Electrical Engineering

MEAT SMOKER

Rhianna Topp — Mon, 17 Jun 2013 10:23:01 PDT

This Senior Project consists of designing and building a meat smoker. The design of this meat smoker incorporates knowledge of control systems, programming, hardware, and materials manufacturing. This smoker is made to allow the user an easy experience of smoking food. The smoker provides the user with a programmable temperature and timer. It also has an automatic wood chip loader as deemed necessary to keep the correct amount of smoke distributed. Lastly, this smoker has an automatic application of the user’s choice of liquid to the meat. By designing a smoker with these capabilities, an untrained person desiring to smoke meat will now have the capabilities to make a desirable meat. Smoking meat has been in the past a "sport" due to its difficult nature; with this smoker design, an average person can now participate. Also, this smoker will solve the problem of time constraint people may have. A deliciously smoked piece of meat can take more than 12 hours to finish. Prior to the design of this smoker, this implies a person would have to continuously be monitoring the meat, therefore inhibiting their normal daily activities. By creating this smoker, the user only has to touch the smoker upon startup. This allows required daily activities to still be met by the user.

Energy Dashboard Tool for Cal Poly Dormitories

Katie Zombro — Mon, 17 Jun 2013 10:22:59 PDT

This project defines the needs, uses, and future projects (as well as business cases and procurement) of a University Housing dashboard tool, utilized by the Red Brick Dormitories on the Cal Poly campus. This easily accessed tool provides simple information regarding energy trending data, allowing for all student residents no matter their academic discipline, to understand their energy trends and opportunities for reduction. With the Energy Dashboard in place, Cal Poly’s red brick dormitories experienced savings ranging from 10%-20% from the 2011-2012 school year baseline, by the end of the 2012-2013 academic year. With the help of the Dashboard, competitions awarded the most “green” dorm, encouraging environmental awareness and personal responsibility. Not only has Cal Poly reduced its energy bill, but also made strides in uniting to conserve the environment.

Unipolar Pulse Width Modulation Inverter

Randy Baggao et al. — Mon, 17 Jun 2013 10:22:58 PDT

This project portrays the design and construction of a pulse width modulation (PWM) inverter. The inverter is implemented as a unipolar converter. The inverter provides a steady single-phase sinusoidal 60Hz AC voltage output from a DC input. This is a basic DC-AC power converter that is built in 3 separate phases and integrated altogether at the end. The inverter can be broken down into the control unit, firing circuit, and the H-bridge. By using the PWM method, one can control the frequency and amplitude of the output by using a reference signal. This method will also avoid using a transformer because transformers have high power losses. This project will be dedicated to EE-410 power electronics students as an experiment to observe and experience the fundamental operations of a PWM inverter circuit at Cal Poly.

Differential Transformer Protection Using the SEL 387 and SEL 587 Microprocessor Relays

Ryan Chun — Mon, 17 Jun 2013 10:22:56 PDT

The objective of this Senior Project is to use the SEL 387 current differential and overcurrent microprocessor relays to protect three-single-phase 1 KVA 120:208 transformers configured in ∆-∆, Y-Y, Y-∆, and ∆-Y connections. In the second phase of this project, is to create a functioning lab that uses the SEL 587 relay to teach basic differential transformer protection for the upcoming EE-444 students.

The protection schemes developed in both of the senior project phases require the use of differential and overcurrent protection elements by monitoring the changes of the input and output current through the transformer. When these currents fail to match, in the case of a fault, or reach a specified current set point, the relay must trip. Experimentally, these differential protection schemes will be tested by flipping the polarity of the currents going into the relay to simulate an internal fault in the transformer. Afterwards, the event report generated by the relay will be analyzed to verify the results. Because of safety limitations regarding circuit breakers, the overcurrent element will not be tested in this senior project.

The EE-444 lab will follow the same design and test procedure for the first phase of the senior project. However, the lab will use the SEL 587 in place of the SEL 387, the same 3 KVA transformers on the lab bench, and will only test the differential protection for the Y-Y transformer configuration.

Ocean Wave Generator using Electromagnetic Induction

Sutton Smiley et al. — Mon, 17 Jun 2013 10:22:54 PDT

The Visual Representation of Sound for the Hearing Impaired

Jonathan Brophy — Mon, 17 Jun 2013 10:22:53 PDT

There are many difficulties that arise when one is faced with a hearing disability. New applications of advancing technology have the potential to enable designs capable of assisting the hearing impaired with the ability to see sound. This project seeks to provide a user with a visual representation of loud noises detected using small directional microphones. The microphones determine the location of the sound above a set decibel level and a microprocessor determines the approximate location of the sound source and displays a vertical colored bar on a video image in the direction of the noise using virtual reality glasses. Two sources of input are combined in the display: the sound that is measured with the microphones, and a camera video image of what the user sees. This information is processed using an ATmega 328P micro controller and the result is displayed on the screens of the user’s virtual reality glasses.

