Papers by samuel e. de Lucena
Despite the frequent use of stepping motors in robotics, automation, and a variety of precision i... more Despite the frequent use of stepping motors in robotics, automation, and a variety of precision instruments, they can hardly be found in rotational viscometers. This paper proposes the use of a stepping motor to drive a conventional constant-shear-rate laboratory rotational viscometer to avoid the use of velocity sensor and gearbox and, thus, simplify the instrument design. To investigate this driving technique, a commercial rotating viscometer has been adapted to be driven by a bipolar stepping motor, which is controlled via a personal computer. Special circuitry has been added to microstep the stepping motor at selectable step sizes and to condition the torque signal. Tests have been carried out using the prototype to produce flow curves for two standard Newtonian fluids (920 and 12 560 mPa • s, both at 25 • C). The flow curves have been obtained by employing several distinct microstep sizes within the shear rate range of 50-500 s −1. The results indicate the feasibility of the proposed driving technique.
Revista SODEBRAS, 2021
A SODEBRAS-Soluções Para o Desenvolvimento do País-publica artigos científicos das mais diferente... more A SODEBRAS-Soluções Para o Desenvolvimento do País-publica artigos científicos das mais diferentes áreas do conhecimento. Devido seu caráter interdisciplinar e a qualidade de seu corpo editorial a Revista tem sido utilizada por pesquisadores do Brasil e do mundo, para publicar estudos de alta relevância para o desenvolvimento técnico-científico da sociedade humana. Além disso, a SODEBRAS conta com o apoio da UNALAR, editora que está no mercado há mais de duas décadas; e também do ITANACIONAL, instituto de ensino e pesquisa localizado em Cisneiros-distrito de Palma-MG. Para contribuir com uma dinâmica ainda maior, no que diz respeito à circulação e a produção do conhecimento, a SODEBRAS adota uma periodização mensal. Sabe-se que em um mundo de rápidas mudanças e de constantes transformações a ciência precisa estar na vanguarda da propagação de informações. Além disso, as edições possuem formato eletrônico de acesso livre e gratuito, assim como indexação nacional e internacional. Abaixo, os artigos desta edição e seus respectivos autores. No mês de dezembro de 2021 a edição 192, última do ano, a SODEBRAS publica 13 artigos das mais variadas áreas do conhecimento humano.
IMTC Instrumentation and Measurement Technology Conference, 2005
A 1000-kgf resistive strain-gauge load cell has been developed for quality testing of rocket prop... more A 1000-kgf resistive strain-gauge load cell has been developed for quality testing of rocket propellant grain. A 7075-T6 aluminum alloy has been used for the elastic column, in which 8 uniaxial, 120-Q strain gauges have been bonded and connected to form a full Wheatstone bridge to detect the strain. The chosen geometry makes the transducer insensitive to moments and, also, to the temperature. Experimental tests using a universal testing machine to imposed compression force to the load cell have demonstrated that its behavior is linear, with sensitivi(V of 2.90 f.l V/kgf ±0.34%, and negligible hysteresis. The designed force transducer response to a dynamic test has been comparable to that of a commercial load cell.
– This paper presents a discussion on the potential use of high tech garbage, including electroni... more – This paper presents a discussion on the potential use of high tech garbage, including electronic waste (e-waste), as a source of mechanisms, sensors and actuators, that can be adapted to improve the reality of microprocessor systems labs, at low cost. By means of some examples, it is shown that entire subsystems withdrawn of high tech equipments can be easily integrated into existing laboratory infrastructure. As examples, first a precision positioning mechanism is presented, which was taken from a discarded commercial ink jet printer and interfaced with a microprocessor board used in the laboratory classes. Secondly, a read/write head and its positioning mechanism has been withdrawn of a retired CD/DVD drive and again interfaced with the microprocessor board. Students who have been using these new experiments strongly approve their inclusion in the lab schedules.
Abstract: This paperwork presents the complete circuitry used to build a microcontroller-based pH... more Abstract: This paperwork presents the complete circuitry used to build a microcontroller-based pH-meter. Key control software is also discussed. An industry-standard glass combination electrode has been employed for pH detection. Electrode parameter extraction procedure is presented. Good measurement results, with 1 % error, have been attained.
2019 4th International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT), 2019
In this work an analog frontend was developed which allows to evaluate the EOG (electrooculogram)... more In this work an analog frontend was developed which allows to evaluate the EOG (electrooculogram) signals in a microcontroller and convert them into position changes of a computer mouse. A drift compensation system overcomes the most common problem of EOG measurements, the baseline drift. Different approaches for how to operate the mouse have been tested, whereby the method of controlling the mouse by giving single commands with defined movements gave the most promising results.
