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Prepare LORA Physical Layer for Testing in Low Earth Orbit on a CubeSat
Get PDFThis project is a collaboration with OWL Integrations, a company that specializes in adaptable, low-cost communication systems. OWL has developed a board specifically designed for space applications called the Space Quacker Advanced Development (SQuAD), which is an adaptation of their existing board called the Quaker Advanced Development (QUAD).
This project focuses on testing the existing SQuAD board design to make sure that it is flight-ready for deployment on Cal Poly CubeSat’s satellite, SAL-E. To achieve this, the project must ensure compatibility with Low Earth Orbit (LEO) conditions by testing the integrated high-power long-range (LoRa) receiver and enhanced hardware to meet the rigorous environmental requirements. Additionally, the project includes integrating the SQuAD board with the CubeSat and testing the software to make sure that they can communicate with one another. Finally, the project will include ensuring that the CubeSat ground station can transmit LoRa packets, verify signal reception on the SQuAD boards, and edit firmware for the SQuAD board to relay data through the CubeSat. The significance of this project is to provide a low-cost, reliable satellite communication system, which can be used in many different applications, like disaster recovery and scientific data collection
A Battery Charging System from a Spinning DC Generator
Get PDFThis project presents the design and construction of a battery charging system powered by a wind energy emulator. An adjustable-speed DC motor drive coupled to a DC generator was used to imitate a wind turbine rotating at different speeds, supplying a variable DC voltage to a custom PCB with an LTC4020, a four-switch buck-boost converter and battery charger. The converter steps up or down the input voltage, ranging from 12 to 24 volts, to safely charge a lithium-ion battery using a constant current constant voltage charging cycle (CC/CV). The system highlights the practicality and increasing use of renewable and wind-powered energy for household energy storage, aligning with the growing popularity of sustainable and off-grid power solutions. Hardware development centered on a custom-designed PCB made to operate under the converter’s system requirements, with key parameters such as inductor sizing, current sensing, and feedback control calculated from the LTC4020 datasheet design equations, further validated through LTSpice simulation. System protections, such as for overcurrent, were implemented to ensure reliability under different wind speed conditions. Final testing demonstrated consistent delivery of the desired constant current charging to the battery, confirming the converter’s effectiveness for renewable battery charging applications. This work serves as a foundation for further expansion toward real-world wind turbine integration and scaled energy storage systems for residential use
Reverse Engineering Bring Up And Profiling Of Multi-FPGA Systems
Get PDFFPGAs have long been used for prototyping and verifying high-speed digital designs in industry and in academic research. As ASIC designs have grown in complexity and size, prototyping those designs on FPGAs has required multiple FPGAs that sometimes span multiple servers. Western Digital donated multiple FPGA-based systems to Cal Poly in 2023. These servers contain multiple high-end AMD FPGAs that are ideal for prototyping large high-speed digital designs, however the full documentation on how to use the servers and how the servers work was not provided. The servers did not come with any information on how to program the FPGAs, how to use the software that was preloaded onto the systems, or how to interact with many of the hardware interfaces. Multiple faculty members have projects that could benefit from prototyping on large FPGA systems, however none of the faculty at Cal Poly know how to program the FPGAs, or utilize the high-speed communication links between the FPGAs. This thesis lays out the debugging and reverse engineering steps that were taken to understand and bring up these servers. It specifically details how to program the FPGAs, how to use the debug interfaces, how to program the onboard clock generators, and how to use the high-speed interconnects between the FPGAs and between the systems. It also details several example designs for verifying and profiling these interconnects and characterizes these interconnects in terms of throughput and latency. Finally this thesis generalizes the takeaways from reverse engineering these systems to steps that can be taken when reverse engineering complex hardware/software systems
HI-TRAC Camera Jig
Get PDFUranium fuel assemblies are stored upright in an underwater container inside the spent nuclear energy fuel pool at Diablo Canyon. The engineers and in-service-inspection team all work together to safely locate this container inside the pool on pins so it is guaranteed safe before they begin loading it with spent uranium fuel rods. The Operators currently employ the use of a zip-tied camera jig that is lowered into the pool along with the tank (called a HI-TRAC) to ensure it is oriented correctly in the pool. This camera jig is in desperate need of re-vamping and re-designing to optimize efficiency and limit the amount of time the inspection team is exposed to harmful radiation doses
Large Backflow Check Valve Life Cycle Test Stand
Get PDFBackflow preventers are plumbing devices containing internal check valves used to prevent cross-contamination between downstream contaminants and potable water supply. Zurn Wilkins needs a life cycle test stand to mechanically force open check valves submerged in contaminated water and verify check performance. The stand needs to be modular to work with a range of check types and sizes.
Zurn Wilkins is the primary stakeholder for this project. Secondary stakeholders include commercial and residential building owners, contractors, and water utility companies, who rely on their products for safe and efficient water management. The team for this project consists of four Cal Poly mechanical engineering students
Design, Modeling, and Testing of a Novel Inductor for Electric Vehicles: Iron Nitride Soft Magnetic Composites
No full textThis multi-year project focuses on the design, modeling, and testing of novel inductors for electric vehicles (EVs) using iron nitride (IN) soft magnetic composites (SMCs). This work is a continuation of previous research, with the overarching goal of enhancing EV efficiency by developing inductor cores with improved magnetic properties, leveraging IN\u27s competitive magnetic characteristics.
