4/28/2004 Optical Tape Measure

Optical Tape MeasureMay 04-30

Team Members: Faculty Advisors: Nick Freese (EE) Dr. Aleksander Dogandzic Bruce Fu (EE) Dr. Degang Chen

Jason Thompson (CprE) Client: Eugene Zimmer (EE) Senior Design

4/28/2004 Optical Tape Measure

Presentation Outline

• Introduction• Project Activity Description• Resources and Schedules• Closing Materials

4/28/2004 Optical Tape Measure

Definitions

• Laser Driver: a device used to generate a specified pulsed output voltage to a laser

• Photodiode: semiconductor that produces current as a result of the absorption of photons

• Resolution: the speed of our designs time to digital converter

4/28/2004 Optical Tape Measure

Introductory Materials

• Problem Statement• Solution Approach• Operating Environment • Intended Users and Uses• Assumptions and Limitations• End Product

4/28/2004 Optical Tape Measure

Problem Statement

• Standard tape measures are cumbersome• Difficult to use in complex environments• Ultrasonic devices have limited capabilities

4/28/2004 Optical Tape Measure

Solution Approach

• Design an optical tape measure• Laser guided to designate the exact point of

measurement

4/28/2004 Optical Tape Measure

Environment and Users

• Operating environment considerations– Possible indoor and outdoor conditions – Physical abuse such as dropping

• Intended Users– General home owners– Construction workers– Surveyors– Architects

4/28/2004 Optical Tape Measure

Intended Uses

• General measurement• Surveying• Mining• Recreational sports• Industry

4/28/2004 Optical Tape Measure

Assumptions and Limitations

• Assumptions– The object points to be measured are stationary– The reflecting surface will be sufficiently reflective and

nearly perpendicular to the incident pulse

• Limitations– Device must measure up to 100 feet– Accuracy must be within ± 0.5%– Dimensions must not exceed 6” x 8” x 3”– Cost of the prototype must be less than $355– Device must be easily portable

4/28/2004 Optical Tape Measure

End Product

• End product description– A small, durable, lightweight optical tape

measure– A user’s manual– A maintenance manual– Test results

4/28/2004 Optical Tape Measure

Project Activities

• Accomplishments• Definition Activities• Approaches Considered• Design Overview• Implementation Activities• Testing

4/28/2004 Optical Tape Measure

Accomplishments

• Defined project specifications• Researched various technologies• Ordered necessary circuit components• Created an error model of the distance versus

timer count• Nearly completed device functionality testing• Partially completed module integration testing

4/28/2004 Optical Tape Measure

Definition Activities

• Two initial issues– Distance between two points or from the

device– Interfacing with a computer to create a model

of a room or building

4/28/2004 Optical Tape Measure

Approaches Considered

• Possibilities– Pulse Time of Flight– Modulated Beam Systems– Triangulation

4/28/2004 Optical Tape Measure

Triangulation

• Advantages– No high frequency timer or phase detector– Overall more simple– Less Expensive

• Disadvantages– Less accurate– Requires at least two lasers– Setup cumbersome and inadaptable

4/28/2004 Optical Tape Measure

Modulated Beam System

• Advantages– No high frequency timer– Fewer systematic error possibilities

• Disadvantages– A high frequency modulator is needed– Less accurate at farther distances

4/28/2004 Optical Tape Measure

Pulse Time of Flight

• Advantages– More accurate at farther distances– More information readily available– Times could be averaged over several pulses

• Disadvantages– Requires a high frequency timer– Slightly more expensive– Ambient light could be problematic