CubeSat Launch Sequencer

Billy Beecher — Mon, 17 Jun 2013 10:22:51 PDT

I am working with the Naval Postgraduate School to develop a low cost CubeSat launch sequencer for NPSCuL that is designed to operate in low Earth orbit. The system will be capable of providing programmable delays with a minimum delay of one second to a maximum delay of five minutes. Delays must be accurate to within ± 10% or within one second, whichever is less. After the delay, the system will provide the necessary launch signal. To ensure protection from radiation, the system will feature triple redundancy and voting logic stages to ensure that the proper signal is propagated.

Off Grid Solar Powered Street Light

Justin Fang et al. — Mon, 17 Jun 2013 10:22:48 PDT

Street lights are fixtures found in every city and serve the important purpose of illuminating the streets and keeping the roads safe for pedestrians and drivers. Current street lights are powered by the grid, power which is paid for by the taxpayers and could have been used to power homes instead. With this project, our goal is to design and implement an electric power system that collects and stores solar energy, and delivers power to an LED smart street light. The resulting system would reduce street light energy costs by 100% since they would not draw any power from the grid, and would be self-contained and self-sustaining.

DC House Distribution Panel

Khanh Ho — Wed, 17 Apr 2013 10:00:33 PDT

This paper details the process in designing the distribution panel, or circuit breaker box for a DC house. The main purpose of the project is to design a distribution panel that will provide electrical power to the DC house while also providing an electrical system protection through the use of circuit breakers, or fuses. An actual hardware design for the distribution panel was built and tested. The results demonstrate the functionality of the breaker box to supply power to the DC House ensuring safe operation of the DC House.

Radio Link Analysis and Characterization of Past and Future Cal Poly CubeSats

Brian Gilbert Tubb — Fri, 14 Dec 2012 10:14:21 PST

Cal Poly's satellites design team, PolySat, has three satellites in Low Earth Orbit (LEO) and four more planned to launch within the next two years. Radio communication of past and current orbiting satellites has been an exercise in frustration, prompting significant research into the satellite-side of the radio link by several other Senior Projects and Thesis papers. However, minimal effort has been spent on evaluating why these problems were discovered only once the satellites reached orbit. This paper details the downfalls of relying heavily on link budgets and improper long range test setups, then experimentally determines the sensitivity of PolySat's primary ground station, Marconi. Results are compared to theoretical link budgets to determine incorrect parameters that need to be changed.

The ultimate goal of this testing is to pave the way for the 'New Bus' ground station. This in-development ground station uses satellite hardware to simplify ground operations and increase uplink/downlink performance and robustness. In depth sensitivity testing discovered an extremely high noise temperature of 4365K on Marconi, which will likewise limit performance on the New Bus ground station due to a similar antenna configuration. Downlink requirements will not be met until the ground station's noise floor is decreased.

Single-Phase High Efficiency Motor Testing

Marc Henry Perez — Fri, 14 Dec 2012 10:14:20 PST

A three-phase induction motor has higher efficiency than the single-phase motor counterpart. It is possible to run a three-phase motor with a single-phase source to develop a single-phase high efficiency system. The single-phase high efficiency motor, or SHE-motor, uses capacitor banks to operate at a balanced three phase induction motor using a single phase source. Unfortunately, this design has been limited, as it can only be balanced for one load configuration at a time. This provides the system to have maximum system performance. Due to this limitation in operations, it has proven to be non-ideal in commercial applications. It is seen that conventional three-phase induction motors are more practical and better suited for field applications.

Energy Harvesting Of Human Kinetic Movement

David Marusiak et al. — Fri, 14 Dec 2012 10:14:18 PST

Development of kinetic energy scavenging applications from the human body necessitates additional research to assist in designating a mounting position for a potential device. A data acquisition system adequately provides a parametric average power comparison among four locations on the body (waist, upper arm, hand, and calf) for both a male and female subject. Experimentally, the hand-held device provided the highest average power. Thus, subsequent investigation at set speeds provides further analysis of the output’s characteristically linear behavior. The physical energy-harvesting device features a plastic tube casing wrapped with the stationary coiled wire through which a neodymium magnet oscillates. While the data delivers a practical comparison for a mounting point and angle, size and power output may increase or decrease depending on variable device parameters.

Residential Grid-Tied with Battery Backup Photovoltaic System

Thomas Stobuagh — Fri, 14 Dec 2012 10:14:14 PST

When power outages occur, many homes are left without power for some time as they are dependent on the power grid. This project aims to design a residential grid tied battery backup photovoltaic system that will provide up to 7.2kW in an area that gets 5.36-5.49 kWh/m2/day [1] to support a home with an average daily usage of 28.4 kWh/day. To effectively use this system the house remains connected to the electric utility at all times, so any power needed above what the solar system can produce is simply drawn from the utility. It includes battery backup or uninterruptible power supply (UPS) capability to operate selected circuits in the residence for hours or days during a utility outage. Designing a grid tied photovoltaic system reduces dependence on the utility and provides a cost effective safety net against losing necessary power for refrigerated food storage, water facilitation, crops, and livestock.

