André P. Catarino

Study of vital sign monitoring with textile sensors in swimming pool environment

This paper presents the results of a series of experiments aiming at the optimisation of vital sign monitoring using textile electrodes to be used in a swimsuit. The swimsuit will integrate sensors for the measurement of several physiological and biomechanical signals; this paper will focus on ECG and respiratory movement analysis. The data obtained is mainly intended to provide tools for evaluation of high-performance swimmers, although applications can be derived for leisure sports and other situations. A comparison between electrodes based on different materials and structures, behaviour in dry and wet environments, as well as the behaviour in different extension states, will be presented. The influence of movement on the signal quality, both by the muscular electrical signals as well as by the displacement of the electrodes, will be discussed. The final objective is the integration of the electrodes in the swimsuit by knitting them directly in the suits fabric in a seamless knitting machine.

Monitoring knitting process through yarn input tension: new developments

In the knitting industry, the appearance of faults during production is an issue of major concern, since it affects quality and productivity. There exist a set of instruments and accessories for detecting faults and avoid as much as possible the generation of defects, however they are stand-alone systems and there is not an integrated information for the technician about the knitting process, capable of helping him in the maintenance and repair of the knitting machine. The yarn input tension, due to its nature, constitutes a valuable way of diagnosing the functioning of the machine. This paper presents the research conducted in this area at this university by presenting a redesigned acquisition system in order to acquire and analyse the measurement of the yarn input tension, towards a system capable of effectively detect faults and abnormalities during the production of weft knitted fabric.

A smart wearable system for sudden infant death syndrome monitoring

Sudden Infant Death Syndrome (SIDS) is one of the major causes of death among infants during their sleep. To increase the safety of the infants, we matched different emergent research fields for the development of Baby Night Watch. This Smart Wearable System (SWS), developed under the context of the European Texas Instruments Innovation Challenge (TIIC) 2015, is composed by the following elements: a Wearable IoT Device, a Gateway and the H Medical Interface. The Wearable IoT Device is a wireless sensor node integrated in a Chest Belt, and it has the capacity to monitor the following parameters: body temperature, heart and breathing rates and body position. After a minimal data processing, this set of information is sent to the Gateway, via ZigBee technology, and it is accessible to the user through the H Medical Interface. If a critical event occurs, the device will trigger an alarm, visible and audible in the proximity, and sends a distress message to a mobile application. The Baby Night Watch is an important tool for medical studies, since it allows the visualization of previous physiological data and export it to different types of datasets. Experimental tests have proven that the SWS has the potential to identify situations that could be potentially life-threatening for an infant.

Health monitoring using textile sensors and electrodes: An overview and integration of technologies

This paper gives an overview of technologies and results of integration and test of textile integrated sensors and electrodes for monitoring of biosignals (electrocardiographic - ECG and electromyographic - EMG), breathing and moisture. Using a seamless jacquard knitting machine, it is possible to integrate these sensors and electrodes directly into the fabrics, which can then be used in clothing for monitoring of elderly people, in sports or in hazardous occupations. The total integration of the sensing elements and connections into the garment presents great advantages in physical as well as psychological comfort of the user. It has been shown that the measurements are of adequate quality for most of the applications. In some cases, as is the case of ECG and EMG, signals acquired are similar to those obtained using conventional electrodes.

Investigating the effect of moisture on the thermal comfort properties of functional elastic fabrics

Thermo-physiological wear comfort is mainly determined by the thermal and moisture performance of clothing. Moreover, moisture is widely recognized as one of the most important factors contributing to discomfort sensations. Functional yarns with a thermo-regulating effect improve thermal and moisture performance of fabrics, but the integration of elastic yarns into the fabric structure can impair thermo-physiological wear comfort. The goal of this research was to compare, in dry and wet states, the thermal comfort properties of elastic knitted fabrics with thermo-regulating yarns, namely Viscose Outlast® and Polyester Coolmax® to better understand thermal behavioral changes due to moisture content of the fabrics. Surface moisture transfer between the fabrics and a wet skin was also assessed and enabled to evaluate the level of the unpleasant contact feeling. Air permeability that is related to the thermal behavior was also investigated. The results obtained showed that at 22% moisture content, which simulates a sweating sensation, the change in thermal properties is similar for both fabrics. Above the ‘sweating sensation’ moisture, significant differences on the thermal properties with the moisture content were registered between fabrics, Outlast® fabric being more prone to thermal properties changes due to moisture uptake than the Coolmax® one. When worn in conditions of wet skin, the unpleasant cool feeling increased for both fabrics, but the effect is more pronounced for Outlast® fabric.

