Revista elektron

1-6

Authors: Federico Gabriel D'Angiolo, Julio Guillermo Zola

This work describes a procedure to model a Boost converter using State Variables. An example will be taken to describe the procedure, a converter used within a UPS that must deliver a constant voltage of 400V to power a bus. The input voltage of this converter is given by a set of batteries that can be fully or partially charged, so the input voltage can vary between two possible extreme values. An analysis of the Boost converter circuit will be carried out as an introduction to later carry out the corresponding modeling. This modeling will allow to analyze its stability, the variations in the output voltage in the face of changes in the input, as well as the different disturbances that may occur.

15-19

Authors: Guillermo R Catuogno, Guillermo O Acosta, Carlos G Catuogno

This paper presents the implementation of a data management system. The data is colleted from a wind-solar microgrid installed in a remote rural school. This system was made using free software, and consists of the acquisition of data from the wind-solar generator, the storage of the information in a relational database and the visualization of the information processed through the internet by means of a web browser. The developed system was installed in the Puerta del Sol area, located in the north of the province of San Luis and consists of a programmable logic controller (PLC) that collects the information of the process, a human-machine interface (HMI) screen for local visualization process data, and a computer that contains a web server and a database manager (located at the University facilities). An application programmed in Python runs in the computer and periodically queries the PLC via the internet about the process information and saves this information in a MariaDB database (MySQL compatible). At the same time, the web server responds through applications programmed in PHP language to the queries that, from a remote external client, are requested through an HTML page. The behavior of the proposed management system has been validated with the experimental results obtained.

32-36

Authors: María de los Angeles Gómez López, Carlos Sueldo, Leonardo Del Sancio

This paper aims at presenting a retention strategy used by the Electronic Engineer career from the Universidad Nacional de Tucumán in order to motivate, integrate and keep their students. The procedure used is the implementation of practical workshops aimed at students of all years of the career who have as premise “to learn by doing”. The workshops seek to bring the student in all aspects of the exercise of the profession. They are taught one at a time in sequence and are assessed by completing a simple project. The results of the procedure used were measured by the number of enrolled students and surveys verifying satisfaction.

45-55

Authors: Pablo Bertinat, Juan Salerno, Marcelo Castello, Rafael Oliva

This paper delineates the different stages in the design and evolution of a datalogger system and its associated software. It was developed within the framework of a Project aimed at the study and processing of wind data for power generation, and carried out with open source tools. This project has focused on the development of in-house technology, with capabilities and performance comparable to equipment available on the market. Commercial off-the-shelf systems have been analysed, as well as associated software in order to set the general features and requirements for the prototype. An important number of industry-standard features in the processing of wind data for electric power generation have been considered. Hardware was developed and a web-based system located in an in-house server have been deployed, both of which work together to fulfill the proposed functions.

64-69

Authors: Leandro José Ferrari, Sergio Daniel Leoni, Christian Luis Galasso, Martin Ezequiel Paz

This work describes the implementation and testing of a FSK demodulator, within the framework of a modem re-engineering for navy communications. It was developed over a Spartan 6 XCSLX25 FPGA with its code in VHDL. For testing, a modulator was implemented in a STM32F407 microcontroller where different noise levels were added to the signal to try out the system.

77-82

Authors: Luis Antonio Orbegoso Moreno, Cristian Rodríguez, Edgar Valverde

The present work consisted of the implementation of a method for the solution of the inverse kinematic problem of a quadruped robot in four limbs with 3 degrees of freedom each. The proposed solution was supported by the application of an iterative method (Newton-Raphson) and special emphasis was placed on fine-tuning the algorithm parameters, that is, the number of iterations and the threshold distance, in order to guarantee the convergence of the solution in a few iterations. The work proposed to use the same method both for the function of walking by following the trajectory of a closed Bézier curve of five points, as well as for the control of body posture through the development of pitch and roll movements, and yaw from the base. The results of this solution were simulated in the PyBullet module to which the numerical values of the joints of the quadruped robot obtained from the inverse kinematics were exported to validate its behavior and movements in a simulated physical environment.

40-51

Authors: Hernán Emilio Tacca

A method for high power pulse transformer design is presented based on analytical assumptions that lead to sizing equations allowing one step design which may then be improved by iteration. An example of a transformer design procedure used in a pulse generator for electroporation is included.

