Syllabus

Advisors

Dr. Aaron Hawkins, 437 CB, 2-8693, hawkins@ee.byu.edu
Dr. Stephen Schultz, 444 CB, 2-1693, schultz@ee.byu.edu
Office Hours: as posted; please respect them

Course Info

TTh, 10-10:50am, 369 CB
TTh, 9-9:50am, 250 CTB

Course Overview Work in three- or four-person teams to construct a free space optical communication system capable of transmitting and receiving data from a DVD player. The system will consist of two parts – a laser transmitter and an optical receiver. The laser transmitter will take the digital bit stream out of a DVD player, and produce matching optical pulses. The receiver will translate these optical pulses back to an electrical bit stream that can be read by an audio receiver. The system should produce high fidelity audio transmission at DVD bit rates.

Each team’s communication system must demonstrate high fidelity transmission over a range of at least 20 feet, fit inside of the provided package, and have enough dynamic range to operate between 5 and 20 feet without any adjustment to the electronics (i.e. potentiometers)

Provided components:

Two webcams
2 lasers
1 optical detector
2 AC/DC power supplies

The final system will be graded based on the completeness of the design, packaging, and documentation. The completed system will need to include a specification document and user’s manual. The setup and operation of the system during the final demonstration will be accomplished by someone external to the senior project. So make sure that your system is easy enough to use and your documentation is adequate.

There will also be a competition for the team whose system can be set up the quickest by the judge (a person chosen by the instructors who is not a member of any of the groups). The set up time will include separation distances of both 5 and 20 feet. The specifics of the competition will be determined later in the semester. The team with the fastest setup time will gain extra credit.

Grading criteria

Your base grade is based on the performance of your system. The base grade is adjusted up or down based on your milestone reports, your oral reports, and your performance in the business portion of the class.

A Range (Base Grade of A-): The judge can setup your system using the provided documentation to transmit music at both 5 feet and 20 feet.

B Range (Base Grade of B): The judge cannot get the system to work at both 5 feet and 20 feet but the group members can get it to work.

C Range (Base Grade of C): The group members cannot get the system to transmit music at 5 feet and 20 feet but can demonstrate connectivity with a function generator and oscilloscope. The frequency of the function generator needs to be at least 1 MHz.

Weighting of the milestone reports and presentations:

20%	Project Plan
20%	1st Design
25%	2nd Design Review
35%	Final Demonstration

Project plan

This milestone will be the development of system specification document and a project plan.

This milestone will NOT include a presentation.
This report will include the Functional Specification Document (FSD).
The report should provide an overview of the system with a block diagram.
It should also include a test plan. The test plan will describe how the various sections of the project will be tested.
The report must also include measurement of the various components that were provided to you. The set of measurement should include at least the following.
Voltage level of digital DVD output

Bit rate of digital DVD output
Rise and fall times of the digital DVD output
Measured laser power as a function of supplied current (with a maximum current of 30 mA)

Minimum spot size vs. distance and corresponding beam divergence
Remember that you should adjust the lens for each distance
Be sure to explain what you designate as spot size

The output current of the photodetector as a function of optical input power. You will use your laser to make this measurement.
Estimate of the amount of optical power that will be received by the photodetector at 5 feet and 20 feet and the current that will be produced by the photodetector

It should also include a description of the different roles of the various members of the group.
It should state what measurements will be made for each of the additional reports. A list of the minimum measurements that need to be included in your reports is provided at the end of this document. All of these measurements need to be included plus any additional data that you think would be useful.

1st Design Review

This milestone demonstrates that you are on track to complete the project on time. The primary completion of this milestone is a functioning transmitter and the design and simulation of the receiver.

This design review will include a presentation. <\li>
The Concept Generation and Selection Document will have already been turned in to Doug Clifford, but it should also be incorporated into this report. <\li>
Demonstrate that the digital output of the DVD player can be plugged directly into your laser driver and produce an optical signal that matches the shape of the DVD’s digital output. The laser driver needs to be built using discrete components. (You cannot buy a laser driver board.) <\li>
The report needs to contain a project schedule. <\li>
The milestone should also include a design of the receiver. You need to estimate the required gain of the receiver. <\li>

2nd Design Review

This milestone is a design review of the complete system. The complete system must include the following

This design review will also include a presentation. <\li>
A system that takes the digital DVD output, converts it into a modulated optical beam, transmits it through space, and demodulates the signal to be heard on a speaker over a distance of 20 feet <\li>
Sufficient dynamic range to operate at either 5 feet or 20 feet <\li>
A plan to fit the systems into the webcam packages. <\li>
The complete system is due early in the semester to allow you enough time to transfer your receiver and transmitter onto circuit boards. If you desire you can have a commercial board fabricated. Details on this will be discussed later in the semester. <\li>

Final Demonstration

The final demonstration will include the following.

A system that takes the digital DVD output, converts it into a modulated optical beam, transmits it through space, and demodulates the signal to be heard on a speaker over a distance of 5 feet and 20 feet <\li>
A specification document <\li>
An operating manual <\li>
This design review will also include a presentation. <\li>
The presentation will be given after the demonstration. <\li>

The final demonstration will be a judge setting up your system using your operating manual. The system will first be set up with a separation distance of 5 feet. Then the system will be set up at 20 feet. In addition to judging the system on operation, the system will also be judge based on the look of the system and the easy of set up at the two distances.

Other Information

Here is a list of some of the data that should be included in the various reports. This list is not complete but is to give you any idea of the type of information that should be included in reports.

Simulated frequency response of the transmitter <\li>
Measure frequency response of the transmitter <\li>
Simulated frequency response of the receiver <\li>
Measured frequency response of the receiver <\li>
Measured power consumption of both the transmitter and receiver <\li>
Measured minimum detectable power of the receiver <\li>
Measured power density at 5 feet and 20 feet (W/cm2) <\li>
Measured alignment sensitivity <\li>
Voltage range of the commercial receiver box. This characterization should NOT include voltages above the level produced by the DVD player. <\li>
Find any standards related digital audio transmission protocols. (i.e. what is the DVD using) <\li>
Put eye safety class on your device <\li>
Document the eye safety requirements and specifications <\li>
Distance range over which the system will transmit music (This range should be at least 5 feet – 20 feet.) <\li>