Team Members

1

• Team Members
• Brant Kochsiek BWIG
• Steve Pauls Team Leader
• Tim Rand Communicator
• Brian Schwartz BSAC

2

• Client
• David Beebe, Ph. D
• Biomedical Engineering
• Advisor
• Justin Williams, Ph. D
• Biomedical Engineering

3
Abstract

• Many running injuries are caused by continued
  use of improper or worn running shoes. The
  increase in incidence of injury can be directly
  correlated to the degradation of the materials
  within the shoe sole. Our team has designed a
  device which integrates two Flexi-Force sensors
  into shoe soles in order to measure the force
  that they dissipate. The ratio of the two force
  measurements is directly correlated to the
  elasticity of a shoe sole. An analog to digital
  converter along with a microcontroller is used to
  calculate the ratio of the two force
  measurements. Based on the ratio of force
  measurements the microcontroller can be used to
  drive a tricolor LED. Current testing using an
  analog version of the circuit is being done to
  further prove the worth of the design. Testing
  will begin soon with the digital version of the
  circuit.

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Problem Motivation

• Running shoes last 300-500 miles
• Worn shoes do not always appear worn
• Risk of injury increases with worn shoes

350 miles of running wear
Less than 50 miles of running wear
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Client Requirements

• Design a device that
• Measures shoe sole elasticity
• Fits ergonomically into the shoe sole
• Is lightweight and small so as to not hinder
  performance
• Is durable enough to last the life of a running
  shoe (300-500 miles)
• Has a clear indicator so the runner will know
  when the shoe is sufficiently worn

6
Review of Design

• Two Flexi-Force sensors molded centrally in heel
  of the shoe sole
• Sensors 1 and 2 are parallel in horizontal plane
• Control circuit compares differential outputs

1
2
2
7
Improved Design Schematic

• I Flexi-Force Sensors
• II A/D Converter
• III Basic 2 Microcontroller
• IV Tri-Color LED

8
New Design Advantages

• Smaller overall size of device
• 3 op-amp circuits from previous design are
  eliminated
• Microcontroller offers memory function
• Easier to Manufacture
• Only small increase in cost

9
Semester Testing

• 2 different methods
• Test 3 different pairs of shoes on different
  runners throughout shoes life
• Test 3 pairs of shoes of same type with one
  runner

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Testing Method I

• Three different runners
• Run on shoes for full useful shoe life
• Device is inserted into shoes every 50 miles and
  tested
• With runner
• With mechanical testing machines
• Looking for circuit output vs. wear of shoes

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Advantages of Method I

• Allows testing of device in the way it will
  actually work
• Looks at individual pair of shoes
• Allows for testing of device in larger variety of
  shoes
• Nike
• Adidas

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Results from Method I (Right Shoe)
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Results from Method I (Left Shoe)
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Timeline for Individual Runner Using 3 Different
Pairs of Shoes

• (Estimated at 35 miles run per week)
• Weeks
• 0 2 4
  6 8 10
  12 14 16
• Miles Run
• 0------50------100------150------200------250-----
  -300------350------400------450-----500-----550
• ?---------------------------------------- Shoe 1
  (250 miles)
• ?------------------------------- Shoe 2 (200
  miles)
• 
  ?------------------------ Shoe 3 (150 miles)
• 
  ?---------------- Shoe 4 (100 miles)
• 
  ?----- Shoe 5 (50
  miles)
• 
  Shoe 6 (0 miles)

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Advantages of Method II

• Shoes can be cut apart during testing
• Elasticity measurements can be taken
• Can make direct comparisons between elasticity
  and shoe wear
• Allows for investigation into consistency in shoe
  manufacturing

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Results from Method II
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Final Prototype Option 1

• All components integrated into shoe
• Advantages
• More marketable
• Easier to use
• Convenient
• Disadvantages
• Cost increase per pair of shoe
• Could possibly hinder running performance

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Final Prototype Option 2

• Microcontroller/battery separate from shoe itself
  (plug in)
• Advantages
• Cost effective (No need for microcontroller for
  each shoe)
• Will not hinder running ability
• Disadvantages
• Not as convenient
• Could misplace the microcontroller rendering the
  entire device useless

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Goals for Summer 2005

• Finish all testing and analyze results
• From results estimate a reasonable threshold
  wear value
• Finish programming microcontroller
• Develop a practical method for when and how the
  user will take wear measurements
• Construct a final working prototype

20
Patent Process

• WARF filed for a provisional patent
• WARF is contacting various shoe companies
• Need to keep WARF updated with progress on
  testing and additions to design
• Develop a working prototype that is fully
  integrated into a running shoe

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Special Thanks

• Professor Justin Williams
• Professor David Beebe
• Stephanie Whitehorse
• Ivar Meyvantsson
• John Dreger