High Capacity Audible Wheelchair Scale NIH Design Competition Sponsored by: .

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High Capacity Audible Wheelchair ScaleNIH
Design CompetitionSponsored by
.

• BMEN 442 Team 4
• James Ball
• Kindall Carleton
• Alicia Jones
• Curtis Provost

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Overview

• Problem Statement
• Background Research and Patents
• Design Requirements and Specifications
• Scope and Limitations
• Manufacturing Process
• Improvements on Market Products
• Schematics
• Safety Considerations
• Testing
• Budget
• Timeline
• Final Discussion

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Problem Statement

• Goal
• Meet NIH Specifications Requirements
• Wheelchair Accessible
• Audible Output
• High Weight Capacity
• Tested for Accuracy
• Meet ADA Standards
• Meet Time Requirements
• Cost less than 2,000

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Background Research and Patents

• Food and Drug Administration (FDA)
• Class I physical medical device
• Americans with Disabilities Act (ADA)
• Ramp angle
• Display height
• Patent Search
• 6,268,572 portable wheelchair scale adaptor
• D489,279 wheelchair scale apparatus
• 5,994,649 portable weighing device for mobility
  disabled users

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Design Requirements

• Requirements
• Convenient for in home use
• Meets the needs of 8 potential clients
• Clientele
• Bruceleg paralysis, uses wheelchair
• Joanfragile, weak
• Maryuses walker, poor eyesight
• Lloydpoor eyesight, weighs 400lbs.
• Sophialimited right arm function, uses cane
• Davelimited right leg use, walks with cane
• Wandadeaf, weighs 80 lbs.
• Bobblind

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Design Specifications

• Reliable to nearest ½ lb.
• Wheelchair accessible
• Accessible for standing and sitting users
• Produces weight in 30 sec. or less
• Alternative output formats
• Pounds and kilograms
• Audible output

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Scope and Limitations

• 2000 budget
• Two semester time limit
• Weight range of 80lb.-400lb. including weight of
  wheelchair
• Accessible for standard, non-motorized wheelchairs

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Manufacturing Process

• Phase I- Scale Expansion
• Disassembled Scale
• Made wiring diagram
• Extended Wires
• Phase II- Frame Construction
• Finalize Dimensions
• Aluminum Acquisition
• Consultation with welders
• Initial assembly and corrections

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Manufacturing Process

• Phase III- Integration of Scale into Frame
• Load cell attachment to platform
• Ramp and castor attachment
• Display pivot modification and attachment
• Wire installation
• Troubleshooting
• Display and battery attachment

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Improvements on Market Products

• Audible with on/off switch
• Aluminum
• Self-contained
• ADA ramp
• Digital display
• Reduced weight of product
• Accessible for non-wheelchair users

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3-D Assembly Drawing
All dimensions in inches
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3-D Exploded Drawing
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Safety Considerations

• Wheelchair falling off ramp
• Wheelchair falling off the side of the platform
• Electric shock
• Sharp corners
• Slipping hazard
• Low severity and probability for all hazards
• Risk determined to be acceptable

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Risk Analysis
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Testing and Evaluation

• Accuracy against Calibrated Scale

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Testing and Evaluation

• Less than 1 Error

• Percent Mean Squared Error 0.197

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Testing and Evaluation
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Budget
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Timeline
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Final Discussion

• Achievements
• Fully functioning scale
• Testing results support accuracy goals
• Meets all requirements and specifications stated
  by NIH competition
• Potential Improvements
• Lighter base materials, e.g. glass-filled nylons
• Piezoelectric cells
• Memory tags
• Wireless Display
• Aesthetics

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Questions?