator's performance prediction which allows a more effective customization of the energy harvester. (C) 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.

Abstract
This paper describes a multi-purpose energy management system that can harvest energy from a multitude of power sources. In order to suffice power needs of a smart hip prosthesis, a prototype was built considering the use of two types of power sources: energy harvesting micro-power generators for intermittent implant electronics powering; wireless energy, by means of an activation system, responsible for, when needed, continuously powering the implant electronics and also configuring its mode of operation. Intermittently or continuously, it is now possible to energize more power demanding systems as the ones that uses a RF transceiver. The smart hip prosthesis can now become a wireless body sensor network node using LR-WPAN protocols such as Bluetooth low energy as is intended in this work. Preliminary results proved that is possible to energize a Bluetooth low energy module, for over 100 s, solely using the stored energy produced by one of the micro-power generators. (C) 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.

Abstract
This paper describes an improved micro-power electric generator where energy harvested from human movements is used as an everlasting mechanical energy source to suffice smart hip implant electronics power needs. Its architecture is designed so that the mechanical energy promotes the movement of a combination of magnets and a spring embedded inside a Teflon tube, used to reduce friction. The changing magnetic field induces current in two coils so that the output of the generator is the sum of their signals. The end result is like a double generator in one casing. Produced electrical energy is stored in an energy reservoir handed over to a power management module. Experimental results shows that energy harvested from human walking can be used as an effective power source for hip prosthesis implants. (C) 2010 Published by Elsevier Ltd.