RESUMO Na agricultura irrigada, é comum a aplicação de água no solo cultivado sem critério, resultando em uso ineficiente ou não otimizado da água. Em muitos casos, a relação solo-água-planta, bem como as potencialidades e limitações dos sistemas de irrigação são ignoradas. A agricultura irrigada sustentável requer o desenvolvimento de um sistema de monitoramento da umidade do solo que evite a perda de água e melhore a eficiência do uso. O objetivo deste estudo foi desenvolver e avaliar a eficiência de um sistema inteligente de monitoramento da umidade do solo. O sistema é composto por duas estações: a primeira coleta os dados sobre parâmetros de umidade aparente do solo usando sensores, enquanto a segunda transmite esses dados para uma estação de processamento central. O sistema determina precisamente os valores atuais de umidade do solo, permitindo estimar o volume de água de irrigação necessário para atender à demanda hídrica da cultura com base na capacidade de campo. Os resultados da curva de calibração dos sensores indicam que o sistema pode medir com precisão a umidade do solo atual, auxiliando no manejo da irrigação. Para áreas irrigadas em condições de solo não saturado, recomenda-se o uso de tensiômetros devido à sua maior confiabilidade entre a capacidade de campo e o ponto de murcha permanente, garantindo práticas de irrigação mais precisas. critério casos soloáguaplanta, soloáguaplanta planta, planta solo-água-planta ignoradas estações central atual saturado recomendase recomenda se permanente precisas

ABSTRACT Water application to cultivated soil is often done without careful consideration in irrigated agriculture, leading to inefficient or suboptimal water usage. In many instances, the intricate relationship between soil, water, and plants, as well as the potential and limitations of irrigation systems, is overlooked. Sustainable irrigated agriculture necessitates the development of a soil moisture monitoring system that curtails water loss and enhances overall efficiency. This study aimed to develop and assess the efficiency of an intelligent system for monitoring soil moisture. The system comprises two stations: the first collects data on apparent soil moisture parameters using sensors, while the second transmits this data to a central processing station. The system precisely determines current soil moisture values, enabling estimation of the required irrigation water volume to meet the crop’s water demand based on field capacity. Results from the calibration curve of the sensors indicate that the system can measure current soil moisture precisely, aiding in irrigation management. For irrigated areas under unsaturated soil conditions, it is recommended to use tensiometers due to their higher reliability between field capacity and permanent wilting point, ensuring more accurate irrigation practices. usage instances plants systems overlooked stations station values crops crop s management conditions point practices

Livestock farms in Kenya face pressure to increase productivity amid rising global population. Cattle farming dominates, but small to medium-sized farms struggle with cattle insemination. Currently, visual observation is used for heat detection, with farmers maintaining farm journals. Modern methods utilizing sensors to improve estrus prediction are time-consuming, costly and need constant internet connection. This research proposes a novel approach-the use of an on-controller machine learning algorithm- for estrus prediction in cattle. Motion and temperature data was collected from two zero-grazed multiparous Holstein Friesian cows in Kiambu County, Kenya for 11 months. The data was cleaned and stored. Movement intensity profiles were derived by root-mean-squaring directional accelerometer values and averaging this over time. Validation was performed by observing cow behavior for indicators such as restlessness, mounting, and vulva swelling, with farmer predictions documented in their records. The collected data was then used to train a machine learning algorithm, with several models tested, and a neural network emerged as the best fit. The TensorFlow library facilitated the implementation of the algorithm on a microcontroller, allowing for the development of an animal tag featuring the ML algorithm. Results demonstrated 83.9% sensitivity, 89.0% specificity and 89.5% accuracy in detecting estrus, compared to farmer's visual observation, which had only 37% sensitivity. These findings underscore the potential to integrate machine learning into Precision Livestock Farming for estrus prediction, with prediction occurring directly on the animal tag offline. This integration holds promise for farmers, notably heightened insemination success rates, without necessitating significant financial investment.

