Engineering Commons^™

Auto-Tuning Antenna, John Chen, Jennifer Tighe

Electrical Engineering

Radio transmitters and antennas have differing impedances at the output and feedpoint, depending on frequency. Modern antenna tuning methods involve manual or automatic resistance and reactance network adjustment to match transmitter and antenna impedance. This reduces power reflections to the transmitter, but introduces losses and prevents full transmitter power from being radiated at the antenna. This project utilizes a variable length antenna element to tune and match transmitter and antenna impedances, allowing efficient power transfer to the antenna. The antenna length varies from 0 to 30.5 inches. The method involves an RF signal with a maximum power of 2 watts …

Wireless Passive Power Transfer Using Wire Antennas, Sheng Da Zhang

Electrical Engineering

This project tests and analyzes the efficiency of directional and omnidirectional antennas in wireless power transfer for charging. The project demonstrates the steps of construction and properties of dipole, monopole, and Yagi Uda antennas. A low power high frequency DC rectifier circuit converts the received RF power from the antenna and stored it as DC voltage on a capacitor. The receiver circuit also estimates the power received by the antenna. Wireless RF power transmission proves to be inefficient for short distances. The best efficiencies of the antennas were under 50% even at 0.1meter. The near field attenuation starts at around …

Wirelessly Operated Pa Loudspeaker System For Rmax Search-And-Rescue Uav: A Preliminary Design, Travis Luke, Nolan Uchizono

Electrical Engineering

This paper discusses the approach used to implement a wireless PA loudspeaker system on a search-and-rescue RMAX UAV.

The purpose of this project is to allow the continuation of communication between search-and-rescue workers as well as potential rescuees in an environment that won't always allow it. Since rugged terrain tends to cause interference between two radio communications, there needs to be a way to bypass this problem. In addition, people in need of rescue are unlikely to be using a radio on an emergency frequency, so there needs to be a way to efficiently issue orders or evacuation notices without …

Laser Cursor, Michael Liman

Electrical Engineering

A user controls a cursor on a computer screen using a laser pointer. A camera picks up the laser pointer’s position and sends the data to the computer to move the cursor in the correct position.

Discrete Alarm Clock, Travis Moore, Collin Barth

Electrical Engineering

The standard alarm clock, as used daily by millions worldwide, has clear room for modification and improvement. This paper documents an implementation that rectifies many of these flaws. Improvements include adjustable snooze length, an IR remote for ease of use, and an RF headset for discrete alarm use or potential incorporation into a device much like a hearing aid. The processes involved in creating a digital alarm clock, as well as the obstacles met in the implementation of the enhanced design, are detailed within.

An Investigation Into Ultrasonic Communication For Near-Body Networks, Eric Joshua Escudero Jr., Gursewak Singh Rai

Electrical Engineering

The following report presents a study of body-area, free-space ultrasonic communication system. Two analog communication systems are investigated. The initial communications system setup relies upon the amplitude modulation (AM) techniques to transmit the signal. Such a system is prone to noise since the amplitude of the signal is directly affected by distance and the signal strength will deteriorate. The secondary communication system involves utilizing frequency modulation (FM). This method avoids the issue of losing information due to amplitude deterioration, but encounters delay issues. The main hardware components used in the approach outlined include ultrasonic transducers (UTs) used for both transmitting …

Digital Modulations Using The Universal Software Radio Peripheral, Daniel Keith Artis

Electrical Engineering

Software defined radios (SDRs) are versatile systems that integrate hardware and software to create a reprogrammable wireless system. Due to the versatility and hardware requirements of a SDR, they are typically expensive and not always affordable for educational institutions. GNU Radio is a free software package that allows users to do signal processing on any computer using python and C++. Using the Universal Software Radio Peripheral (USRP) board in conjunction with a standard personal computer (PC), a RF daughterboard, and the GNU Radio software, we can create a software defined radio that can transmit, receive, and process signals. Because the …

Wireless Sensor Network For Energy And Environmental Monitoring: Helping Old Buildings Go Green, Jacob Power

Electrical Engineering

Today, the rising cost of energy and social trend of “going green” has put increasing pressure on commercial property owners to improve the efficiency of their investments. There is good reason for this, too. In the State of California, office buildings represent the single largest user of energy in the commercial sector. This project consisted of the design, implementation, construction, testing, and deployment of a wireless sensor network for energy and environmental monitoring in retrofit commercial office installations. The analyzed data generated by this system can be used by building management and owners to identify areas of inefficiency within the …

Audio-To-Optical Conversion And Transmission, Jason Moritz

Electrical Engineering

The purpose of this project is to understand free-space optical transmission of signals in the application of transmitting an audio signal. An audio signal will be taken from the headphone output of a computer and used to modulate a current source driving an LED and a laser diode. The optical signal will then be transmitted through free space as well as two different focal length lenses and converted back to an audio signal to measure any attenuation or gain in the original signal. My experimental results showed that the LED was able to transmit up to 10 dB more power …

Aether, Thomas Cameron, Kristine Colton, Daren Childers

Electrical Engineering

Aether is a RC-style autonomous air vehicle that utilizes GPS positioning along with a wireless communication system to achieve a computer-controlled flight.

This report will incorporate the acquisition, design, integration, implementation and testing phases of the UAV development. Furthermore a discussion of troubleshooting as well as improvements for future projects will be included.