58-63

Authors: Martín Alejandro Heredia, Facundo Santiago Larosa, Ramiro Adrián Ghignone, Federico Alejandro Vázquez Saraullo, Hernán Pablo Mendes Gouveia

In embedded systems a wide variety of applications can be solved or approached using different technologies, such as microcontrollers, FPGA, Systems on Chip (SoC), among others. Even though the volume of information and solutions available that focus on low cost based microcontrollers is quite vast, FPGA and SoC do not have as many resources readily available despite being essential for critical applications and also those in which higher speeds for data processing are required. Not only that, but the high cost of development boards, discontinuity between contents taught in higher education and knowledge required in practical fields, and overall lack of learning resources all add difficulty to any professional looking to specialize themselves in this field of knowledge. It is for this reason that this work proposes an Open Platform for Digital Design Learning on FPGA-based Systems, which looks to facilitate the learning process for any student or professional that wants to get started in this field. For this purpose this work proposes the following: a low-cost development board alongside a set of learning tools and examples which can fit both self-taught students and lecture-based learning environments, and the creation of a national collaboration network to give support to students and teachers who want to join and participate in the project.

69-73

Authors: Roberto M. Insabella, Martín Germán González, Ligia Ciocci Brazzano, David Barbieri

In this work we present the study, development and characterization of a cylindrical focused ultrasonic sensor based on a piezoelectric polymeric material. For the design and implementation of the transducer, we carried out simulations using the commercial tool k-Wave and we used a construction method with great repeatability and low cost. For the characterization of the detection system (sensor + amplifier), we made electrical and acoustic measurements that allowed to determine its sensitivity and equivalent pressure noise. The results of this work show that the implemented sensor is suitable for optoacoustic tomography.

81-86

Authors: Tomás Medina, Lucas Leiva, Martín Vázquez

The use of image processing systems is becoming frequent and is appropriate in edge computing. However, the demands on power consumption and high performance prevent the use of standard processing platforms. Thus, FPGAs are a good option for the development of computer vision systems because they are capable of exploiting parallelism. On the other hand, the design flow of current FPGA synthesis tools supports high-level languages as input descriptions, in contrast to hardware description languages. High-level synthesis (HLS) automates the design process by transforming an algorithmic description into digital hardware meeting design limitations. However, image processing experts may find challenging the hardware integration with the rest of the system components, e.g. capture and display interfaces. This work presents a basic design for the construction of image processing applications based on Zynq and a guide for its use, which solves this problem, allowing the agile generation of embedded image processing solutions. Additionally, a methodology is provided, which facilitates the efficient development of image processing embedded solutions in an agile way.

93-99

Authors: Natalia Iglesias, Pilar Bulacio, Elizabeth Tapia

A communication architecture is presented to enable cloud services around agricultural machinery in rural areas with limited connectivity infrastructure. This architecture is made up of three modules named: on-board unit, gateway and cloud service. Which together allow extending the scope of communication coverage, enabling the exchange of data from agricultural machinery to the cloud. The architecture is developed using low-cost hardware and open-source libraries that allow its rapid implementation. The results obtained, in terms of communication latency, indicate that the solution is suitable for monitoring applications in agricultural machinery using ISOBUS.

107-113

Authors: Juan Pablo Valeo, Sebastian Gregoracci, Leticia María Seijas, Juan Alberto Etcheverry

There is a technological gap between Argentina and other countries. This work presents the Automated LPR Parking System for Argentinian Plates SAE (in Spanish, Sistema Automatizado de Estacionamiento) designed and developed in its prototype version for a private company, to control and manage the entry, stay and exit of vehicles in parking lots. The system is composed by two main modules: the automatic license plate recognition system and the Principal System Board. This board allows the connection of the central unit with peripherals such as magnetic field sensors, access barriers and infrared barriers. In addition, the system manages a database that stores the necessary information for the parking management. Registered users that pay monthly and ocasinal users are considered. Furthermore, the system implements a mechanism for vehicle size detection to determine the value of the parking fees. SAE handles both hardware and system failures and exceptional situations. In addition, the entry and exit of vehicles are handled simultaneously.

1-7

Authors: Juan Carlos Agotegaray, Andrea Pinzón, Emanuel Lera

This paper presents the development of an automated electric generators test bench for low power wind energy in urban applications. The bench allows testing electric generator under similar operating conditions to real, electric generator coupled to a wind turbine in urban environments, which allows to determine specific parameters: electric current, voltage, power.

