ARM MCU-Based Experimental EEG Signal Generator Using Internal DAC and PWM Outputs

Electrophysiological signal generators are widely used in biomedical engineering research, biomedical education and the testing of devices in hospitals. Such signal generators are also available commercially. The EEG (Electroencephalography) signal is an electrophysiological signal which is emitted from the brain. In this study, a signal generator that produces experimental EEG signals taken from databases is proposed. The proposed signal generator reads the experimental data from an SD card with SDIO serial protocol. In addition, the PWM and DAC outputs of the microcontroller are used and examined separately to generate the signal. It has been shown that the experimental signals taken from the database can be generated by using cheap and easily accessible electronic devices. © 2022, Gazi Universitesi. All rights reserved

Spice model of current polarity-dependent piecewise linear window function for memristors

Memristor and memristive systems are nonlinear systems. It is important to model them accurately. There are different memristor models and most of the models make use of window functions. In literature, there are various window functions. Recently, a piecewise linear (PWL) window function is used to model a memristor and memristive systems. Such a memristor with a PWL window function lacks a SPICE model. Also, in literature, there is current polarity dependent window functions proposed for memristors to model polarity dependent drift speed within the thin-film memristors. In this study, an alternative current-polarity dependent PWL window function is suggested to model a memristor, a different PWL function one for each current polarity is used, its SPICE model is made in LTSpice and also its simulation results are given. Such a model can be used to model the polarity dependent drift speed within the thin-film memristors. © 2020, Gazi Universitesi. All rights reserved

Reconstructive sensing circuit for complementary resistive switches-based crossbar memories

Complementary resistive switches (CRSs) are suggested as an alternative to one-cell memristor memories to decrease leakage currents. However, their sensing is more difficult and complex than one-cell memristor memories. A method has been given for sensing their state using only DC voltages in the literature. However, in this strategy, sensing one of the logic states results in the destruction of the state and the destroyed state must be written again. To the best of our knowledge, a circuit with this sensing strategy does not exist in the literature yet. In this paper, such a circuit employing this method, which is able to read the CRS cells and able to reconstruct their data if the data are destroyed, is given. A new CRS model is also constructed in this paper and used for simulations to verify the operation of the circuit. The circuit is simulated using Simulink. We expect this circuit implementation to find use in the design and testing of CRS cells

Memristor-based series voltage regulators

Series linear voltage regulators are integrated circuits commonly used to make adjustable voltage sources. When used with potentiometers, these regulators are able to give adjustable voltage at the output. Memristor is a new nonlinear circuit element which came out in the last decade. It is able to provide electronically adjustable resistance. If a memristor is fed with a voltage over the threshold and it is not under saturation, its resistance also called memristance is dependent on the integration of its current, also called memristor charge. Memristor shows promise for different types and lots of digital and analog applications. In this paper, memristor-based series voltage regulator topologies are suggested and they are examined using parameters and simulations. Some design criteria have been given for the memristor-based series voltage regulators

Implementation of a Microcontroller-Based Chaotic Circuit of Lorenz Equations

Lorenz equations are commonly used in chaos education and studies. Simulation programs can be used to produce solutions of Lorenz equations and to examine its chaotic waveforms. However, sometimes a chaotic signal source can be needed. Such a circuit can be made using either analog or digital circuit components. Recently, a microcontroller-based circuit is suggested to obtain chaotic waveforms of Lorenz equations however only simulations are used to show proof of concept. Such a circuit needs experimental verification. In this paper, implementation and experimental verification of the microcontroller-based circuit which solves Lorenz equations in real-time and produces its chaotic waveforms are presented. Runge-Kutta method is used to solve the equation system. By using Proteus, the microcontroller-based chaotic circuit is simulated and designed. The presented design has been implemented using an Arduino Mega 2560 R3 microcontroller. The microcontroller sends the chaotic signals to the outputs of the circuit using digital-to-analog converters. The waveforms acquired experimentally from the implemented circuit match well with those obtained from Proteus simulations

Ters-Paralel Bağlı Schottky Diyot Dizisi Tabanlı Van der Pol Osilatörü Devresinin Modellenmesi ve LTspice ve Simulink Kullanarak Analizi