ABSTRACT Industry 4.0 has revolutionised the way industries around the world operate, enabling greater efficiency and process optimisation. However, for many in developing countries, such as Cuba, the cost of implementing advanced technologies can be a significant challenge. In this context, the Velkys controller, developed by the company AlaSoluciones, is presented as a low-cost solution to boost the development of Industry 4.0 in the country. The aim of this article is to demonstrate the capabilities of the Velkys controller, presenting the hardware and software development of the device. The main element used is the ESP32 microcontroller, which provides wireless connection via Wifi and Bluetooth, as well as powerful processing capabilities. The controller firmware is based on the real-time operating system (FreeRTOS), ensuring efficient and reliable operation. This solution simplifies the transition to Industry 4.0 in contexts where the level of risk associated with the process is not extreme, such as in light manufacturing and agribusiness, among others, representing a viable and economical alternative to promote automation in Cuban industry.

RESUMEN La Industria 4.0 ha revolucionado la forma en que operan las industrias en todo el mundo, permitiendo una mayor eficiencia y optimización de los procesos. Sin embargo, para muchos países en desarrollo, como Cuba, el costo de implementar tecnologías avanzadas puede ser un desafío significativo. En este contexto, el controlador Velkys, desarrollado por la empresa AlaSoluciones, se presenta como una solución de bajo costo para impulsar el desarrollo de la Industria 4.0 en el país. El objetivo de este artículo es demostrar las capacidades del controlador Velkys, presentando el desarrollo hardware y software del dispositivo. Se utiliza como elemento principal el microcontrolador ESP32, el cual provee de conexión inalámbrica mediante Wifi y Bluetooth, así como una potente capacidad de procesamiento. El firmware del controlador se basa en el sistema operativo en tiempo real (FreeRTOS), asegurando una operación eficiente y confiable. Esta solución simplifica la transición hacia la Industria 4.0 en contextos donde el nivel de riesgo asociado con el proceso no sea extremo, como en la manufactura liviana y la agroindustria, entre otros, representando una alternativa viable y económica para promover la automatización en la industria cubana.

Abstract ‘Ataulfo’ mango is highly produced in Mexico, being harvested when it reaches its physiological maturity. This process takes at least another month for the fruit to reach consumption maturity. Warehouses and markets present important losses as the ready-to-eat status is unknown. Maturity status is determined by measuring slow and destructive physicochemical variables. An optical device based on the AS7262 spectral sensor was connected to the ESP32 microcontroller and measurements were correlated with soluble solids content (SSC), dry matter (DM) and firmness of mangoes obtained from the local market. Data analysis was carried out by partial least squares (PLS) regression, classification, regression tree (CART) and random forest (RF) models. With PLS, SST and firmness were predicted with R2 of 0.61 and 0.76, respectively. The root mean squared error of prediction (RMSEP) was 0.91 for SSC and 0.67 for firmness. With the CART model, classification accuracy was 90% for SSC and 87% for firmness of intact mango fruits. ‘Ataulfo Ataulfo Mexico maturity readytoeat ready eat unknown variables AS AS726 ESP ESP3 SSC, , (SSC) DM (DM market PLS (PLS (CART RF (RF models R 061 0 61 0.6 076 76 0.76 respectively RMSEP (RMSEP 091 91 0.9 067 67 model 90 87 fruits AS72 (SSC 06 6 0. 07 7 0.7 09 9 8 AS7

Resumo A manga cultivar ‘Ataulfo’ é altamente produzida no México e é colhida quando atinge maturidade fisiológica. Este processo leva pelo menos mais um mês para o fruto atingir maturidade de consumo. Armazéns e mercados apresentam perdas importantes porque o status “pronta para consumo” é desconhecido. O status de maturidade é determinado pela medição de variáveis físico-químicas lentas e destrutivas. Um dispositivo óptico baseado no sensor espectral AS7262 foi conectado ao microcontrolador ESP32, e suas medidas foram correlacionadas com o teor de sólidos solúveis (TSS), matéria seca (MS) e firmeza de mangas obtidas no mercado local. Análise dos dados foi realizada por meio de modelos de regressão por mínimos quadrados parciais (PLS), árvore de classificação e regressão (CART) efloresta aleatória (RF). Com o modelo PLS, TSS e firmeza, foram previstos R2 de 0,61 e 0,76, respectivamente. A raiz do erro quadrático médio de predição (RMSEP) foi de 0,91 para TSS e 0,67para firmeza. Com o modelo CART, a precisão da classificação foi de 90% para TSS e 87% para firmeza de frutos intactos. ‘Ataulfo Ataulfo fisiológica consumo pronta desconhecido físicoquímicas físico químicas destrutivas AS AS726 ESP32 ESP TSS, , (TSS) MS (MS local PLS (PLS) CART (CART RF. RF . (RF) R 061 0 61 0,6 076 76 0,76 respectivamente RMSEP (RMSEP 091 91 0,9 067para 67para 90 87 intactos AS72 ESP3 (TSS (PLS (RF 06 6 0, 07 7 0,7 09 9 8 AS7

