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Development and fabrication of microelectromechanical systems MEMS
Koňařík, Lukáš ; Dostál, Zbyněk (referee) ; Nováček, Zdeněk (advisor)
This bachelor thesis deals with MEMS microelectromechanical systems. In the first part of the thesis the application areas of these systems are described in general together with specific cases. In addition, COMSOL Multiphysics simulations are explained in detail, as well as an enumeration of the physical principles of MEMS system technologies. In the practical part, models of an electrostatic actuator and a thermomechanical actuator are presented. The work depicts the different steps of fabrication from the initial substrate to the final structure. This process includes cutting the samples using a laser dicer, spin coating, optical lithography, depositing a conductive metal layer on an evaporator, lift-off, etching the structure using a deep reactive ion etching technique, hydrofluoric acid etching, and bonding to an electrical circuit. All steps are documented and performed in the shared laboratories of the Central European Institute of Technology CEITEC Nano. Finally, the results of the whole fabrication process are summarized and discussed.
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Acoustic target for shooting sports
Grega, Matej ; Junasová, Veronika (referee) ; Tomíček, Pavel (advisor)
Electronic scoring targets (ESTs) are designed to overcome the drawbacks of classic paper targets, particularly the inability to score individual hits in groups if they overlap and the time-consuming manual scoring process. This thesis presents the design, realization and testing of an acoustically based EST for 10 m air pistol discipline and examines the suitability of microelectromechanical system (MEMS) microphones and sealed flexural ultrasonic transducers (FUTs) as hit point localization sensors. The proposed EST is mobile and battery-powered, with built-in illumination and radiofrequency communication. The position of the hit point is calculated using a closed-form, combined weighted method based on time difference of arrival (TDOA) measurements. FUTs were used as sensors due to their filtering properties of shot and ambient noise and overall higher signal-to-noise ratio than MEMS microphones, without saturation of the output signal. The sensor positions for TDOA localization were accurately obtained using an iterative calibration method. The proposed EST prototype achieved a maximum position error of 0.39 mm, mean position error of 0.25 mm and a standard deviation of 0.10 mm for hit point localization.
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Design of a spherical microphone array
Voch, Filip ; Schimmel, Jiří (referee) ; Liska, Matej (advisor)
Spherical microphone array is one of the ways to record spatial sound. This paper proposes rigid spherical array for beamforming and mixed order ambisonics using MEMS sensors connected with TDM bus. MEMS sensors are used due to their small size. Digital output signal is transferred to external signal processor using time division multiplexing. This paper describes an approach to design of the array for beamforming using mathematical methods for node layout on a sphere and for ambisonics using spherical harmonic functions. For prototype realization there is created design with uniformly distributed microphones on the sphere. There are flexible printed circuit boards designs for connecting the microphones. Those boards are then connected to central printed circuit board, where are the signals converted to resp. from differential signal for transfer between the array and the signal processor. RJ-45 connectors are being used for this transfer. Microphones are connected to the buses by USB-C connectors. The result is framework solution including 3D model and printed circuit board designs for microphone connection. 3D model is designed in Fusion 360 software and printed circuit boards in KiCad.
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Spatial audio processing of a spherical microphone array
Tomešek, Jiří ; Honzík,, Petr (referee) ; Liska, Matej (advisor)
The diploma thesis focuses on the processing of spatial sound from a spherical microphone array, their properties, and the principles of capturing. It further explains the principles of operation of MEMS microphones and subsequent implementation. The interface between the microphone array and the computer is created using a programmable gate array along with a USB converter. The thesis outlines a suitable method for software implementation for communication, control, and interconnection of specific hardware. The implementation of individual functionalities was carried out and explained using the VHDL programming language in an FPGA. Data reception from the microphones via a TDM interface, control logic, and communication between the FPGA and the computer through an FTDI interface were implemented. Within the thesis, an application was also created in the Matlab environment for controlling the FPGA and processing data from the microphones, including a graphical user interface. The application implements the ambisonics method and a method for processing the audio signal using spatial filtering.
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Digital microphone signal processing
Vykydal, Martin ; Macho, Tomáš (referee) ; Havránek, Zdeněk (advisor)
The aim of this work is to implement digital filters into programmable gate array. The work also includes a description of the MEMS technology, including comparisons with the technology of MEMS microphones from various manufacturers. Another part is devoted to the Sigma-delta modulation. The main section is the design and implementation of digital CIC and FIR filters for signal processing of digital microphone, including simulation and verification of properties of the proposed filter in Matlab.
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Telemetry for Dragon IV Formula
Bezdíček, Jan ; Petrlík, Jiří (referee) ; Šimek, Václav (advisor)
The aim of this master's thesis was to design and construct complete telemetry system for the student formula Dragon IV constructed for international Formula Student competition. At first, the work deals with the measurement of the physical quantities, telemetry system and automotive sensors of the formula, their mutual communication and communication with the CAN bus. It also describes the procedure of hardware design including choosing right inertial sensors and a GPS module and their using in telemetry system. The work contains materials for production of two-layer printed circuit board extending the microcomputer BeagleBone Black on the inertial sensors and the GPS module. The bigger part of the telemetry system is the firmware for hardware and software for the computer user. Both written in programming language C++ and C# are included in this work as well. This user application serves for wireless receiving data from the hardware and their showing and logging. In addition this user application can be used for wireless hardware configuration. The final product is the complete telemetry system and it is suitable for selling to end customer.
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Automatic calibration of inercial sensors
Hamada, Vladimír ; Vágner, Martin (referee) ; Macho, Tomáš (advisor)
The main aim of this thesis is to design and build automatic calibration system for inertial measurement sensors. The calibration system is intended to support the development of devices with inertial measurement sensors. The great emphasis is placed on the configurability of system and for this reason all calculations are realized by Matlab system, which is well known by engineers. There is also presented design of inertial measurement unit, which is used as a~model sensor unit for calibration system development.
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The MEMS sensors usability for position detection
Bobalík, Lukáš ; Sedláček, Jiří (referee) ; Žák, Jaromír (advisor)
Within this Master’s thesis, design and construction of a strapdown inertial navigation system based on MEMS sensors is described. The thesis includes theoretic analysis of physics behind determining the position of an object based on the object’s aceleration and changes in the object’s orientation in space. Included is also an overview of mathematical methods related to the position calculation.
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Measurement of MEMS gyroscope parameter changes
Raichl, Petr ; Beneš, Petr (referee) ; Kunz, Jan (advisor)
The thesis is aimed on determination of parameters of MEMS gyroscopes with Allan variance. In the introduction, there is principle of gyroscopes described. The first part describes deterministic and stochastic parameters. Methods for determining these parameters are also described. In the practical part, stochastic parameters of two gyroscopes are determined with Allan variance. In the next part, thesis describes determination of changes of stochastic parameters after vibrations and shocks.
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MEMS based energy harvesting
Klempa, Jaroslav ; Prášek, Jan (referee) ; Gablech, Imrich (advisor)
This work is dedicated to principles of energy harvesting or scavenging from free energy around us. Energy harvesting principles are described in the first part. Following chapter is devoted to description of piezoelectricity and piezoelectric materials. Next part researches already reported results on piezoelectric energy harvesters. Following chapter shows simulations on designed structures in ANSYS® Workbench. Next the fabrication of the structures is described. Measurement are made regarding to maximum generated power.
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