This paperwork presents the design and test of a microcontroller-based ECG (electrocardiogram) si... more This paperwork presents the design and test of a microcontroller-based ECG (electrocardiogram) simulator. The ECG simulator is capable of generating nine ECG signals and a calibrated square wave (1 Hz, 1 mV at Lead II). The synthesized signals are: normal sinus rhythm (60 beats per minute – BPM, and 90 BPM), sinus bradycardia (30 BPM), sinus tachycardia (120, 180 and 240 BPM), sinus rhythm with tall T wave (6EC0 BPM), ventricular tachycardia (120 BPM), and a rhythm for asynchronous ventricular pacemaker (60 BPM). The simulated ECG signals can have their amplitudes continuously varied from zero to 2 mV at lead II, through a panel potentiometer, whose knob position does not affect the amplitude of the square wave calibrated signal. The technique used to synthesize the ECG signals, a modified direct digital synthesis (DDS), appeared superior in permitting the generation of signals of very good quality and yet using a relatively small amount of memory. This latter feature enabled the us...
A precision linear positioner was design ed based on an ink-jet printer mechanism. A dc moto r, a... more A precision linear positioner was design ed based on an ink-jet printer mechanism. A dc moto r, a toothed belt, and a print head that can move along a linear guide, and a position sensor constitute the mechan ism. The position sensor is formed by a transparent plastic ribbon, t hat contains opaque vertical bars, an LED diode and a PIN photodiode mounted on a slotted arrangement through whic h t e plastic ribbon can pass, as the print head mo ves. In practice, the print head can mechanically support different w orking tools. A constant off-time chopper amplifier drives the dc motor with a programmable current, utilizing a full H-bridge and a current sensor. The amplifier rated current is 3 amperes, while it can support 55 volts. This driver allows the control of motor torque and rotation di rection. The control programs for position (and speed) run in a control board that contains an 8-bit microprocessor and dig ital input and output ports. Position sensor pulses are software d et ct...
2021 5th International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT), 2021
In this work an off-the-shelf, modern, integrated temperature, pressure and humidity sensor was i... more In this work an off-the-shelf, modern, integrated temperature, pressure and humidity sensor was interfaced to a PIC18F4550, a popular 8-bit microcontroller. A bit-banging SPI protocol was implemented. The SPI clock was set to 10-kHz to allow for relatively long distance between the microcontroller’s board and the sensor’s board. Temperature and humidity data stemming from two BME280 sensors were compared with data supplied by a commercial handheld temperature and humidity measuring instrument.
2012 Frontiers in Education Conference Proceedings, 2012
This paperwork presents a Pulse Width Modulation (PWM) drive for an electric mini-baja-type car. ... more This paperwork presents a Pulse Width Modulation (PWM) drive for an electric mini-baja-type car. The electric vehicle traction is provided by a battery-fed 1-kW three-phase induction motor. The open-loop speed control is implemented with an equal voltage/frequency ratio, in order to maintain a constant amount of torque on all velocities. The PWM is implemented by a low-cost 8-bit microcontroller provided with optimized ROM charts for distinct speed value implementations, synchronized transition between different charts and reduced odd harmonics generation. This technique was implemented using a single passenger mini- baja vehicle, and the essays have shown that its application resulted on reduced current consumption, besides eliminating mechanical parts.
Proceedings - Frontiers in Education Conference
The increased fuel economy and driveability of modern internal combustion engine vehicles (ICEVs)... more The increased fuel economy and driveability of modern internal combustion engine vehicles (ICEVs) are the result of the application of advanced digital electronics to control the operation of the internal combustion engine (ICE). Microprocessors (and microcontrollers) play a key role in the engine control, by precisely controlling the amount of both air and fuel admitted into the cylinders. Air intake is controlled by utilizing a throttle valve equipped with a motor and gear mechanism as actuator, and a sensor enabling the measurement of the angular position of the blades. This paperwork presents a lab setup that allows students to control the throttle position using a microcontroller that runs a program developed by them. A commercial throttle body has been employed, whereas a power amplifier and a microcontroller board have been hand assembled to complete the experimental setup. This setup, while based in a high-tech, microprocessor-based solution for a real-world, engine operatio...
2015 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) Proceedings, 2015
This paperwork describes the development and test of circuitry and software to enable the use of ... more This paperwork describes the development and test of circuitry and software to enable the use of Android mobile phones equipped with Bluetooth to receive the incoming electrocardiogram (ECG) signal from a user and show it in realtime on the cell phone screen. The system comprises three distinct subsystems. The first one is dedicated to condition the analog ECG signal, preparing it for conversion to the digital world. The second one consists of a microcontroller and a Bluetooth module. This unit samples the ECG, serializes the samples and transmits them via the Bluetooth module to the Android cell phone. The third subsystem is the cell phone itself. An application program written to the cell phone receives the ECG samples and suitably charts the ECG signal on the screen for analysis. The good quality of the ECG signal allows for identification of arrhythmias.
