Showing papers by "Tom Torfs published in 2008"

Human++: From technology to emerging health monitoring concepts

Abstract: This paper gives an overview of the recent results from the Human++ research program, which targets the realization of miniaturized, intelligent and autonomous wireless sensor nodes for body area networks. It combines expertise in micro-power harvesting techniques, ultra-low-power radio, ultra-low-power DSP and sensors and actuators. This paper illustrates how technological breakthroughs in these areas lead to the emergence of new health monitoring concepts.

Wearable Autonomous Wireless Electro-encephalography System Fully Powered by Human Body Heat

Abstract: A wearable, wireless 2-channel electro-encephalography (EEG) system has been realized which functions fully autonomously, without any batteries. It is fully powered by human body heat using a thermo-electric generator which can produce over 2 mW at 23degC. It uses two of IMECpsilas ultra-low power biopotential electronics chips to record high-quality EEG signals. The whole system consumes only 0.8 mW, while sampling and transmitting 2 channels of 12-bit EEG data continuously at 256 Hz. Previous work has shown body-heat powered sensors such as a wireless temperature sensor or pulse oximeter with a low transmission duty cycle, but never before a continuously acquiring and transmitting system with complete power autonomy has been demonstrated.

The NeuroProbes project: A concept for electronic depth control

Abstract: The European project NeuroProbes has introduced a new methodology to allow the fine positioning of electrodes within an implantable probe with respect to individual neurons. In this approach, probes are built with a very large number of electrodes which are electronically selectable. This feature is implemented thanks to the modular approach adopted in NeuroProbes, which will allow the implementation of integrated electronics both along the probe shaft and on the array backbone.

Wearable self-powered wireless devices with thermoelectric energy scavengers

Abstract: The wearable wireless sensors powered with human body heat, which have been developed at IMEC and Holst Centre starting 2004, demonstrated that the power obtainable on the human body is large enough to power practical applications. The improving performance characteristics of the thermoelectric generators (TEGs) on human skin were accompanied by the multi-fold reduction of the power consumption used by the electronics. Such matching of the power consumed to the produced one allowed the first medical device, a wireless pulse oximeter, with no battery in it. In this work, a more complex device, the wireless 2-channel EEG system, has been developed and tested. On one hand, the TEG in this system is the most powerful one among the TEGs fabricated to the moment: at 23 deg C, it produces over 2 mW at about 1.8-2 V. On the other hand, low power both electronics and biopotential readout ASIC allow operation of the EEG system at 0.8 mW consumption, so that the TEG has obvious power reserve to supply energy at higher ambient temperatures if necessary. The second device presented in this work is a wrist TEG, the first device operating at the theoretical limit of power production on man, which at 22 deg C is about 25 muW/cm2 (depends on thickness of a TEG) at a thermoelectric figure-of-merit ZT of 0.85. This device has been designed to answer the questions: (1) how much power can be produced on man in a real life, especially, in hot weather, and (2) what is the maximal ambient temperature at which the body-powered devices can work. The related sensor has been fabricated to measure and transmit the data to a laptop.

Wireless Vestibular Evoked Myogenic Potentials System

Abstract: Vestibular Evoked Myogenic Potentials (VEMPs) is a technique that can provide useful information in diagnosing certain balance disorders. Existing commercial VEMP testing systems are cabled systems, which impede certain experiments, particularly those that involve motion and rotation of the patient. This paper presents an autonomous wireless system to record VEMPs. The system uses IMEC's 60 muW 60 nV/radicHz biopotential readout front-end to extract the electromyogram (EMG). It uses IMEC's low-power processing and wireless platform to perform all signal processing locally, significantly reducing the amount of wireless data transmission. The system also implements a low-power audio synthesizer and an amplifier to create the necessary audio or vibration stimuli that are applied to the patient. The system can perform 1000 measurements on 2 AA batteries.