Kemal Karagöz

My role

I was responsible for the project’s mathematical modeling, electronic design, embedded software, prototyping, and experimental testing. I carried out the technical development from transmitter and receiver circuit design through PCB manufacturing preparation, component assembly, software development, and measurements. I continued working on the prototype after graduation until October 2024.

Electronic design and prototyping

On the transmitter side, I worked on signal generation and modulation circuits to drive the ultrasonic transducers. On the receiver side, I designed circuits to amplify, filter, and condition the reflected signal for reading by the microcontroller. I simulated selected parts of the circuitry in LTspice.

Using Altium Designer, I created the schematics and PCB layouts and prepared the manufacturing files and bill of materials. I populated and soldered the manufactured boards. I also designed an additional connection board in KiCad to organize the connections between the main board and the microcontroller.

Mathematical modeling and embedded software

I used Python to study array element placement, beam patterns, and phase and time-delay calculations. I modeled the relationships between transmitter trigger timings to investigate scanning in different directions.

On the ESP32, I developed software for transmitter control, PWM generation, receiver signal acquisition, and distance measurement. I incorporated the phase and delay calculations into the embedded software and carried out beam-steering trials with different transmitter arrangements.

Testing and troubleshooting

I tested the prototype in stages, covering the power circuitry, signal generation, modulation, and transmitter and receiver circuits. I used an oscilloscope to examine signals at different points in the circuit and compared the observed behavior with the expected results.

At one stage, the receiver signal was visible on the oscilloscope but could not be read by the microcontroller. I investigated the power supply conditions and the software’s execution flow. I tested the transmitting and receiving tasks on separate microcontrollers to investigate the problem and revised the distance-measurement algorithm. I then carried out distance-measurement experiments and scanning trials at different angles using an eight-transmitter arrangement.

Findings and areas for further development

The experiments helped me understand how saturation and thresholding in the receiver circuit affected the preservation and interpretation of weak signals. Limitations in the available measurement equipment restricted direct verification of the phase relationships between channels. I assessed the results within these constraints and treated the work as an experimental prototype.

I now revisit the project in technical blog posts, explaining the methods I used, the problems I encountered, and the design decisions I would approach differently. These reflections also provide a foundation for Sonar V2, which I plan to develop.

Tools and technologies

Altium Designer, LTspice, KiCad, Python, ESP32, Arduino IDE, ultrasonic transducers, analog signal conditioning, PWM, and oscilloscope measurements.

My role

I carried out the modeling, circuit setup, simulations, and reporting independently. Throughout the work, I received technical feedback and guidance from my optoelectronics instructor.

Electromagnetic modeling

I recreated the sensor geometry described in the paper in CST. I examined the frequency response and resonant behavior of the model, which included the UGCPW structure and NS-SRR elements, using the simulation outputs. I incorporated the model into a simulation setup that allowed me to study it together with related RF circuits.

Evaluation with RF circuits

I examined the sensor model within a circuit arrangement containing a voltage-controlled oscillator (VCO), a low-noise amplifier (LNA), and a 3 dB power divider. Using the divider, I observed signals in different circuit branches and evaluated the sensor output alongside the signal obtained through the amplifier.

For the VCO section, I used a circuit model available in the CST library. This allowed me to examine the sensor’s electromagnetic model together with signal generation and amplification functions within the same study.

Scope and experience gained

The project covered electromagnetic and circuit simulations in CST. It did not include physical fabrication or laboratory measurements. I evaluated the results within the conditions of the simulations.

This work gave me experience in translating a published design into a numerical model, setting up simulations, examining RF circuit blocks together, and documenting the results in a technical report.

Tools and technologies

CST Studio Suite, electromagnetic modeling, RF circuit simulation, UGCPW, NS-SRR, VCO, LNA, and power-divider circuits.

My role

I worked with my project partner on requirements analysis, control scenarios, PLC programming, HMI/SCADA applications, and simulation. We jointly reviewed and developed all parts of the project.

PLC control logic

Using Siemens TIA Portal, we developed control logic in LAD, FBD, and SCL for a CPU 1214C from the S7-1200 family. We structured the plant’s startup, normal operation, and shutdown processes as interconnected control steps.