4/28/2004 Optical Tape Measure

Design Overview

Microcontroller

Timer

TransmitterDisplay

Receiver

Button

Start

Stop

Distance ≈ 3 * 108 m/s * 3.28 ft/m * time

4/28/2004 Optical Tape Measure

Implementation Activities

• Concerns– Resolution

– Rise and fall times– Laser output power and pulsing capabilities– Optimal receiver wavelength– Operating voltage

ssm

m 508/103

1524.08

4/28/2004 Optical Tape Measure

Implementation Activities

• Time to digital converter

• DEI laser driver

4/28/2004 Optical Tape Measure

Implementation Activities

• OSRAM pulsed laser diode and photodiode

• PIC microcontroller• LCD display

SPL PL85 SFH 203 PFA

4/28/2004 Optical Tape Measure

Testing Activities

• Functionality Tests– Individual modules– Module integration– Final system

• Error Analysis Tests– Accuracy– Environmental effects

4/28/2004 Optical Tape Measure

Resources and Schedules

• Personnel Effort• Other Resources• Final Project Costs• Schedules

4/28/2004 Optical Tape Measure

Personnel Effort

Team Member Hours

Freese, Nick 161

Fu, Bruce 155

Thompson, Jason 157

Zimmer, Eugene 153

Total 626

4/28/2004 Optical Tape Measure

16126%

15525% 157

25%

15324%

Freese, Nick Fu, Bruce Thompson, Jason Zimmer, Eugene

Personnel Effort

4/28/2004 Optical Tape Measure

Other Resources

$4.35

$10.73

$24.75

$169.00

$0.96

$29.00

$68.00

0 50 100 150 200

Microcontroller

LCD

Laser

Laser Driver

Photodiode

Time to Digitial

Poster

4/28/2004 Optical Tape Measure

Final Project CostsItems Cost

Poster $68.00

Laser Driver $169.00

Electronic Components $69.79

Sub Total $306.79

Labor at $10.00 per hour

Freese, Nick $1610

Fu, Bruce $1550

Thompson, Jason $1570

Zimmer, Eugene $1550

Total $6586.79

4/28/2004 Optical Tape Measure

SchedulesTasks Sept. Oct. Nov. Dec. Jan. Feb. March April May

Project Definition

Technology Research

Final Design

Implementing

Testing

Documenting & Reporting

- Planned- Actual

4/28/2004 Optical Tape Measure

Closing Materials

• Project Evaluation• Commercialization• Recommendations for Additional Work• Lessons Learned• Risk and Risk Management• Summary

4/28/2004 Optical Tape Measure

Project Evaluation

• Problem Definition (Fully Met)• Research (Fully Met)• Technology Selection (Fully Met)• End Product Design (Fully Met)• Acquire All Parts (Fully Met)• Product Implementation (Partially Met)• Testing and Revisions (Partially Met)• Documentation (Fully Met)

4/28/2004 Optical Tape Measure

Commercialization

• Capable of being fully commercialized• Production Cost: $264• Street Cost: $343• Possible market

– Forestry, Surveying, Construction• Replace inaccurate ultra sonic measuring

devices.

4/28/2004 Optical Tape Measure

Additional Work

• Commercialized version requires– Working prototype– Increased functionality – Cost optimization

4/28/2004 Optical Tape Measure

Lessons Learned

• Successful Project– Project Plan– Poster– Design/Final Report

• Things to do differently– Ordering parts– Second semester communication– Plan more time for implementation

4/28/2004 Optical Tape Measure

Lessons Learned

• Technical Knowledge Gained– Microcontroller use– LCD control– Lasers and photodiodes– Time to digital converter

• Non-Technical Knowledge Gained– Communication importance– Time management considerations

4/28/2004 Optical Tape Measure

Risk and Risk Management

• Anticipated Risks– Project Management

• Kept communication lines open• Stuck to the project plan

– Member Attitudes• Addressed problems early

– Product Risks• Chose safe laser• Cut expensive parts

4/28/2004 Optical Tape Measure

Closing Summary

• Problem– Ultrasonic Tape Measures– Inaccurate, hard to use

• Solution– Optical Tape Measure– Time of laser flight– Accurate measurement

4/28/2004 Optical Tape Measure

Questions?

Optical Tape Measure

May 04-30