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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