We defined the prerequisites for starting the turbine and generator, cooling-water checks, and commands associated with excitation and automatic synchronization. We created separate control sequences for normal shutdown, fault-related shutdown, and emergency shutdown.

Auxiliary systems and fault scenarios

Alongside the main generating unit, we included control of auxiliary systems such as drainage pumps, cooling-water pumps, and air compressors. We defined operating conditions based on water level, pressure, speed, and equipment status.

We implemented alarm, operator acknowledgment, and reset logic for electrical and mechanical faults. The control scenarios specified the conditions under which equipment could operate and when it needed to stop.

HMI, SCADA, and simulation

We developed HMI and SCADA applications to monitor process states and pass operator commands to the control system. We linked PLC variables, equipment states, and alarm information to monitoring and control functions.

Through simulation, we evaluated control sequences under different operating conditions. We considered the PLC, HMI, and SCADA components together and worked on the interaction between the control software and operator interfaces.

Experience gained

This project gave me experience in translating a real facility’s requirements into automation software, considering interconnected equipment as a complete system, and developing control scenarios for different operating states. It also gave me practice in developing and reviewing the different parts of a substantial automation project with a teammate.

Tools and technologies

Siemens TIA Portal, Siemens S7-1200 / CPU 1214C, LAD, FBD, SCL, HMI, SCADA, sequential control, alarm logic, and interlocks.

Our aim was to examine how the rocket’s geometry affected its flight performance and identify suitable designs under defined environmental conditions and design constraints. We combined design of experiments (DoE), flight simulation and stochastic optimization to compare different designs systematically.

As part of the study, 505 design scenarios generated using DoE were simulated in OpenRocket. MacroRecorder was used to automate repetitive data entry and simulation tasks. The resulting flight performance data was recorded alongside the design variables and formed the basis for the mathematical modelling work.

Using Wolfram Mathematica, we developed nonlinear regression models to represent the relationships between design variables and flight outputs. The models’ predictive performance was evaluated by splitting the data into training and test sets. These models were then used in stochastic optimization studies based on the defined objectives and constraints.

For the avionics system, we designed our own electronic board as a team using Altium. The system included STM-based hardware, a Raspberry Pi, a six-axis motion sensor and a pressure sensor. We also developed a ground station application in C# and used it to receive data from the system. As the avionics lead, I was actively involved in the work on the board design, sensors and ground station software.

We also worked on the physical production of the rocket, which we built with sponsorship support from Şişecam. However, we were unable to carry out flight tests. Our assessments of flight performance therefore remained based on simulation and mathematical modelling results.

This project gave me experience in managing a development process from building a multidisciplinary student team through to design, analysis and physical production. It also gave me practical experience in coordinating electronics, software and mechanical work, using simulation results to inform design decisions, and maintaining technical coordination within the team.

I created the 3D design for a model vehicle approximately 35–40 cm long. I had the parts cut from acrylic, assembled the vehicle body and built an Arduino-based control system. By placing several alcohol sensors in different parts of the vehicle, I investigated where alcohol was detected. This arrangement allowed me to experiment with distinguishing alcohol originating from the driver’s area.

I used a distance sensor and a camera to detect the model vehicle’s surroundings. Image processing ran on a computer: I transferred the camera feed to a graphical interface I developed in Visual Studio and applied basic image processing operations. This was a simple, experimental approach to environmental perception developed as part of a high school project.

I implemented two main scenarios in the control software. When alcohol was detected while the vehicle was stationary, the system prevented it from moving. When alcohol was detected while it was moving, the vehicle pulled over to a suitable area on the right and a message was sent to close contacts. I successfully demonstrated movement prevention, pulling over and message delivery in tests with the model vehicle.

For the mobile component, I developed a phone application using MIT App Inventor and established Bluetooth communication between the application and the vehicle. This brought sensor-based detection, vehicle control, computer-based image processing and mobile communication together in a single prototype.

With this project, I won first place in physics in the Malatya regional round of the 2017 TÜBİTAK High School Students Research Projects Competition. I qualified for the national finals, where I received an Encouragement Award in physics.