Electric Vehicles – The Benefits and Barriers, 2011
Internal combustion engine vehicles (ICEVs) have experienced continuous development in manufactur... more Internal combustion engine vehicles (ICEVs) have experienced continuous development in manufacturing technology, materials science, motor performance, vehicle control, driver comfort and security for more than a century. Such ICEV evolution was accompanied by the creation of a huge network of roads, refuelling stations, service shops and replacement part manufacturers, dealers and vendors. No doubt, these fantastic industrial activities and business have had a central role in shaping the world and, in many aspects, the society as well. Today, the number of ICEV models and applications is astonishing, ranging from small personal transport cars to a hundred passenger buses, to heavy load and goods transportation trucks and heavy work caterpillars. Modern ICE vehicles encompass top comfort, excellent performance and advanced security, for relatively low prices and, needless to say, have become since the beginning the most attractive consumer products. However, despite approximately a century-long industry and academia struggle to improve ICE efficiency, this is, and will continue to be, incredibly low. As illustrated in Fig. 1, solely circa 30% of the energy produced in the ICE combustion reaction is converted into mechanical power. In other words, approximately 70% of the energy liberated by combustion is lost. In fact and worse than that, the wasted energy of thermal motors, as ICEs may be called, is transformed into motor and exhaust gases heat. The exhaust gases are a blend formed mostly of carbon dioxide (CO 2) and, to a lower extent, nitrogen oxides (NO x), hydrocarbons (C x H y), carbon monoxide (CO) and soot. Carbon dioxide is known to block the earth's radiation emissions back into the outer space thus promoting global temperature rise-the so-called greenhouse effect. This, climate researchers say, is silently creating other global catastrophic changes, as for example, sea level rise. Air pollution in big cities is another serious problem caused by exhaust gases, which leads to respiratory system diseases, including lung cancer. Disturbing noise level is another issue related to big fleet of ICEVs in big cities. Yet, this brings about another headache for city administrators and authorities: the daily jamming, though this last nuisance might be alleviated only by mass transport systems (i.e., subways and trains). Whether none of the above listed problems ever existed, yet a challenging situation had to be dealt with urgently: the finite amount of fossil fuel available for an ever-increasing world fleet. As petrol wells vanish, this commodity price skyrockets, also motivated by political tension around production areas in Middle East. On the other hand, renewable energy www.intechopen.com Electric Vehicles-The Benefits and Barriers 2 sources, like ethanol produced from sugarcane or maize crops, are an alternative solution being tried in some countries. In Brazil, for instance, sugarcane bio-fuel is an established option, with more than two decades on the road, with ICE automobiles prepared to run interchangeably on gasoline or ethanol automatically. Any driver could choose which fuel type to use at the refuelling station, much based on their prices. There is a criticism over this solution as regards to the demands on food availability and prices, once crop fields are used to produce bio-fuels instead of food. Greenhouse effect gas generation and air pollution problems are still present though to a somewhat lower extent.
2011 Frontiers in Education Conference (FIE), 2011
This paper presents a discussion on the potential use of high tech garbage, including electronic ... more This paper presents a discussion on the potential use of high tech garbage, including electronic waste (e-waste), as a source of mechanisms, sensors and actuators, that can be adapted to improve the reality of microprocessor systems labs, at low cost. By means of some examples, it is shown that entire subsystems withdrawn of high tech equipments can be easily integrated into existing laboratory infrastructure. As examples, first a precision positioning mechanism is presented, which was taken from a discarded commercial ink jet printer and interfaced with a microprocessor board used in the laboratory classes. Secondly, a read/write head and its positioning mechanism has been withdrawn of a retired CD/DVD drive and again interfaced with the microprocessor board. Students who have been using these new experiments strongly approve their inclusion in the lab schedules.
2007 IEEE Instrumentation & Measurement Technology Conference IMTC 2007, 2007
ABSTRACT An 8051-based microcontroller tester has been designed to reduce troubleshooting time of... more ABSTRACT An 8051-based microcontroller tester has been designed to reduce troubleshooting time of the electro-hydraulic actuators (EHA) installed in fly-by-wire aircrafts. The tester algorithm first evaluates EHA pressure and position sensor signals to emit either a pass or fail message. The evaluation is based on predefined ranges of EHA pressure and position signals. Next, the instrument tests the EHA response capability -a way of dynamic response evaluation, again issuing a suitable response. The instrument proved to be reliable after being successfully evaluated in laboratory and in a real model test airplane.
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Papers by samuel e. de Lucena