Engineering Design Workshop

Quality Design Projectsfor Engineering Fairs

Sponsored by Santa Clara Valley Science and Engineering Fair Association

for students

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SCIENCE & ENGINEERING

Scientific ProcessWhy? Knowledge

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SCIENCE & ENGINEERING

Scientific ProcessWhy? Knowledge

Engineering

Design

Process

PrototypeNeed

SpecificationScience/Technology

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Engineering Design Process

1. Define a need

2. Establish criteria and constraints

3. Research, evaluate alternatives, test plan

4. Construct a prototype

5. Test against established criteria

6. Failure analysis, tweak, and re-test

7. Final documentation

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Step #1 (Beginning) & #7 (End) Generate a Project Book

• Project data bookA complete record

All key decisions

Good drawings

Test plans

Results

Conclusions

Things learned

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Step #1: DEFINE A NEED

• Have a need, a customer for the project

• Often stated as bigger, cheaper, faster, lighter

• Engineering Goal template: The design and construction of a (engineering project) for (user) to do (some function).

• Project MUST have technical content

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The design and construction of a (project) for (user) to (function).

Project: solar powered scooter User: childrenFunction: zip around the block

Technical Content:

solar energy, energy storage, motor torque,

mechanical gear ratios, electronics

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The design and construction of a (project) for (user) to (function).

Project: wireless ear podsUser: music or radio listeners Function: avoid tangled wires

Technical Content: Analog electronics, wireless

communications

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The design and construction of a (project) for (user) to (function).

Project: kitchen shelving that lowers itselfUser: short, weak, or disabled personsFunction: easily reach items stored high

Technical Content:

Motor torque, structural design

ENGINEERING GOAL STATEMENT EXERCISE

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Step #2: Criteria & Constraints “Design criteria are requirements you specify for your design that will be used to make decisions about how to build the product”

Size

Appearance

Physical Features

Performance

Use Environment

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Some Design Constraints

• Cost

• Time

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Criteria & Constraints for Solar Powered Scooter

1. Transport up to 35 kg rider

2. Speed of at least 8 kph on level surfaces

3. Travels through 10 meters of shade

4. Material cost

5. Testing completed by Feb 28

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Criteria & Constraints for Wireless Earpods

1. Transmits 10 meter radius

2. Receiver weighs < 75 grams

3. No dropouts, ‘good fidelity’

4. Material cost

5. Testing completed by Feb 28

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Criteria & Constraints for Lowering Shelf

1. All shelves lower 45 cm

2. Safely move 16 kg up and down

3. Shelves will tilt < 10 degrees

4. Material cost

5. Testing completed by Feb 28

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Step #3: List Alternatives

• Research reveals what has been done• Likely to find good alternatives for

cheapest, fastest, or lightest• Select best alternatives that meet the

design criteria and constraints• Create a test plan based on the design

criteria from Step #2

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Web Researched Alternatives

Lowering shelves

Electrically powered scooters

Wireless earphones

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Solar Powered Scooter Test Plan

1. Transport up to 35 kg rider

Test Plan: Transport a 35kg load

2. Speed of at least 8 kph on level surfaces

Test Plan: 100m distance should take less than 45 seconds

3.Travels through 10 meters of shade

Test Plan: Charge up battery. With 35kg rider, ride through 10m of shade

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Wireless Earpod Test Plan1. Transmits 10 meter radius

Test Plan: Walk receiver in a 10m radius around transmitter

2.Receiver weighs < 75 gramsTest Plan: Weigh completed assembly

3.No dropouts, ‘good fidelity’

Test Plan: Survey student peers, likely customers

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Lowering Shelf Test Plan

1. All shelves lower 45 cm

Test Plan: Design motor to travel 45 cm

2.Safely move 16 kg up and down

Test Plan: Select motor to lift 16 kg

3.Shelves will tilt < 10 degrees

Test Plan: Design in leveling guides and careful construction techniques

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Step #4: Construct Prototype

• Prototype is implementation of chosen design alternative

• It is a proof of design, production and suitability

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Project Construction

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Step #5: Test it Well

• Execute the developed Test Plan

• Learn beyond minimum requirements! Characterize the limits of your project.

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Solar Powered Scooter Testing1. Transport 35 kg rider. Exceeds Test

Plan: Maximum mass transported2. Speed. Exceeds Test Plan: Measure

and plot speed vs. rider mass. 3. Travels through shade. Exceeds Test

Plan: Measure and plot distance in shade travel vs. rider mass.

• Extra Knowledge: solar energy, storing energy, electric motor torque, gears

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Wireless Earpod Testing

1. Transmits 10 meter. Exceeds Test Plan:Measure maximum transmission distance.

2. Receiver weight. Exceeds Test Plan: Know the weight of each component and alternatives.

3. No dropouts, ‘good fidelity.’ Exceeds Test Plan:

Higher number of surveys.

•Extra Knowledge: capacitors, inductors, antenna, ordering free samples, soldering

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Lowering Shelf Testing

1. Moves 45 cm. Exceeds Test Plan: Measure elapsed time

2. Move 16 kg. Exceeds Test Plan: Measure and plot mass vs. elapsed time

3. Tilt. Exceeds Test Plan: Measure and plot degree tilt vs. location of mass.

•Extra Knowledge: motor torque

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Step #6: Failure Analysis and Tweak/Redesign Iterations

• Evaluate the test results. Do they satisfy design criteria?

• If not, can you tweak the process as opposed to a complete redesign?

• This is the longest step….

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Failure Analysis and Tweak/Redesign Examples

• Solar scooter: Cannot move 35kg ….

• Add more solar cells, bigger motor, higher gear ratio, reduce scooter weight

• Wireless earpods: Range only 4m ….

• Increase transmitter voltage

• Lowering shelf: Shelf tilt up to 15°….

• Add stabilizing guides

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Step #7: Complete the Project Book (Started at project definition)

• Project data bookA complete record

All key decisions

Good drawings

Test plans

Results

Conclusions

Things learned

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Draw a Good Picture

• Drawings for project notebook, application, display

• Photos, sketches, CAD 2-D or 3-D

• Show assembly, components, materials

Summary

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Design Features

1. Meets a need, has a “customer”

2. Design criteria and constraints

3. Evaluate alternatives and generate test plan

4. Build prototype

5. Test/evaluate against test plans

6. Analyze, “tweak” (), redesign (), retest

7. Project book: record, analyses, decisions, specs

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Best of Luck

Engineering is exciting!

Use creative problem solving!

Ignite your passion!