This year, the project concentrated on refining fabrication processes to optimize relative permeability (μr) and effective IN concentration. Investigations included various mixing vessels, the application of vibration during powder settling, and different pressing methods and pressures across initial IN concentrations of 75, 80, and 85 vol%. Inductance and AC resistance measurements were performed, and the COMSOL™ Multiphysics model underwent significant refinement.
Key findings indicate that despite these processing modifications, the project did not consistently achieve higher effective IN concentrations or relative permeabilities than previous work, with effective IN concentration generally plateauing around 65 vol%. The 75 vol% initial IN concentration group, however, showed the highest meanμrand theoretical density. Cold mixing extended the epoxy\u27s working time but resulted in reduced magnetic performance. Vibration-assisted settling generally led to higher effective IN concentrations compared to hand tamping, and double pressing at elevated pressures (190 MPa followed by 120 MPa) yielded the highest mean relative permeability and percent of theoretical density. Increasing the initial IN concentration beyond 75 vol% did not translate to a higher effective IN concentration. An alternative approach using 3D-printed shells for a theoretical 100 vol% IN core proved less effective, exhibiting reduced magnetic performance due to low packing density and increased eddy current losses in the absence of an insulating binder.
A significant advancement was the refinement of the COMSOL™ model. The corrected model now more accurately accounts for realistic winding geometries and addresses previously identified artificial air gaps, greatly improving its ability to predict measured inductance. This enhanced model is validated for future use in simulating and validating experimental results for toroidal inductors
A Manufacturing Process for Interdigitated Microelectrodes on Glass Wafers
Get PDFThis study presents work done to optimize the process parameters to produce interdigitated electrodes on a borosilicate wafer. Using designed experiments and statistical analysis, the error in pattern transfer was minimized using for key process steps including exposure time, develop time and post exposure bake duration. Similarly, statistical analysis was used with profilometry data to fine tune the develop times. Qualitative analysis was used to assess thin film deposition. The resulting process produced wafers with improved pattern transfer and adequate film adhesio
The Application of LiDAR for Classifying Wildland Fuels
Get PDFAccurate vegetation classification is critical for modeling wildfire behavior, particularly in fire-prone ecosystems where fuel type influences fire spread and intensity. This study evaluates the effectiveness of UAV-based aerial LiDAR, supplemented by multispectral imagery, for classifying grass, shrub, and tree vegetation types across a grass-dominated landscape. Using canopy height thresholds, vertical profile analysis, LiDAR predictions were compared against field-verified vegetation observations at 80 survey points. Results showed that LiDAR classified grass with high accuracy but was less reliable for detecting shrubs and trees, especially under canopy cover. Misclassifications were most common beneath tree canopies and in areas where low-stature shrubs were present, highlighting structural limitations in the current model. The study also explores the benefits of integrating multispectral data to improve vegetation differentiation, particularly where structural information alone is insufficient. Findings suggest that while LiDAR is effective for mapping dominant fuel types, future improvements—such as expanding shrub height thresholds and enhancing sub-canopy detection—are necessary for broader application in wildfire risk modeling
Statistical Time-History Response of Mid-Story Isolated Structures in Linearized Elastic Conditions
Get PDFThis study presents a statistical analysis of the seismic demand of mid-story isolated structures in linearized elastic conditions. The assumed earthquake database consists of 228 ground motions recorded in California from earthquakes with magnitudes greater than 6. A three-degree-of-freedom modeling approach is adopted, and the seismic demands of the substructure, superstructure, and isolation system are determined for varying isolated mass and stiffness ratios. The seismic demand of mid-story isolated structures at the isolation level is expressed in terms of the response of an idealized isolated superstructure supposed to be on the ground, while the demands on the substructure and superstructure are expressed relative to their respective fixed-base counterparts. The results are used to validate the analytical predictions obtained through modal analysis procedures and to highlight areas for future improvement. The expressions of the normalized demands are implemented in a practice-oriented design framework that enables the seismic demand of mid-story isolated structures to be quantified based on the independent responses of the substructure and the isolated superstructure
Density-Dependent Habitat Selection and Home Range Sizes in a Recovering Population of Island Foxes (Urocyon Littoralis) on Santa Rosa Island, California
Get PDFUnderstanding factors that affect how animals select their home ranges is critical for proper species management, especially for threatened and endemic species. Density-dependent factors can be particularly difficult to understand because studying them requires large fluctuations in population size. The island fox (Urocyon littoralis), endemic to the California Channel Islands, has experienced dramatic fluctuations in population size making it an excellent candidate for studying the effects of density on home range size and habitat selection. In 2009, researchers on Santa Rosa Island took advantage of this “natural experiment” to document fox home ranges and habitat selection at a low population density. The fox population has since recovered, which provided an ideal opportunity to examine the same population under dramatically different densities to determine the effect of population density on home range size and composition. We collected GPS data from foxes in a high-density fox population on Santa Rosa Island and directly compared the resulting home range size, overlap, and habitat selection to data collected from the low-density population in the same area in 2009. Fox home range size displayed negative density dependence, as the mean home range size was 83% smaller at high densities than at low densities. Home range overlap was very low and not density-dependent. Habitat selection was density-dependent, with foxes at high densities displaying less selection overall than foxes at low densities. Vegetation type was the leading predictor for habitat selection at high- and low-densities, with foxes selecting for shrubland and against barren land regardless of fox population density. This study suggests that these generalist omnivores become more likely to use habitat in proportion to its availability at high population densities due to constraints from intraspecific competition and preservation of territoriality. Results of this study also highlight the importance of maintaining quality habitat across the entire island, as the foxes are constrained to small home ranges and forced to use all spaces, including those with less suitable habitats