The biocompatible devices suitable for recycling and biodegrading can be achieved with organic materials in nature. In this work, a biocompatible capacitive humidity sensor is presented to reduce the amount of electronic waste and contribute to the sustainability of natural resources and the future. The sensor consists of three layers. The first layer is the processed intestine layer of cattle. Biocompatibility is achieved with this layer. In addition to being a highly absorbing tissue, the intestine has been used for centuries for the long-term preservation of meat-based food. Correspondingly, the developed sensor is found to be more durable and long-lasting than other natural-material-based humidity sensors in the literature. The other layers of the sensor are interdigitated copper electrodes and a 0.2-mm-thick thin-film strip. A thin-film strip increases mechanical strength as well as flexibility. The developed sensor prototype was subjected to various tests in the humidity range of 20%-90%. In these tests, the hysteresis characteristic of the sensor, its response-recovery time, and its long-term stability and short-term step responses were examined. Moreover, as a possible application in medicine, the sensor can be used to detect breathing cycles. The sensor's response and recovery times were measured as 8.72' and 4.47', respectively, possibly attributed to the stabilization of our test setup, while the sensor successfully detected deep, normal, and fast breathing. Despite being kept in an uncontrolled environment, the sensor continued to operate consistently for breath measurements after 56 weeks, which is more than a year.

In the time of global chip crisis, it is clear that alternative electronic solutions are necessary; particularly for capacitive rotary encoders, or similar capacitive sensors where demodulation techniques are extensively used. In this work, a discrete analog switch based circuit solution is proposed for the capacitive rotary encoders for the first time in the literature to the best of our knowledge. A 3-layer uniquely designed capacitive encoder prototype is used as a capacitive sensor. The analog switch with OPAMP based demodulation configuration designed for this work is both cheaper and it works at higher frequencies than the analog multiplier configuration. Also, unlike ASIC, it does not require high-tech for production. With the established test setup; noise, smallest perceptible capacitance, nonlinearity and temperature analyses of the circuit were made and competing results were achieved. The noise levels in terms of degree and voltage are measured as 0.0063° and $36.62~\mu \text{V}\sqrt {\text {Hz}}$ ; respectively. Minimum measurable capacitance achieved with the discrete analog circuit is 2.54 aF $\sqrt {\text {Hz}}$ . Nonlinearity was found to be 0.29% which is highly correlated with the mechanical misalignments of the capacitive encoder. Although this particular study is carried out on capacitive encoders, the proposed circuit solution can be used for similar types of sensors.

This article presents a new capacitive proximity sensor circuit based on capacitance-frequency (C-F) conversion for non-contact measurement (on-off) of grain products. In the literature, mostly contact capacitive sensors are used for grain measurement. The proposed new approach aims to make a non-destructive measurement with a non-contact sensing feature. However, the low dielectric constants of grain products and the fact that the sensor does not come into contact with the product make things difficult in terms of measurability. It is therefore intended for the sensor electronics to detect low capacitance changes. With the proposed new design, low capacitance changes are detected non-contact with the help of the electrode in front of the sensor and it changes the frequency of the output signal. This frequency change is measured by a microcontroller (MCU) and a digital output is given. Simulation analyzes and experimental studies related to the sensor were carried out. For experimental studies, cereal products such as corn, wheat, bran, and razmol were used and the results are reported

In this paper, design and prototyping of a novel, high resolution, and low-cost capacitive encoder were presented. Detailed analysis showed that the number of poles on the rotor should be as high as possible to keep the gain high and to reduce the non-linearity. Moreover, contrary to the common intuition, inter electrode gap is found to have an optimum non-zero value, corresponding to a particular number of poles, in order to maximize the gain. However, increasing number of poles brings practical problems due to manufacturing limits and digital electronic frequency load. As the electronics, micro-controller based digital signal processing is used to keep the cost as low as possible. With miniaturizing the encoder geometry as a design target, the number of plates were increased to three to increase the capacitances. One prototype, which is around 3 cm in diameter could be successfully mounted to an industry oriented DC motor and tested. The tests of this miniaturized encoder showed non-linearity error of 0.12% and resolution of 0.02 degrees. One source of the non-linearity error is the DC motor itself, and we believe that with a better setup, the error could be measured to be even better. (C) 2021 Elsevier B.V. All rights reserved.