Treat me well: Affective and physiological feedback for wheelchair users

This work reports a electrocardiograph and skin conductivity hardware architecture, based on E-textile electrodes, attached to a wheelchair for affective and physiological computing. Appropriate conditioning circuits and a microcontroller platform that performs acquisition, primary processing, and communication using Bluetooth were designed and implemented. To increase the accuracy and repeatability of the skin conductivity measuring channel, force measurement sensors were attached to the system certifying measuring contact force on the electrode level. Advanced processing including R-wave peak detector, adaptive filtering and autonomic nervous system analysis based on wavelets transform was designed and implemented on a server. A central design of affective recognition and biofeedback system is described.

Low cost sensor for the measurement of yarn input tension on knitting machines

The production of weft knitted fabric demands a continuous monitoring of the yarn forces directly involved in the knitting process. This monitoring prevents the occurrence of unthreaded yarns due to yarn break, and thus avoids the decrease on productivity. On the other hand, more information concerning the knitting process is desirable, because it allows the evaluation of possible future malfunctions and detection of faults. The classical device which is usually used to accomplish the first task does not have the necessary technology to accomplish the second task. The purpose of this paper is to present research that is being carried out to develop a different sensor device, capable of complying with both objectives and thus successfully replace the present system, which is used solely to detect lack or exceeding force applied to the yarn. Furthermore, the solution suggested is a low cost one, allowing its installation in every feeder as the present solution. Some considerations are made concerning the problems that this approach present and the dynamical behaviour for different configurations of the system is discussed.

Localization and Positioning Systems for Emergency Responders: A Survey

The availability of a reliable and accurate indoor positioning system (IPS) for emergency responders during on-duty missions is regarded as an essential tool to improve situational awareness of both the emergency responders and the incident commander. This tool would facilitate the mission planning, coordination, and accomplishment, as well as decrease the number of on-duty deaths. Due to the absence of global positioning system signal in indoor environments, many other signals and sensors have been proposed for indoor usage. However, the challenging scenarios faced by emergency responders imply explicit restrictions and requirements on the design of an IPS, making the use of some technologies, techniques, and methods inadequate on these scenarios. This survey identifies the specific requirements of an IPS for emergency responders and provides a tutorial coverage of the localization techniques and methods, highlighting the pros and cons of their use. Then, the existing IPSs specifically developed for emergency scenarios are reviewed and compared with a focus on the design choices, requirements, and additional features. By doing so, an overview of current IPS schemes as well as their performance is given. Finally, we discuss the main issues of the existing IPSs and some future directions.

Integration and Embedding of Vital Signs Sensors and Other Devices into Textiles

The development of ubiquitous vital sign monitoring has become a very up-to-date research theme for many academics and industrial companies in the last years. With new materials and integration techniques, it is possible to implement vital sign monitoring in an economic manner, directly into textile products. This unobtrusive presence of sensors is especially important for the monitoring of children or elderly people. This paper focuses on two aspects of sensor integration: Integration of off-the-shelf electronic components, and the use of the textile material itself as sensor, or in general as an electrically active element presenting some exploratory work in the integration of electronic devices into textiles. The main objective was to reproduce and improve on previous work presented by other authors, and foster possibilities of developing garments for vital sign monitoring with immediate industrial and economic feasibility. The use of standard production techniques to produce textile-based sensors, easily integrated into garments and with mass-market potential, is one of the important motivations for this work.

Wearable biopotential measurement using the TI ADS1198 analog front-end and textile electrodes

The development of mobile systems for monitoring bioelectric signals outside a hospital environment involves many challenges that do not arise when it is in a controlled environment, like a hospital. The dimensions of these systems are an important factor to consider in order to facilitate their use without interfering with the daily activities of individuals. The purpose of this work is the implementation of a single-supply battery-powered, low power ECG/EMG signal monitoring system based on the ADS1198 Analog Front-End from Texas Instruments. The system was designed to acquire ECG signals from three electrodes using the integrated Right-Leg-Drive (RLD) circuit from the ADS1198. The developed analog front-end was connected for testing purposes through the SPI interface to a NI-USB 8451 board and signals were acquired using LabVIEW. The circuit was tested in several situations and proved to provide high quality signals using textile integrated electrodes and conventional disposable gel electrodes.