14-20

Authors: Rosa Marina Corti, Javier Belmonte, Néstor Marcón, Marcelo Pistarelli, Roberto Martínez, Juan Pablo Vecchio

Traditional wireless sensor networks work with scalar data like temperature o humidity because they have strong restrictions on bandwidth and energy consumption. Nevertheless, in recent years, technological advances have permitted a significant growth in the use of these networks for processing and transmitting complex signals like audio, video or vibrations. This work reports the development of an adaptable platform for sensor nodes, which are able to measure, process, store and wirelessly transmit diverse physical variables. The design of these nodes allows the adaptation of them for the use in applications that require to measure and process signals of varied complexity. In addition, the nodes permit the wireless transmission of the information obtained from the local processing of the signals mentioned above. Finally, the adaptation of the platform to measure vibration in road bridges is described as a case study.

27-34

Authors: Federico Luna, Silvina Boggi, Walter Gustavo Fano

Metamaterials in microwave frequency bands have been widely explored in the development and design of antenna structures and arrays. In this paper, the so-called Yang cell have been studied. When these cells are periodically arranged on a plane, the resulting metamaterial structure shows lower band-gap frequencies than structures composed of other unit cells of the same size. The electric and magnetic fields in the first two modes of electromagnetic propagation in the unit cell have been studied. Four equivalent circuit models of the unit cell have been developed in order to easily and quickly obtain the frequency response of the metamaterial structure. These models are explained in this paper, and were validated using full-wave computational electromagnetic methods.

58-66

Authors: Axel Montes de Oca, Santiago Verne, Nilda Vechiatti, Carlos Muravchik

Este trabajo trata sobre el diseño y construcción de un altoparlante direccional, también conocido como parlante de matriz paramétrica (PAL). El funcionamiento del mismo se basa en los principios de un fenómeno denominado autodemodulación que sucede cuando haces de alta frecuencia interactúan en un medio viscoso, debido a las propiedades no lineales del mismo. El sonido obtenido luego de la autodemodulación se forma en el haz de la señal portadora ultrasónica propagándose más allá de la distancia en la que la portadora ha sido suficientemente atenuada. Esto genera una señal audible focalizada y por ende un patrón polar direccional de ángulo angosto. En el presente trabajo se evalúan dos métodos de modulación: en amplitud con doble banda lateral (AM-DBL) y por variación de ancho de pulso (PWM). Se analiza experimentalmente su efecto en la direccionalidad, nivel de presión sonora y distorsión armónica.

75-83

Authors: Nilda Vechiatti, Federico Iasi, Nicolás Tati, Alejandro Armas, Daniel Tomeo, Luis Cosentino

Este trabajo trata del desarrollo de un sistema destinado al registro de sonido holofónico y a la obtención de parámetros acústicos biaurales que caracterizan la percepción espacial del sonido. En la primera parte se presenta la implementación de un prototipo de maniquí acústico de bajo costo, simulador de cabeza y torso (HATS), al que se le analizaron sus características antropométricas y sus respuestas en frecuencia. En la segunda parte se describen los algoritmos desarrollados para procesar los datos medidos a través del HATS. Finalmente se muestras algunos resultados calculados con el sistema desarrollado y se los compara con los obtenidos mediante un software comercial. Las aplicaciones del sistema de medición desarrollado son varias, entre ellas pueden mencionarse: el registro de sonidos 3D, el cálculo de parámetros subjetivos en acústica de salas, o la medición de dosis de ruido para evaluar el daño auditivo de las personas expuestas a ruido a través de auriculares.

91-102

Authors: Marcos Eduardo Bierzychudek, Héctor Laiz

Constantemente utilizamos los resultados de medidas para comercializar, tomar decisiones, compatibilizar elementos o valorar riesgos. El Sistema Internacional de Unidades (SI) es imprescindible para expresar los resultados de manera clara y comparable. El SI es el resultado de una convención diplomática cuyo objetivo es lograr la compatibilidad internacional de las mediciones para el comercio, la ciencia y el desarrollo sustentable. Recientemente, se aprobó una nueva definición del SI, en la cual el sistema es definido en términos de siete constantes de referencia cuyo valor numérico es establecido por convención. De esta manera, se dejó de lado la definición del kilogramo basada en un artefacto, la definición del ampere basada en un experimento teórico, y la definición del kelvin y del mol basadas en propiedades de sustancias. Ahora, cualquier unidad del sistema puede ser derivada a partir de las constantes de referencia. Esta redefinición tiene como objetivo la estabilidad a largo plazo, la consistencia y la coherencia del sistema, adecuándose a las necesidades de los usuarios y brindado un marco formal para potenciar el crecimiento de la ciencia y la tecnologı́a. En este artículo, se dará especial atención a los efectos de la redefinición en las unidades eléctricas.