Kapasitif enkoder teknolojisi manyetik ve optik enkoder teknolojilerine kıyasla daha güncel ve günümüzde halen geliştirilmekte olan bir açısal pozisyon algılayıcı teknolojisidir. Çeşitli özelliklerde ve farklı bileşenlere sahip kapasitif enkoderler bulunmaktadır. Yenilikçi ve yüksek performanslı kapasitif bir enkoderin geliştirilebilmesi için mevcut kapasitif enkoderlerin ayrıntılı bir şekilde irdenlenmesi ve sınıflandırılması gerektiğinden bu çalışmada genel bir kapasitif enkoder mimarisi tanımlanarak kapasitif enkoderler için detaylı bir sınıflandırma verilmiştir. Sunulan mimari; sinyal işleme ön devresi, algılayıcı mekaniği ve sinyal işleme son devresinden oluşmaktadır. Sinyal işleme ön devresi kapasitif enkoderin tetikleme sinyal devresini, sinyal işleme son devresi kapasitif enkoderin demodülasyon devresini içermektedir. Burada sağlam bir algılayıcı mekaniğin belirlenebilmesi için kapasitif enkoderler detaylı bir şekilde sınıflandırılmıştır. Sınıflandırma işlemi kapasitif enkoderlerin plaka sayılarına, plakalar üzerine yerleştirilen elektrot dizilişlerine ve rotor plakaların malzemelerine göre yapılmıştır. Sınıflandırma sonucunda sağlam bir algılayıcı mekaniğine karar verilmiştir. Algılayıcı mekaniğindeki bileşenler çeşitli analizlerle belirlenip bilgisayar destekli tasarım programlarıyla tasarlanmıştır. Tasarlanan mekanik bileşenler üretildikten sonra sunulan algılayıcı mekaniği kurulmuştur. Kurulan algılayıcı mekaniği için de bir ön tasarım süreci işletilmiştir. Algılayıcı mekaniği kurulduktan sonra uygun fiyatlı bir test düzeneğinde test edilmiştir. Bu çalışmayla, geliştirilmekte olan yenilikçi ve yüksek performanslı kapasitif enkodere sağlam bir algılayıcı mekaniği kazandırılmıştır.

In this study, transimpedance amplifier based front-end circuits which can be employed to measure small capacitances were designed, analyzed and simulated using analog electronic circuit simulator. The front-end circuit converts the current flowing through the measured capacitance into a modulated voltage value which contains information regarding the desired capacitance. The frequency-domain, time-domain, stability and noise analyzes were carried out numerically and in simulation environment using a circuit simulator. The analytical, numerical and simulation results can be used to design optimized, precise and stable transimpedance amplifiers with low-noise value. The measured capacitance value was 10 pF which is low enough to simulate various real-world applications. Three commercially available, off-the-shelf operational amplifiers with different peripheral passive components were employed for computer based analysis. The designed transimpedance amplifiers are suitable to connect with capacitance extraction circuits which use analog or digital demodulation techniques.

The moving plates of the capacitive encoders are called rotors and the fixed plates are called stators. In this study, the effects of the rotor plates on capacitive measurement for capacitive encoders are analyzed. Encoders are used in angular position measurement. They can be preferred especially in most applications where rotational motion occurs in the robotic application areas. The application areas of the encoders can be further extended with the capacitive encoder technology. The capacitive encoder technology is based on measuring the capacitances between the encoder plates. As the capacitances vary depending on the overlapping areas of the encoder plates, the shapes and the patterns of the encoder plates directly affect the capacitive measurement. Therefore, the capacitive encoder plate selections must be made correctly. There are very few studies on the selection of the capacitive encoder plates. It is seen that the current studies generally continue on a similar type rotor patterns. Various rotor plates are proposed in this study for the capacitive encoder that we are in the development process. After the rotor patterns are expressed mathematically and the capacitive encoders using rotors with these patterns are compared. The comparison process was made by calculating the equivalent capacitance between the proposed capacitive encoder plates. The effects of rotors with different materials and patterns on the capacitive measurement were investigated. Thus, a contribution was made to the effective development of similar capacitive sensors.