Active Diesel Soot Measurement by Laser Opacity

Jonathan Audish et al. — Fri, 14 Dec 2012 10:14:11 PST

This project looks into understanding the concentration of soot being omitted by a diesel engine through the creation of an innovative opacity sensor. The system contains a receiver circuit implementing a photodiode, laser with wavelength of 405±10nm, and a microcontroller with analog-to-digital (A/D) converter. As the laser pulsates, the microcontroller collects and processes the data to calculate the amount of soot within the exhaust system. The opacity sensor in our tests will be used on an Isuzu 1.9 liter diesel engine. The elegant design of the system can be integrated into conventional manufacturing molding or casting processes for new exhaust systems as well as adapted to existing systems. Our system demonstrates is how an engine would be adapted. It is envisioned that new methods of emission control and testing can be developed by use of this device, including through use with an active throttle control system (passive to the driver) that would reduce visible tailpipe emissions in over-fueling scenarios.

APPLICATION OF WIRELESS POWER FOR CHARGING THE BATTERY OF A WIRELESS MOUSE

Jacob Keast et al. — Fri, 14 Dec 2012 10:14:09 PST

Electronic devices are a part of all modern homes, but restricted by available outlets and the hassle of wires. With the modern wireless mouse, this is also the case. When the battery is low the consumer has several options: it is replaced with a new battery, it can be recharged using a USB wire, or the mouse is placed on a charging dock. This project provides an alternative to these options and allows the mouse’s battery to be charged via wireless inductive coupling. The wireless power charging system that was implemented in this project was successful in its ability to utilize close proximity inductive coupling to charge the battery of a wireless mouse. A 5.0V input representing the voltage of a USB port was inverted using a push pull oscillator circuit. A sinusoidal 27.9Vpk-pk signal across the primary coil at 10.9 Mhz was achieved. A 40.2V_pk-pk sinusoidal voltage at 8.21Mhz on the receiver coil is successfully rectified to a DC voltage of 8.0V. However, the maximum efficiency achieved with a battery load is a mere 0.80%, and only 5.98% with no load. The internal resistance of the battery heavily loads the rectifier and drops V_out to 0.2V. Other reasons for such a low efficiency as well as recommendations to improve the system will be discussed in this report.

Constant Conduction Angle Bias Generation for Monolithic RF Power Amplifiers

Stephen Garber — Fri, 14 Dec 2012 10:14:05 PST

There is a need for linear, efficient monolithic power amplifiers used for the wireless transmission of signals with amplitude variations. This paper proposes a circuit that actively biases a bipolar transistor so that it operates as a Class C amplifier, with a conduction angle that is constant over a range of output powers. This results in a linear amplifier with a very low two tone intermodulation distortion. By forcing a scaled DC current vs. input magnitude curve from a Class B amplifier on to a Class C amplifier, a constant conduction angle can be maintained in the Class C amplifier. The effect of, and compensation for, a knee in the current voltage characteristics of an amplifier is simulated and analyzed. The tuning of a sweet spot in the two tone intermodulation of an amplifier is addressed. A linear constant conduction angle amplifier with a minimum two tone intermodulation distortion of -53.9 dBc and conduction angle of 137 degrees is presented.

Optical Mode Study Of Galium Nitride Based Laser Diodes

Douglas Cattarusa — Tue, 04 Dec 2012 11:06:05 PST

This paper focuses on the optical mode analysis of laser diodes to improve light emission. Under the mode analysis, we compare the optical confinement factor (OCF) percentage of the emitting light from the LDs. There are two structures which we analyze: a basic GaN waveguide structure and an InGaN waveguide structure. The second structure has additional InGaN waveguides and is analyzed under two additional design variations: the concentration of Indium and the thickness of the top waveguide layer. The results of this study indicate introducing InGaN waveguide layers correlates with lower order modes (zero and first order) and increase the OCF values. The top InGaN waveguide layer, which has a higher concentration of Indium, appears to increase the OCF. However, the increased thickness of the InGaN layer causes the lower modes’ OFC to decrease. Over all, in the best case, InGaN LD has an OCF of 1.8896%, which is about a 312% improvement compared to that of GaN LD ( OCF=0.4535%).