112-119

Authors: Luis Horacio Arnaldi

Se realiza un análisis de los factores intervinientes en la formación de la señal de los tubos fotomultiplicadores. Estos dispositivos son detectores de luz extremadamente sensibles, muy utilizados en aplicaciones de conteo de fotones. Se aborda el estudio y diseño de la red de polarización de los tubos fotomultiplicadores, sentando las bases para pruebas de desempeño. A través del análisis detallado del funcionamiento de los tubos fotomultiplicadores y su electrónica de polarización, se espera que el usuario pueda separar la respuesta del circuito de polarización de la información que llevan los pulsos de salida.

1-5

Authors: Federico Miyara

A circuit theory approach is presented for the analysis of acoustically coupled spaces. It is based on energy flow and balance with a similar analogy to the one used for solving dynamic thermal systems, where acoustic power is analog to electric current and acoustic energy density is analog to voltage. Room volume is equivalent to capacitor and sound absorption is equivalent to a resistor. From these analogies and Laplace-transformed models it is possible to get stationary or transient response solutions.

10-15

Authors: Ariel Velis, Carlos Manuel Posse, Ana Rizzo La Malfa

Vertical gardens, called "Greenery Systems", are a new tendency in modern constructions. They are applied increasingly more frequently on those buildings where energy and ecological considerations, environmentally friendly, are a priority. Some main features of these technologies are: thermal insulation improvement, environmental pollution filtering, acoustic absorption, water retention and a friendly aesthetic appearance. Vertical gardens can have dissimilar acoustic features because they depend on the kind of support, substrate and vegetation used. For this reason, nowadays, collected data are very diverse and incomplete and it is necessary to expand the data available to provide more alternatives with practical application. In this work, acoustic absorption of modular vertical greening was studied. Each module was developed with a rigid PVC base covered with fibrous material forming pockets, where the substrate and vegetation were placed. The plant species that were used are some of the most widespread ones in the region, in order to achieve a good adaptation and simple maintenance.

24-28

Authors: Georgina Alejandra Lizaso, Nicolás Casais Dassie, Damián Andrés Fernández, Jorge Petrosino

Acoustic wave reflections from corrugated surfaces are analyzed. For this work, a proposal of Yi-Fan Zhu on a relatively simple model of metasurface is taken as a basis. Each groove of a corrugated surface can be considered analogous to a linear array, while the depth of its grooves is related to the phase of each source. Zhu's original proposal takes the phase gradient of the arrangement as a design parameter. In this paper we analyze the advantages of surface design from the time-delay gradient. It also presents the possibility of impose brief delays in the whole pattern of reflections independently of the general design process.

39-45

Authors: Sebastian Pablo Ferreyra, Gabiel Agustín Cravero, Ana Maria Moreno, José Yamil Simes, Juan Facundo López

Acoustics is an intrinsically interdisciplinary science that has changed the way it has been taught in recent decades. Currently in higher education its teaching is varied and even opposed, applying methods such as theoretical-practical lectures to problem-based learning where the student is the main protagonist of their own learning, since the inquiry conducted by the student leads the process. At the same time, the new paradigms of higher education prioritize students'research skills. This document describes two examples of guided research, applied pedagogical innovation in the subject Fundamentals of Acoustics and Electroacoustic of the National Technological University, showing favourable results in the learning process.

52-57

Authors: Pablo Etchepareborda, Francisco Veiras, Arturo Bianchetti, Alejandro Federico, Martin German Gonzalez

In this work we present an optical method for the direct determination of the piezoelectric coefficient of polymeric thin films. This is achieved through the measurement of nanometric mechanical displacements generated in the film when it is excited by low frequency harmonic electrical signals (0.5 Hz). The system is based on the temporal speckle pattern interferometry technique and the recovery of phase by using a bivariate empirical mode decomposition framework. The experimental scheme was used on a sample of vinylidene polyfluoride deposited on a glass substrate. The sample presents similar conditions to those found in the characterization of complex fluids by photoacoustic techniques. The measured value agrees with those obtained by other methods and with the value reported by the manufacturer.