Arktanjant fonksiyonu güç sistemlerinde, AC devrelerdeki analizlerde, enkoderlerde açı ve hız hesabında sistemlerin izlenmesi ve kontrolü için vazgeçilmez bir parçadır. Bu tür kontrol uygulamaları çoğunlukla mikrodenetleyicilerde yapılmaktadır fakat mikrodenetleyicilerin işlem kapasiteleri kısıtlıdır. Arktanjant fonksiyonu bir mikrodenetleyici içerisinde seri açılımı yöntemi ile hesaplanmaya çalışılırsa hem çok fazla işlem gücü gerekir hem de uzun zaman harcar. Ayrıca seri açılımı yönteminde hassasiyetin artması için daha fazla terim gerekir ve bu işlem yoğunluğunu daha da arttırır. Fakat arama tabloları ve CORDIC algoritması kullanılarak bu işlemler hem daha hızlı hem de bit düzeyinde kaydırma, toplama ve çıkarma gibi basit işlemlerle yapılabilmektedir. Bu gibi bit düzeyindeki işlemler ortalama bir mikrodenetleyicinin rahatça yapabileceği işlerdir. Bu çalışmada kapasitif rotary enkoderlerde rotor açısı ve hız hesabı için CORDIC algoritması kullanılmış ve bu işlemler ARM çekirdeğini kullanan bir mikrodenetleyicide gerçekleştirilmiştir. Sonuçlar hazır matematik kütüphanelerindeki arktanjant fonksiyonu ile kıyaslandığında CORDIC algoritmasının 0.0036” hassasiyet ile aynı işlemleri atan2 fonksiyonundan yaklaşık 9 kat ve atan2f fonksiyonundan 2 kat daha hızlı yaptığı gözlemlenmiştir.

Determining the moisture content of grain products is very important for the quality, yield and cost of the production line. For this purpose, in-line or off-line, destructive or non-destructive measurement methods are widely used. In this study, an in-line, non-destructive capacitive humidity sensor is designed using analog switching based synchronous demodulation technique. The sensor system is tested under laboratory conditions and then installed in a real flour production factory. The results are tested and compared with reference humidity measurement systems. As analog switching based synchronous demodulation technique used in this study is an effective, cheap, and robust technique for achieving high signal-to-noise ratio (SNR); and a proper front-end circuit also minimizes the effect of temperature change on the sensor output, and effective, low cost sensor system is achieved. The sensor, while measuring the same product for long periods, shows almost no output change during day and night. Moreover its output for different type and humidity products show very similar values compared to reference systems. Hence, the designed capacitive moisture measurement system is shown to be a good non-destructive in-line sensor alternative in terms of cost and performance.

This paper presents a lossy capacitance measuring circuit which is based on analog lock-in detection technique. Lossy capacitance can be modelled as a pure capacitor connected in parallel with a resistor. The measurement circuit mechanism consists of an excitation signal to drive the lossy capacitance, a transimpedance amplifier to produce a voltage, and a lock-in detection circuit to extract lossy values of capacitance. The lock-in detector multiplies its input with a square wave using switches and filters out high frequencies to give a DC output that is actually in proportional to the measured values. A field programmable gate array is employed to generate direct digital synthesis based sinusoidal excitation signal to generate reference signals required for demodulation and to measure the output of lock-in detection. The phase shift between the excitation signal and reference signals is controlled accurately in digital domain. Thus, due to the phase mismatch, errors are properly reduced. Also, analog phase shifter and analog switch-driving circuits are no longer required. Three different lossy capacitors realized using discrete components are simulated and tested. The maximum relative error is 1.62 % for the resistance measurement and 6.38 % for the capacitance measurement.

This study aims to optimize certain performance parameters of an analog front-end circuit for capacitance measurement. The front-end circuit produces an output voltage in proportional to the measured capacitance. This output voltage should be demodulated by means of digital or analog demodulators to extract the capacitance information. In order to obtain an accurate and precise capacitance measurement, the front-end circuit’s performance parameters must be optimized carefully. In this paper, a transimpedance amplifier consisting of an operational amplifier with a feedback resistor and a feedback capacitor is employed as the front-end topology. The transimpedance amplifier’s gain, settling time and outputreferred total noise are the performance criteria which form a multi-parameter optimization problem. These performance criteria primarily depend on the values of the feedback resistor, feedback capacitor and operation frequency. Grey Wolf optimizer Algorithm is used to find these values optimally. To verify the algorithm’s results, SPICE based simulations are carried out for two capacitance measurements.

A new micromechanical device is proposed which is capable of modulation, demodulation and filtering operations. The device uses a patented 3-mass coupled micromechanical resonator which dynamically amplifies the displacement within a frequency range of interest. Modulation can be obtained by exciting different masses of the resonator with the data and the carrier signals. Demodulation can be obtained similarly by exciting the actuator with the input and carrier signals at the same time. With the help of dynamic motion amplification, filtering and signal amplification can be achieved simultaneously. A generic design approach is introduced which can be applied from kHz to MHz regime frequencies of interest. A sample mixer design for an silicon on insulator-based process is provided. A SPICE (Simulation Program with Integrated Circuit Emphasis)-based electro-mechanical co-simulation platform is also developed and the proposed mixer is simulated.

