On the feasibility of noncontact ECG measurements

“© © 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”The article by Kranjec et al. [1], “Novel methods of noncontact heart rate measurement: A feasibility study” is interesting and informative as it compares different contactless methods for heart rate detection. Nevertheless, the use of the term “capacitively coupled ECG” (CCECG) in the article is confusing and may mislead readers. That article studies the feasibility of four noncontact methods for heart rate measurement, which are classified in two groups: “the methods measuring electromagnetic energy generated by the bioelectrical activity within the cardiac muscle (referred to as direct methods), and the methods measuring displacement of a part of the subject’s body caused by the periodic physical contractions of the heart (referred to as indirect methods). The first group is represented by a measuring device which detects changes in surrounding electric field...” [sic]. Later on, this device is described in [1] as being based on “capacitively coupled electrodes” and hence termed “CCECG Measuring Device.” The electrodes are two 48-cm2 metal plates placed side by side (see [1, Fig. 3]) placed at distances from 5 to 60 cm from the chest.Peer ReviewedPostprint (author's final draft

Proyecto MyGait: monitorización continua de los pacientes de parkinson

Las plantillas inteligentes son capaces de aplicar una vibración rítmica en episodios de congelación de la marcha. La información objetiva de MyGait ayuda a personalizar con precisión el tratamiento y maximizar sus efectos.Postprint (published version

A hands-on approach to differential circuit measurements

Electronic engineering is showing a definite trend towards differential circuits. However, most measurement instruments are single-ended. Consequently, engineering graduates often lack the skills to perform correct differential measurements. This paper describes the theoretical background, development and limitations of three experiments that help students to gain insight into differential measurements and the origin and consequences of a low common-mode rejection ratio. The experiments require only common equipment and suit both electrical and non-electrical engineering students.Peer Reviewe

Low-power direct resistive sensor-to-microcontroller interfaces

“© © 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.”This paper analyzes the energy consumption of direct interface circuits where the data conversion of a resistive sensor is performed by a direct connection to a set of digital ports of a microcontroller (µC). The causes of energy consumption as well as their relation to the measurement specifications in terms of uncertainty are analyzed. This analysis yields a tradeoff between energy consumption and measurement uncertainty, which sets a design procedure focused on achieving the lowest energy consumption for a given uncertainty and a measuring range. Together with this analysis, a novel experimental setup is proposed that allows one to measure the µC’s timer quantization uncertainty. An application example is shown where the design procedure is applied. The experimental results fairly fit the theoretical analysis, yielding only 5 µJ to achieve nine effective number of bits (ENOB) in a measuring range from 1 to 1.38 k. With the same ENOB, the energy is reduced to 1.9 µJ when the measurement limits are changed to 100 and 138 k.Peer ReviewedPostprint (published version

Micro air vehicles energy transportation for a wireless power transfer system

The aim of this work is to demonstrate the feasibility use of an Micro air vehicles (MAV) in order to power wirelessly an electric system, for example, a sensor network, using low-cost and open-source elements. To achieve this objective, an inductive system has been modelled and validated to power wirelessly a sensor node using a Crazyflie 2.0 as MAV. The design of the inductive system must be small and light enough to fulfil the requirements of the Crazyflie. An inductive model based on two resonant coils is presented. Several coils are defined to be tested using the most suitable resonant configuration. Measurements are performed to validate the model and to select the most suitable coil. While attempting to minimize the weight at transmitter’s side, on the receiver side it is intended to efficiently acquire and manage the power obtained from the transmitter. In order to prove its feasibility, a temperature sensor node is used as demonstrator. The experiment results show successfully energy transportation by MAV, and wireless power transfer for the resonant configuration, being able to completely charge the node battery and to power the temperature sensor.Peer ReviewedPostprint (published version

On the common mode response of fully differential circuits

Differential circuits are often described by their differential gain and common mode rejection ratio (CMRR). This approach, however, neglects the effect that the common mode signal has on the transient response and stability of the circuit. This work shows that the actual behavior of differential circuits in front of common mode voltages is completely described by the common-to-differential mode gain and the common-mode gain. The CMRR is useful to assess common mode errors in the frequency domain, but some circuits that achieve a large CMRR have long transients or are unstablePeer Reviewe

On bio-activity related signals from contactless electrode measurements

Postprint (author's final draft

Transmural versus non-transmural in situ electrical impedance spectrum for healthy, ischemic, and healed myocardium

Electrical properties of myocardial tissue are anisotropic due to the complex structure of the myocardial fiber orientation and the distribution of gap junctions. For this reason, measured myocardial impedance may differ depending on the current distribution and direction with respect to myocardial fiber orientation and, consequently, according to the measurement method. The objective of this study is to compare the specific impedance spectra of the myocardium measured using two different methods. One method consisted of transmural measurements using an intracavitary catheter and the other method consisted of nontransmural measurements using a four-needle probe inserted into the epicardium. Using both methods, we provide the in situ specific impedance spectrum (magnitude and phase angle) of normal, ischemic, and infarcted pig myocardium tissue from 1 kHz to 1 MHz. Magnitude spectra showed no significant differences between the measurement techniques. However, the phase angle spectra showed significant differences for normal and ischemic tissues according to the measurement technique. The main difference is encountered after 60 min of acute ischemia in the phase angle spectrum. Healed myocardial tissue showed a small and flat phase angle spectrum in both methods due to the low content of cells in the transmural infarct scar. In conclusion, both transmural and nontransmural measurements of phase angle spectrum allow the differentiation among normal, ischemic, and infarcted tissue.Peer Reviewe

Applied Instrumentation : student works

Conté els treballs dels estudiants de l'assignatura: T1. Sensors and Electronic Instrumentation in the Present and Future of Gravitational Wave Astronomy. D. Canyameres, M. Font, J. Ruiz, D. Zafra. T2. Electrical signals and their physiological significance in plants. D.Gil, O. Rovira, A. Samaniego, F. Serra, J. Vilaró. T3. Eye tracking technology and its applications. A. Acitores, J. Brieva, A. Doñate, F. Poca. T4. Non invasive ultrasound in humans. M. López, M. Massó, G. Morales, J. Navas, H. Sama. T5. Ús d’un activímetre per mesures de radiació. M. Llano, M. López, M. Montaña, L. Pedro-Botet, R. Prats. T6. Utilització d’un equip d’adquisició d’imatges: qualitat d’imatge d’un tomògraf PET A.Lopera, O. Parera, J. Pérez, A. Ramos, M. Tomàs, P. Villén. T7. Usage of a Tomographic Gammacamera for Image Acquisition. J. Amigó, D. Garcín, M. Isern, M. Maroto, S. Moll. T8. Instrumentació en Radiodiagnòstic. Utilització d’un equip d’adquisició d’imatges: Tomògraf TC. Qualitat dels paràmetres del feix de radiació G. Comas, S. Vives, L. García, A. Cortés, M. Burjalès. T9. Oncologia Radioteràpica. M. Escolà, J. González, M. Jiménez, P. Montero, A. Valenzuela.2022/202