Water and Energy Conservation Grow System: Aquaponics and Aeroponics with a Cycle Timer

Roger Hancock — Tue, 02 Oct 2012 15:43:11 PDT

What some experts call the “blue gold”; water is a major issue in this world. There is only so much water and the reliability and cleanliness of water is what many developing countries are dealing with today. Countries around the world are facing problems with reliable water to grow enough food for their villages and homes. Is there is a way to minimize water consumption while optimizing growth in plants for food? One solution can be seen through both Aeroponics and Aquaponics. This project explores the potential of providing larger quantities of food to areas where water may be in short supply. There are four main components: the cycle timer, solar panels, the Aeroponics / Aquaponics system, and live fish.

Aeroponics is a system thru which the roots are suspended in the air and saturated with water at designated time intervals. The benefit to this style of growing is the major reduction in water consumption compared to the traditional soil farming. With Aeroponics a farmer can grow certain types of food faster and bigger while using less water.

Aquaponics, the second system, utilizes a combination of fish and plants to create a balanced system. In this arrangement fish waste (ammonia) is converted into nitrate by two types of bacteria in a series of chemical reactions. The plants then use the nitrate rich water for growth while simultaneously “cleaning” the water for the fish and removing potentially harmful nitrogen buildup. Without each other’s contribution to the system, the system would fail. The grow bed is designed to be a filter for the fish and also a growing area for the plants. This type of filter is called a bio-filter, which has living bacteria that breakdown the ammonia. This process is called the nitrogen cycle.

According to Aquaponics Earth, Aquaponic systems can conserve up to 99.75% of the water used by continuously re-circulating the system. Also that Aquaponics uses 90% less water than conventional farming techniques (Aquaponics Earth, 2012)

The cycle timer is made with 4 integrated circuits; a 555 timer, two counter chips, and a flip-flop. The cycle timer was the most logical choice for this project as it allows the user to choose the specific ON / OFF times as required by the plants in the system.

One of the goals in this project was to be able to run this system virtually anywhere. This concept included the use of solar panels. The solar panels are used to charge the battery through a charge controller with the suns energy. The DC energy is then converted into AC through an inverter. The size or number of the solar panels will depend on the size of the grow system. Also, solar can be used as a backup system if the main power goes out.

3.5 to 30 MHz Automatic Antenna Impedance Matching System

William Blodgett — Thu, 13 Sep 2012 10:09:02 PDT

Two-way communications using 3 to 30 MHz, high-frequency (HF) radio, also known as shortwave radio, provides worldwide coverage with no infrastructure required between stations. Amateur or “Ham” radio operators apply this advantage to long distance communications and to provide disaster relief communications. Optimum frequencies for long distance propagation are time-of-day variant necessitating an operating frequency range of 3 to 30 MHz. HF half wave dipole antenna length varies from 15 to 150 ft over this range. Fixed-length antenna impedance varies with frequency due to physical dimension dependent capacitance and inductance. Maximum transmitter to antenna power transfer occurs when the transmission line and antenna impedances are matched to the standard 50 Ω radio impedance. For transmitter to antenna impedance matching, antenna length can be adjusted depending on frequency. Alternately, an antenna tuner utilizing a variable inductance and capacitance matching network can compensate for the frequency dependent impedance of a fixed-length antenna. A dipole antenna designed for one frequency can function over a broader frequency range with a manually or automatically adjusted antenna tuner.

The project objective is to develop a microcontroller-based automatic tuner for a fixed length dipole antenna. In high frequency transmission lines, an antenna impedance mismatch causes power reflection back to the transmitter. This corresponds to a greater than unity voltage standing wave ratio (VSWR), the ratio of maximum to minimum transmission line voltage amplitude. A directional wattmeter provides forward and reflected power values to an Atmel ATmega32 microcontroller, which calculates VSWR and adjusts a capacitor - inductor matching network using stepper motors to reduce VSWR to less than 1.5:1 (4% reflected power relative to incident). The antenna tuner system can match loads of up to 26:1 initial VSWR within a frequency range of 3.5 MHz to 30 MHz. The system was tested using a 100 W transceiver connected to a 90 ft, 450 Ω balanced transmission line and a 120 ft dipole antenna 30 ft above ground. Commercial antenna tuners have VSWR matching capabilities from 3:1 to 100:1.

Digital Guitar Effects Unit and Amplifier

Kevin Salvador — Tue, 21 Aug 2012 17:01:32 PDT

This report outlines the design and implementation of a digital guitar effects unit and amplifier. The main portion of this project consisted of the digital equalizer and effects. Several commercial equalizers were researched in order to decide the typical frequency bands and average amount of bands total. Eventually 8 bands were selected. A range of approximately 20Hz-3kHz was chosen based on test data of guitar signals. Popular effects that were incorporated in this project include Distortion, Echo, Reverb, Chorus and Flanger. The digital processor chosen was a Texas Instruments c6713 floating point processor. Designs for the various filters were done in MatLab and implementation on the processor was done through TI’s Code Composer Studio.