Van der Pol Osilatörü 1926 yılında, Philips’te çalışan elektrik mühendisi ve fizikçi Dr. Balthasar Van der Pol tarafından keşfedilmiştir. Bu osilatör çeşidinin oldukça zengin dinamikleri mevcuttur. İlk yapılan Van der Pol Osilatörü’nde bir triyot kullanılmıştır. Günümüzde Van der Pol Osilatörü, farklı yarı iletken elemanları kullanılarak yapılabilmektedir. Bu çalışmada, nonlineer devre elemanı olarak Schottky diyotlar kullanılmıştır. Bir endüktör, bir kondansatör, ters-paralel bağlı Schottky diyot dizisi ve paralel bağlanmış negatif direnç devresinden oluşan bu yeni Van der Pol Osilatörü’nün devre denklemleri türetilmiş ve benzetimi yapılarak incelenmiştir. Benzetimlerde devrenin sınır döngüsü, devre elemanlarının akımları ve devrenin gerilimi LTspice devre analizi programı ve Matlab’in Simulink paket programı kullanılarak elde edilmiştir

RF ile uzaktaki seviye değişkeninin taşınması ve analizi

Bu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır.ÖZET Anahtar Kelimeler : UART, FSK, Radyo Frekans, Seri Port, Veri Tabanı Bir analog değişkenin link edilmesi, gözlemlenmesi, verilerin kaydedilmesi, işlenerek sonuçlar çıkarılabilir bir hale getirilmesi, pek çok bilimsel ve ticari uygulamada beklenti olarak karşımıza çıkmaktadır. Bu uygulamada, bir analog değişken, radyo frekans üzerinden uzak gözlem noktasına link edilmiştir. Sistemde işlemlerin merkezinde, PIC16F877 mikrodenetleyicisi bulunmaktadır. Bu denetleyicilerin programlan assembly dilinde yazılmıştır. Gözlem noktasında alman değişken, bir bilgisayarın seri portondan uygulanmış ve visual basic' de yazılan veri tabam, veri grafikleme programı ile tekrar çağınlabilir formda saklanmıştır. xıTRANSMISSION OF LEVEL VARIABLE DATA VIA RF AND ITS ANALYSIS SUMMARY Key Words: UART, FSK, Radio Frequency, Serial Port, Data Base In this study, an analog variable obtained at a measurement point is transmitted to a remote place by means of radio frequency. The system is controlled by two PIC 16F877 microcontrollers, one of which send data by means of radio frequency transmitter and the other receive the data. The data received is send to the computer via serial port. The data obtained from remote measurement point is stored in a database and analysed by mean of a graphical user interface which was written in Visual Basic. Xl

Üç Serbestlik Dereceli Dokunsal Duyu İkame Sistemi ile El Postürü Bilgisinin Aktarılması]

12th International Conference on Electrical and Electronics Engineering, ELECO 2020 -- 26 November 2020 through 28 November 2020 -- -- 166560Motorized prostheses provides functional improvements to their users, but they lack tactile and proprioceptive senses. Different approaches have been studied to implement sensory feedback in these devices. Sensory substitution is a method for implementing sensory feedback noninvasively. In this method, a different sense (or sensory organ) is used to deliver sensory information related to a lost sense (or sensory organ). In this paper, we proposed to provide proprioceptive information to users through probes sliding on skin. The device, which is attached on the forearm, has three probes representing thumb, index and the remaining fingers. The probes are moved by linear servo motors. Six subjects were tested to differentiate six hand postures based on the information from the device. Their performance was significantly higher than the chance level. Also, there was no statistically significant systematical errors in differentiating hand postures. Therefore, the device is promising for providing proprioceptive feedback in prostheses. © 2020 Turkish Chambers of Electrical Engineers

Analog çarpici kullanarak yapilmiş lineer sürüklenme hizli Ti02 memristör (hafizali direnç) taklit devresi]

2010 7th National Conference on Electrical, Electronics and Computer Engineering, ELECO 2010 -- 2 December 2010 through 5 December 2010 -- Bursa -- 83834Memristors or charge-controlled memristive systems , are not available for experimental studies in market. In literature, emulators which mimicks memristor behaviour for studying and teaching of memristor do exist. In this work, for the first time in literature, a Ti02 memristor emulator is made by an electronic circuit with an analog multiplier. Using hysteresis and saturation phenomena, it is shown that this emulator can mimick Ti02 memristor with linear dopant drift speed well

SPICE Model of Current Polarity-Dependent Piecewise Linear Window Function for Memristors

Memristor and memristive systems are nonlinear systems. It is important to model them accurately. There are different memristor models and most of the models make use of window functions. In literature, there are various window functions. Recently, a piecewise linear (PWL) window function is used to model a memristor and memristive systems. Such a memristor with a PWL window function lacks a SPICE model. Also, in literature, there is current polarity dependent window functions proposed for memristors to model polarity dependent drift speed within the thin-film memristors. In this study, an alternative current-polarity dependent PWL window function is suggested to model a memristor, a different PWL function one for each current polarity is used, its SPICE model is made in LTSpice and also its simulation results are given. Such a model can be used to model the polarity dependent drift speed within the thin-film memristors