Abstract The polymer transition temperature is a crucial parameter in the industry for knowing raw materials before starting the manufacturing process. The current work reports a novel low-cost prototype instrument to measure the transition temperature with reliable accuracy. The equipment was built using commercial load cells composed of strain gauges in combination with an Arduino® microcontroller. The prototype measurement quality was validated by measuring the transition temperatures of most commercial polymers. The obtained values were compared with values obtained by conventional thermal analysis known as differential scanning calorimetric and thermo-mechanical analysis (DSC and TMA), which results in identical values. process lowcost low cost accuracy Arduino microcontroller polymers thermomechanical thermo mechanical DSC TMA, TMA , TMA)

ABSTRACT In hydrological modeling and for the development of projects related to soil and water conservation and civil engineering, determination of water infiltration variables into the soil plays a key role. However, measuring infiltration with manual infiltrometers is work-intensive and requires several people, which casts doubts on the consistency of the process description. Our objective was to develop automated and compact systems for data acquisition by double-concentric-ring and Cornell infiltrometers. The systems are based on air differential pressure sensors and microcontrollers using open-source software and a simple construction. We developed ten sets of automatic infiltrometers for each method that were properly calibrated. The equipment was validated in the field, and the alignment of the automatically measured with the hand-measured infiltration data was considered satisfactory. The proposed systems make data records of infiltration and associated variables possible, with less operator dependence than manual measurement strategies. In addition, the enhanced resolution resulting from infiltrometer automation makes the infiltration curve more representative, especially in the initial infiltration stage. engineering role However workintensive work intensive people description doubleconcentricring double concentric ring opensource open source construction calibrated field handmeasured hand satisfactory possible strategies addition representative stage

Abstract. - Tetraplegia is a disease that can be caused by different factors, whether congenital or accidental, limiting people to live without being able to move both the lower and upper extremities. The present work shows the development of a prototype of a wheelchair for quadriplegics controlled by facial movements, this in order to give the patient independence and improve their emotional state by not requiring help to carry out the task of moving the chair. For the implementation of the prototype, an electronic circuit for analog acquisition, amplification and filtering of electromyography (EMG) signals was designed and built, which provides a signal corresponding to the degree of movement of the facial muscles. Subsequently, the signal obtained from the analog base board is digitized and processed with the help of an ATmega328p microcontroller, where additional filtering is performed and the movement made from the signals obtained is determined. This information is sent via Bluetooth connection to a second ATmega328p microcontroller in the physical prototype of the wheelchair. With the information of the action on the wheelchair's microcontroller, the conditioning of the signal is carried out to control the motors that will carry out the corresponding movement. Finally, a mobile application was designed and implemented to control the prototype through buttons, with the idea that a person responsible for the user of the chair can take control if necessary. As a result, the system was implemented on a basic commercial wheelchair, where the motors and a transmission by bands were adapted to generate the movement, this allowed basic control through facial movement and through the mobile application, however, the EMG system requires to be calibrated for different users. As future work, it is proposed to modify the transmission of the prototype and allow an automatic calibration to be applied regardless of the user.

Resumen. - La tetraplejia es una enfermedad que puede ser ocasionada por distintos factores ya sean congénitos o accidentes, limitando a las personas a vivir sin poder realizar movimientos en las extremidades tanto inferiores como superiores. El presente trabajo muestra el desarrollo de un prototipo de una silla de ruedas para tetrapléjicos controlada mediante movimientos faciales, esto con la finalidad de dar independencia al paciente y mejorar su estado emocional, al no requerir ayuda para realizar la tarea de mover la silla. Para la implementación del prototipo se diseñó y construyó un circuito electrónico de adquisición, amplificación y filtrado analógico de las señales de electromiografía (EMG), el cual otorga una señal correspondiente al grado de movimiento de los músculos faciales. Posteriormente, la señal obtenida de la placa analógica base es digitalizada y procesada con la ayuda de un microcontrolador ATmega328p, donde se realiza un filtrado adicional y se determina el movimiento realizado a partir de las señales obtenidas, esta información es enviada mediante conexión Bluetooth a un segundo microcontrolador ATmega328p en el prototipo físico de la silla de ruedas. Con la información de la acción sobre en microcontrolador de la silla de ruedas, se realiza el acondicionamiento de la señal para el control de los motores que realizarán el movimiento correspondiente. Por último, se diseñó e implementó una aplicación móvil para el control del prototipo mediante botones, con la idea de que un responsable del usuario de la silla pueda tomar el control en caso de ser necesario. Como resultados se implementó el sistema sobre una silla de ruedas comercial básica, donde se adaptaron los motores y una transmisión por bandas para generar el movimiento. Esto permitió el control básico a través del movimiento facial y por medio de la aplicación móvil, sin embargo, el sistema de EMG requiere ser calibrado para usuarios diferentes. Como trabajo futuro se plantea modificar la transmisión del prototipo y permitir una calibración automática para ser aplicado indistintamente del usuario.

