A body area network for wearable health monitoring : conductive fabric garment utilizing DC-power-line carrier communication

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 112-116).Wearable computing applications are becoming increasingly present in our lives. Of the many wearable computing applications, wearable health monitoring may have the most potential to make a lasting positive impact. The ability to remotely monitor physiological signals such as respiration, motion, and temperature has benefits for populations such as elderly citizens, fitness professionals, and soldiers in the battlefield. To fully integrate wearable networks into a user's daily life, these systems must be minimally invasive and minimally intrusive. At the same time, such wearable networks require multiple sensors and electronic components to be mounted on the body. Unfortunately, typical off-the-shelf components of this nature are heavy, bulky, and don't integrate well with the human form. Thus, it is critical to figure out how best to minimize the physical and mental burden that these systems place on the user. To address these problems, we propose a new method of designing wearable health monitoring networks by combining electrically conductive fabrics and power-line communication technology. Electrically conductive fabrics are useful in that they feel and behave like normally worn clothing but also have the ability to transmit data and power.(cont.) To fully exploit the conductive fabric as a transmission medium, we also use power-line communication technology. Power-line communication allows for simultaneous power and data transmission over a shared medium. The use of these two technologies will allow us to significantly reduce the amount of metal cabling on the body and to reduce overall system bulk and weight. With this project, we design the DC-PLC system that will act as the physical layer of the architecture. Next, we construct a prototype body area network, and derive analytical models for predicting garment electrostatic and electro-dynamic properties using Maxwell's equations, and verify using empirical data and finite-element analysis. Finally, we will determine relevant rules and guidelines for the design and construction of such garments.by Eric R. Wade.Ph.D

Conductive Textiles and their use in Combat Wound Detection, Sensing, and Localization Applications

Conductive textiles, originally used for electromagnetic shielding purposes, have recently been utilized in body area network applications as fabric antennas and distributed sensors used to document and analyze kinematic movement, health vital signs, or haptic interactions. This thesis investigates the potential for using conductive textiles as a distributed sensor and integrated communication system component for use in combat wound detection, sensing, and localization applications. The goal of these proof-of-concept experiments is to provide a basis for robust system development which can expedite and direct the medical response team in the field. The combat wound detection system would have the capability of predicting the presence and location of cuts or tears within the conductive fabric as a realization of bullet or shrapnel penetration. Collected data, along with health vitals gathered from additional sensors, will then be wirelessly transmitted via integrated communication system components, to the appropriate medical response team. A distributed sensing method is developed to accurately predict the location and presence of textile penetrations. This method employs a Wheatstone bridge and multiplexing circuitry to probe a resistor network. Localized changes in resistance illustrate the presence and approximate location of cuts within the conductive textile. Additionally, this thesis builds upon manually defined textile antennas presented in literature by employing a laser cutting system to accurately define antenna dimensions. With this technique, a variety of antennas are developed for various purposes including large data transmission as would be expected from multi-sensor system integration. The fabrication technique also illustrates multilayer antenna development. To confirm simulation results, electrical parameters are extracted using a single-frequency resonance method. These parameters are used in the simulation and design of single-element and two-element wideband slot antennas as well as the design of a wideband monopole antenna. The monopole antenna is introduced to an indoor ultra-wideband (UWB) localization system to illustrate the capability of pinpointing the wearer of textile antennas for localization applications. A cavity-backed dog-bone slot antenna is developed to establish the ability to incorporate conductive vias by sewing conductive thread. This technique can be easily extrapolated to the development of textile substrate integrated waveguide (SIW) technologies

Wearable electromyography measurement system using cable-free network system on conductive fabric

金沢大学大学院自然科学研究科情報システムObjective: To solve the complicated wires and battery maintenance problems in the application of wearable computing for biomedical monitoring, the electromyography (EMG) measurement system using conductive fabric for power supply and electric shield for noise reduction is proposed. Material and methods: The basic cable-free network system using conductive fabric, named as "TextileNet" is developed. The conductive fabric has the function of electric shield for noise reduction in EMG measurement, and it enables the precise EMG measurement with wearable system. Results: The specifications of the developed prototype TextileNet system using wear with conductive fabric were communication speed of 9600 bit/s and power supply of 3 W for each device. The electric shield effect was evaluated for precise EMG measurement, and the shield efficacy of conductive fabric was estimated as high as that of shield room. Conclusions: TextileNet system solves both the problems of complicated wires and battery maintenance in wearable computing systems. Conductive fabric used in TextileNet system is also effective for precise EMG measurement as electric shield. The combination of TextileNet system and EMG measurement device will implement the cable-free, battery-free wearable EMG measurement system. © 2007 Elsevier B.V. All rights reserved

Communication and energy delivery architectures for personal medical devices

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 219-232).Advances in sensor technologies and integrated electronics are revolutionizing how humans access and receive healthcare. However, many envisioned wearable or implantable systems are not deployable in practice due to high energy consumption and anatomically-limited size constraints, necessitating large form-factors for external devices, or eventual surgical re-implantation procedures for in-vivo applications. Since communication and energy-management sub-systems often dominate the power budgets of personal biomedical devices, this thesis explores alternative usecases, system architectures, and circuit solutions to reduce their energy burden. For wearable applications, a system-on-chip is designed that both communicates and delivers power over an eTextiles network. The transmitter and receiver front-ends are at least an order of magnitude more efficient than conventional body-area networks. For implantable applications, two separate systems are proposed that avoid reimplantation requirements. The first system extracts energy from the endocochlear potential, an electrochemical gradient found naturally within the inner-ear of mammals, in order to power a wireless sensor. Since extractable energy levels are limited, novel sensing, communication, and energy management solutions are proposed that leverage duty-cycling to achieve enabling power consumptions that are at least an order of magnitude lower than previous work. Clinical measurements show the first system demonstrated to sustain itself with a mammalian-generated electrochemical potential operating as the only source of energy into the system. The second system leverages the essentially unlimited number of re-charge cycles offered by ultracapacitors. To ease patient usability, a rapid wireless capacitor charging architecture is proposed that employs a multi-tapped secondary inductive coil to provide charging times that are significantly faster than conventional approaches.by Patrick Philip Mercier.Ph.D