Rotary encoders, which are mainly used to feedback the angle of the robot arm to the robot controller system, are widely used in industrial and robotic applications. While optical and magnetic rotary encoders are dominant in the market, capacitive rotary encoders are also gaining interest for their simple design, ability to miniaturize and being absolute encoders insensitive to magnetic field variations. In this study, a new economical capacitive rotary encoder based on analog synchronous demodulation is developed. Analog synchronous demodulation technique is used for the first time in the literature as far as known to the authors for capacitive rotary encoders. It is chosen as it is quite robust, simple and economical. A compact mechanical body is developed by 3D printing. After packaging, the sensor is fixed to a motor for testing. The developed encoder shows 2880 pulse/rotation resolution and repeatable output under different temperature environments.

In this work, we present the thermal behavior of a glow plug examined with thermal impedance modeling. The circuit model is based on the analogy of thermal and electrical domains and expresses the glow plug used in diesel engines to preheat the air-diesel fuel mixture. In this study, the circuit design, implementation, and simulation of a glow plug for diesel engines are illustrated. In order to verify this thermal model, 2 different glow plugs are produced. The test results of the glow plugs produced in this study show complete agreement with the simulation results. It is thought that this circuit-based model will provide fast and reliable simulations and will be beneficial in the industry for addressing different glow plug needs.

We present a successful integration scheme of a backside illuminated 1024×1024 pixel sensor array, flip chipped on top of a ROIC with 10μm diameter Indium micro bumps, where the pixel pitch is 22.5μm. Backside illumination results, as compared to front side illumination, in a large gain in quantum efficiency because no incoming light is lost in the metal and dielectric layers. At the other side however, backside illuminated imagers requires more complex post processing because the detector array has to be thinned down to 30μm or less. Surface treatment reduces surface combination and lead to an improvement of the quantum efficiency of the device. Any damage induced at the backside of the imager is detrimental for the quantum efficiency since defects act as recombination centers for the light generated electron-hole pairs. In the end, all process optimizations on the hybrid backside illuminated imager device lead towards a quantum efficiency of 80–90% (over the visible spectrum). Next to the discussion on the critical steps (such as wafer thinning on carrier, wafer flip, cleaning), we introduce a novel backside alignment strategy to avoid using pyrex substrate as temporary carrier for thinning. Pyrex is namely not compatible in a high-end Si process environment due to its fragile nature. It is also shown that through introduction of a high aspect ratio pixel separating trenches, inter pixel electrical crosstalk can be avoided. Finally an alternative micro bump formation by means of CuSn bumps is presented.

This paper presents a review on using MEMS based mirror arrays to achieve maskless lithography in order to eliminate mask costs in the micro fabrication processes.With the advanced technology nodes, it becomes more and more costly to produce the lithography masks.Especially with the extreme ultraviolet lithography technique, the necessity to use maskless lithography becomes more obvious.Several universities and companies fabricated tilting mirror style or piston style mirror arrays to propose a solution to maskless lithography processes.

This paper evaluates the performance characteristics of a new miniaturized lateral capacitive accelerometer with a high bandwidth as well as a high sensitivity, utilizing a low thermal budget SiGe MEMS technology. The accelerometer combines a 4 mu m SiGe structural layer thickness with a small capacitive sensing gap of 500 nm, leading to an improvement in sensitivity along with large bandwidth and a reduction in overall dimension compared to conventional accelerometers, which have gaps in the order of 1 mu m. The accelerometer studied here is targeted for a maximum operational range of +/- 2g. (C) 2012 Elsevier Ltd....Selection and/or peer-review under responsibility of the Symposium Cracoviense Sp. z.o.o.

This paper presents a new family of multi-mass coupled resonators that can provide robust operation and dynamic motion amplification at the same time. The basic resonator block consists of three masses coupled to each other, where the first mass is the driver unit, the second mass transfers the dynamic energy and the third mass is the final oscillating mass. This basic block can be further enhanced to a more-than-three-mass system to create a multi-mass system to improve the amplification. In order to analyze this multi-mass system, a generic analytical model is derived which is valid for a finite number of masses. This analytical model is verified for the three mass system using FEM simulations. A detailed modeling of a sample three-mass micro-resonator is provided demonstrating the robust operation and the mechanical amplification. Finally, a five-mass system is proposed to improve the mechanical amplification.