ABSTRACT Soil erosion studies using rainfall simulators are generally expensive and time consuming. Thus, the aim of this study was to develop a prototype of an automatic runoff collector, capable of real-time quantifying runoff volume and soil loss in field trials using a rainfall simulator. The used sensors were chosen based on the type A uncertainty computed from different volumes of water and concentrations of sediment. Through specific programming, the runoff volume, sediment concentrations and the time of occurrence of the collections corresponding to each 200 cm³ of runoff were recorded on a micro-SD card. The robustness of the calibration and the programming developed were also evaluated in the Arduino Mega® 2560 microcontroller. The pressure (PSI.420) and turbidity (ST100) sensors were selected for developing the prototype, which was evaluated in the field with the InfiAsper rainfall simulator. Then, the data collected automatically by the sensors were compared to those obtained by manual measurement. The automatic runoff collector equipped with the PSI.420 and ST100 sensors has potential to obtain and store runoff data, and it was effective in evaluating the erosion process, generating mean errors of 12.25 and 13.16% for runoff volume and soil loss, respectively. The proposed prototype has a low cost of manufacture, in addition to optimizing the collection of erosion data in studies with rainfall simulators. consuming Thus realtime real simulator 20 cm microSD micro SD card Mega 256 microcontroller PSI420 PSI 420 (PSI.420 ST (ST100 Then measurement PSI.42 ST10 process 1225 12 25 12.2 1316 13 16 13.16 respectively manufacture 2 PSI42 42 (PSI.42 (ST10 PSI.4 ST1 122 1 12. 131 13.1 PSI4 4 (PSI.4 (ST1 PSI. 13. (PSI. (ST (PSI

RESUMO Estudos relacionados à erosão do solo usando simuladores de chuva são geralmente onerosos e demorados. Assim, o objetivo deste estudo foi desenvolver um protótipo de coletor automático de escoamento superficial, capaz de quantificar em tempo real o volume de escoamento superficial e a perda de solo em ensaios de campo utilizando um simulador de chuva. Os sensores utilizados foram escolhidos com base na incerteza tipo A calculada a partir de diferentes volumes de água e concentrações de sedimentos. Por meio de programação específica, o volume da enxurrada, as concentrações de sedimentos e o tempo de ocorrência das coletas correspondentes a cada 200 cm³ de enxurrada foram registrados em um cartão micro-SD. A robustez da calibração e a programação desenvolvida também foram avaliadas no microcontrolador Arduino Mega® 2560. Os sensores de pressão (PSI.420) e de turbidez (ST100) foram selecionados para o desenvolvimento do protótipo, o qual foi avaliado em campo com o simulador de chuva InfiAsper. Em seguida, os dados coletados automaticamente pelos sensores foram comparados com os obtidos por medição manual. O coletor automático equipado com os sensores PSI.420 e ST100 tem potencial para obter e armazenar dados de escoamento, e foi eficiente na avaliação do processo erosivo, gerando erros médios de 12,25 e 13,16% para volume de escoamento e perda de solo, respectivamente. O protótipo proposto possui baixo custo de fabricação, além de otimizar a obtenção de dados de erosão em estudos com simuladores de chuva. demorados Assim específica 20 cm microSD. microSD micro SD. SD micro-SD Mega 2560 PSI420 PSI 420 (PSI.420 ST (ST100 InfiAsper seguida manual PSI.42 ST10 erosivo 1225 12 25 12,2 1316 13 16 13,16 respectivamente fabricação 2 256 PSI42 42 (PSI.42 (ST10 PSI.4 ST1 122 1 12, 131 13,1 PSI4 4 (PSI.4 (ST1 PSI. 13, (PSI. (ST (PSI

ABSTRACT Monitoring the movements of ruminant animals is one of the most challenging tasks. In animals that act according to their habits, it is difficult to label such movements and transfer them to farmers. Monitoring and recording the movement and behavior of animals on a farm is an adopted method for successfully determining the duration of the estrus cycle in ruminant animals. The Internet is a technology that offers remarkable solutions for such applications. The aim of this study is to determine the hourly step counts and to find the estrus period in the most accurate way with a circuit design applied to the ankles of animals using an IoT-supported microcontroller. The data is transferred to the web environment wirelessly and monitored via wi-fi communication signals. This wireless wearable and network equipment determines the step count and monitors the animal's abnormal body temperature. An IoT-supported microcontroller provides wireless communication, high-speed data transmission, and low power consumption. Insemination was ensured by testing different animals on the application farm. The data is monitored in real-time, and the system gives an alert. Low cost, high reliability, and being able to be watched over the internet are the advantages of the system. This study helped develop new techniques and provided a low-cost proposition for testing wearable technologies on animals. tasks habits farmers applications IoTsupported IoT supported wifi wi fi signals animal s temperature highspeed speed transmission consumption realtime, realtime real time, time real-time alert cost reliability lowcost

RESUMO A monitorização dos movimentos dos animais ruminantes é uma das tarefas mais difíceis. Em animais que agem de acordo com os seus hábitos, é difícil rotular esses movimentos e transferi-los para os agricultores. A monitorização e o registo dos movimentos e do comportamento dos animais numa exploração é um método adoptado para determinar com êxito a duração do ciclo de cio em animais ruminantes. A Internet é uma tecnologia que oferece soluções notáveis para tais aplicações. O objectivo deste estudo é determinar as contagens horárias de passos e encontrar o período de cio da forma mais precisa possível com um design de circuito aplicado aos tornozelos dos animais utilizando um microcontrolador suportado pela IoT. Os dados são transferidos para o ambiente Web sem fios e monitorizados através de sinais de comunicação wi-fi. Este equipamento vestível e de rede sem fios determina a contagem de passos e monitoriza a temperatura corporal anormal do animal. Um microcontrolador suportado pela IoT fornece comunicação sem fios, transmissão de dados a alta velocidade e baixo consumo de energia. A inseminação foi assegurada através de testes com diferentes animais na quinta de aplicação. Os dados são monitorizados em tempo real e o sistema emite um alerta. O baixo custo, a elevada fiabilidade e a possibilidade de ser observado através da Internet são as vantagens do sistema. Este estudo ajudou a desenvolver novas técnicas e forneceu uma proposta de baixo custo para testar tecnologias vestíveis em animais. difíceis hábitos transferilos transferi los agricultores aplicações wifi. wifi wi fi. fi wi-fi animal energia aplicação alerta

This work presents the development of a low-cost spin coater for thin film deposition as an alternative to commercial equipment that have high acquisition cost. The proposed spin coater uses a brushless motor taken from an unused hard disk, which is activated through the association of an electronic speed controller (ESC) and an Arduino microcontroller. During deposition, the rotating substrate is attached with a vacuum clamping system. For the control, the system uses a Hall effect sensor to read the engine speed. The rotation readings performed by the equipment sensor were validated with a tachometer. Finally, TiO2 films were deposited on glass substrates with ITO (Indium Tin Oxide) and characterized by UV-Vis spectroscopy to obtain the transmittance of the films at different rotation speeds. lowcost low cost disk ESC (ESC microcontroller control tachometer Finally TiO Indium Oxide UVVis UV Vis speeds

The present study proposes a simple and inexpensive photometric method for the selective determination of Ag(I). This method employed a home-made double beam photometer for the determination of silver ions based on an optode sensor prepared by immobilization of 5-(P-Dimethylaminobenzylidene)-rhodanine (PDR) on triacetyl cellulose (TAC) membrane. Two green LEDs as sources of light and light-dependent resistors (LDRs) as detectors were used in the proposed device. The LEDs are turned on by a programmable microcontroller that receives signals from light passed through the sensor, and the absorbance is calculated and displayed on a Liquid-crystal display (LCD) screen. With the optimum conditions, the calibration plot was linear in the concentration range of 0.5-6 μg mL-1. For five replicate determinations of 2 μg mL-1 Ag(I) and the related detection limits, the relative standard deviations were 2.29% and 0.25 μg mL-1, respectively. The method was applied successfully for determining silver in a silver sulphadiazine cream, a radiology effluent, and radiology film samples and the results obtained were in good agreement with those of the standard flame atomic absorption spectroscopy (FAAS) method.

Abstract This paper presents an improved real time single-target target tracking system based on Cam-Shift and advanced Kalman filter algorithms. The paper proposes a simple low implementation cost scheme while keeping the high tracking performance. Two degrees of freedom target tracking system based on two hybrid stepper motors with their drive systems is fully designed and implemented to improve the tracking accuracy while keeping low-cost. The potential of the proposed algorithm lies in its ability to accurately detect, track, and produce firing commands on the designated target while utilizing low cost on the shelf embedded Microcontroller boards. A low-cost Universal Serial Bus port (USB) camera is used and integrated with the proposed algorithm to detect and track maneuvering targets. A series of experiments for stationery and moving objects are conducted to evaluate the proposed system efficiency. The proposed system enables accurate performance for tracking static and moving objects. Hence it provides a simple and low implementation cost scheme for real time object tracking applications.

Resumen El Internet de las Cosas es una tecnología de gran aplicación por su versatilidad en áreas como la agronomía, las aplicaciones sanitarias y la industria. Además, la portabilidad hace que estos dispositivos sean asequibles. Las placas de desarrollo de IoT se comunican a través de mensajes transmitidos por Wi-Fi a través de Internet, según el funcionamiento interno de la placa de desarrollo de IoT, el consumo de energía puede variar en dicha transmisión. Además, este consumo podría cambiar si la placa se alimenta con diferentes fuentes de alimentación y la cantidad de mensajes transmitidos por Wi-Fi. Este documento proporciona una metodología para adquirir un perfil de energía al enviar datos (byte) mediante el protocolo de transporte de telemetría de cola de mensajes (MQTT) en la placa de desarrollo DEVKIT V1 NodeMCU-32 (ESP32). Se utilizaron tres fuentes de alimentación diferentes para la placa, una batería LiPo 3.7, un banco de energía USB de 5v y una batería recargable NiMh de 9V. El mayor consumo de corriente obtenido fue al utilizar una batería de 3.7, seguido de 5v y el menor consumo de corriente fue al utilizar 9v. Sin embargo, los resultados demuestran que cuando se usa la fuente de alimentación de 9v, el consumo de energía es dos veces mayor que cuando se usa la fuente de alimentación de 3,7v. Por lo tanto, la mejor fuente de voltaje para transmisión y consumo de energía utilizando una placa de desarrollo NodeMCU-32 será de 3,7 voltios.

Abstract Internet of Things is a highly applicable technology due to its versatility in areas such as agronomy, health applications, and industry. Besides, portability makes these devices affordable. IoT development boards communicate through Wi-Fi transmitted messages via the Internet, depending on the inner workings of the IoT development board, energy consumption can vary in such transmission. Furthermore, this consumption could change if the board is powered by different power supplies and the quantity of Wi-Fi transmitted messages. This paper provides a methodology to acquire an energy profile when sending data (byte) using Message Queue Telemetry Transport (MQTT) protocol on DEVKIT V1 NodeMCU-32 (ESP32) development board. Three different power supplies were used for the board, a 3.7 LiPo Battery, 5v usb Power bank and 9V NiMh rechargeable battery. The higher current consumption obtained was using a 3.7 battery, followed by 5v and the lowest current consumption was when using 9v. However, results demonstrate that when using the 9v power supply the energy consumption is two times higher than using 3.7v. Therefore, the best voltage source for transmission and energy consumption using a NodeMCU-32 development board will be 3.7 volts.

RESUMEN En este trabajo se diseñó e implemento un Analizador de Energía Eléctrica Trifásico basado en la aplicación de la Red Adaline para descomponer las tensiones e intensidades de cada fase en sus armónicos. Para sensar las tensiones se usaron transformadores de pequeña potencia y circuitos con amplificadores Operacionales. Para el sensado de las intensidades se usaron bobinas Rogowski, más una etapa subsiguiente con circuito acondicionador de la señal el cual realiza la doble función de amplificación-integración, y que necesita de un ajuste cuidadoso de los componentes para no distorsionar las señales sensadas. Las señales son procesadas por un microcontrolador de bajo costo AtMega 328P optimizando los recursos en la programación de la red Adaline. Las fórmulas para la medida de las magnitudes trifásicas y por fase se basaron en el Estándar IEEE 1459. Finalmente se probó el desempeño del analizador propuesto en una medida realizada en un tablero industrial de tres conductores accesibles, y se contrastaron sus valores con las de una pinza amperimétrica Fluke 375. Los resultados muestran el correcto funcionamiento del analizador y la buena precisión y exactitud de las medidas de valores eficaces de tensiones, intensidades y sus armónicos.

ABSTRACT In this work, a Three-Phase Electric Energy Analyzer was designed and implemented based on the application of the Adaline Network to decompose the phase voltages and currents into their harmonics. For the sensing of the voltages, small power transformers and circuits with Operational Amplifiers were used. For the sensing of the currents, Rogowski coils were used, in addition to a subsequent stage with a signal conditioning circuit that performs the double function of amplification-integration and that requires a careful adjustment of the components so as not to distort the sensed signal. The signals are processed by a low-cost AtMega 328P microcontroller optimizing the resources in the programming of the Adaline network. The formulas for measuring three-phase and per-phase magnitudes were based on the IEEE 1459 Standard. Finally, the performance of the proposed analyzer was tested in a measure performed on an industrial panel of three accessible conductors, and its values were compared with those of a Fluke 375 clamp meter. The results show the correct operation of the analyzer and the precision and accuracy of the measurements of rms values of voltages and currents and their harmonics.

Resumen Debido al creciente desarrollo tecnológico de los sistemas embebidos y el internet de las cosas (IoT), los dispositivos basados en microcontroladores se aplican cada vez más en diversas áreas del conocimiento. En este contexto, las plataformas y productos educativos online se consideran laboratorios virtuales remotos, ya que los estudiantes pueden acceder a los dispositivos físicos en cualquier lugar siempre que dispongan de un sistema informático conectado a internet. En este sentido, este trabajo describe el diseño y desarrollo de una plataforma con cuatro productos educativos en línea para la enseñanza de microcontroladores e IoT. Estos productos educativos están basados en software de código abierto, lo que permite su distribución gratuita en línea y el acceso a ellos desde un servidor en la nube. El enfoque de código abierto y multiplataforma (Linux, Windows® y Mac OSX) permite una mayor interacción y accesibilidad del usuario. Los productos educativos en línea hacen posible la programación del firmware del microcontrolador ESP32 de forma remota a través de OTA (Over the Air) y de sistemas embebidos Linux basados en Raspberry Pi (Rpi), permitiendo aplicaciones virtuales de laboratorio de microcontroladores. Además, los productos educativos en línea permiten manipular los pines vía internet a través de la interfaz gráfica de los microcontroladores ESP32 y ESP8266, así como del Rpi. Como resultado, se probó la plataforma en línea propuesta, ejecutándola en un servidor en la nube, y se validaron los cuatro productos educativos de aprendizaje a distancia y la aplicación real de microcontroladores e IoT, que se encuentran operativos, tal como fueron diseñados.

Abstract Due to the increasing technological development in embedded systems and the Internet of Things (IoT), devices based on microcontrollers are being increasingly applied in various areas of knowledge. In this context, online educational platforms and products are considered virtual remote laboratories, because students can access the physical devices anywhere as long as they have a computer system connected to the internet. In this sense, this work describes the design and development of a platform with four online educational products for teaching microcontrollers and IoT. These educational products are based on open-source software, which enables their free online distribution and the access to them from a cloud server. The open-source and multiplatform (Linux, Windows®, and Mac OSX) approach enables a greater user interaction and accessibility. The online educational products make possible the remote programming of the ESP32 microcontroller firmware via OTA (over the air) and Linux embedded systems based on Raspberry Pi (Rpi), enabling virtual microcontroller laboratory applications. In addition, the online educational products enable the manipulation of GPIO pins via the Internet through the graphical interface of the ESP32 and ESP8266 microcontrollers and the Rpi. As a result, the proposed online platform was tested, running it on a cloud server, and the four-distance learning educational products and the actual microcontroller and IoT application have been validated, and are operating as designed.