Back AssistBack Assist

A Proximity Sensor for A Proximity Sensor for WheelchairsWheelchairs

Team 24Team 24

Stephanie TothStephanie Toth

Isabelle HarrochIsabelle Harroch

Alexander SilvermanAlexander Silverman

Kevin LynchKevin Lynch

Daniel Lofaro (Captain)Daniel Lofaro (Captain)

OutlineOutline

Problem StatementProblem Statement

Problem BackgroundProblem Background

Work Done Towards SolutionWork Done Towards Solution

Final SolutionFinal Solution

Technical Background of SolutionTechnical Background of Solution

Other Technical InformationOther Technical Information

SummarySummary

Problem StatementProblem Statement

1.5 Million Americans in wheelchairs1.5 Million Americans in wheelchairs

HazardsHazards TablesTables ChairsChairs Other PeopleOther People StairsStairs

Problem BackgroundProblem Background

AccessoriesAccessories

Power Rolls IVPower Rolls IV

CurbCurb -- ClimbingClimbing

MAidMAid

AccessoriesAccessories

JoysticksJoysticks

Light BatteriesLight Batteries

Electromagnetic BrakesElectromagnetic Brakes

Anti-Tip Solid WheelsAnti-Tip Solid Wheels

Swinging Support With Hand GripsSwinging Support With Hand Grips

Sensing DevicesSensing Devices

Power Rolls IV and Curb-ClimbingPower Rolls IV and Curb-Climbing

Source:www.indetech.comSource:www.wws.princeton.edu

MAidMAid

Source:ieeexplore.ieee.org

Design DecisionsDesign Decisions

Methods of Object DetectionMethods of Object Detection

Active vs. Passive ResponseActive vs. Passive Response

Human/Computer InterfaceHuman/Computer Interface

Final SolutionFinal Solution

Methods of Object DetectionMethods of Object Detection

Ultrasonic Sensor Infrared Sensor

Source: Original Source: Original

Active ResponseActive Response

AdvantagesAdvantages Easier on wheelchair operatorEasier on wheelchair operator More accurate than humans More accurate than humans

DisadvantagesDisadvantages Could lead to worse locationsCould lead to worse locations Prone to false reactionsProne to false reactions User’s over relianceUser’s over reliance

Passive ResponsePassive Response

AdvantagesAdvantages Eliminates active response problemsEliminates active response problems Allows the user to remain in controlAllows the user to remain in control

DisadvantagesDisadvantages Not as responsiveNot as responsive

Human/Computer InterfaceHuman/Computer Interface

Source: Original

Final SolutionFinal Solution

Ultrasonic sensors Ultrasonic sensors

Parallel sensorsParallel sensors Objects in rearObjects in rear Arm rest supportArm rest support

Downward sensorsDownward sensors Sudden dropsSudden drops Lower chair bodyLower chair body

Sensor OrientationSensor Orientation

Created with the help of Jon Bowen

Sensor and Control Box PlacementSensor and Control Box Placement

Source: www.mrmobility.com

Parallel Sensor Placement

Downward Sensor Placement

Control Box Placement

Final Solution ContinuedFinal Solution Continued

Control BoxControl Box Armrest Armrest LEDsLEDs

Parallel IndicatorsParallel Indicators 2 Yellow LEDs2 Yellow LEDs 2 Red LEDs2 Red LEDs

Downward IndicatorsDownward Indicators 1 Red LED1 Red LED

WaterproofWaterproof

Control BoxControl Box

Source: Original

Back Assist PrototypeBack Assist Prototype

Source: Original

Prototype SchematicsPrototype Schematics

Source: Original

Proximity WarningProximity Warning

Green 45-60 cmGreen 45-60 cm

Yellow 25-45 cmYellow 25-45 cm

Red 0-25cmRed 0-25cm

Proximity Warning ProgramProximity Warning Program

Source: Original

Stairs WarningStairs Warning

Green – No Stairs “Safe”Green – No Stairs “Safe”

Red – Stairs “Warning”Red – Stairs “Warning”

Stairs Warning ProgramStairs Warning Program

Source: Original

Constraints and Environmental Constraints and Environmental ImpactsImpacts

Constraints See ObjectsSee Objects CostCost FCC RegulationsFCC Regulations

Environmental DisposalDisposal

BudgetBudget

1000 Units Produced1000 Units Produced

Production Cost: $153,000Production Cost: $153,000

50% Overhead50% Overhead

Total Cost: $230,000Total Cost: $230,000

Unit Selling Price: $250Unit Selling Price: $250

Profit: $20,000 - $90,000Profit: $20,000 - $90,000

Prototype Cost: $115 + Development CostsPrototype Cost: $115 + Development Costs

All amounts are estimatesAll amounts are estimates

SummarySummary

Aware of ObjectsAware of Objects

Easy Visual OutputEasy Visual Output

Cost EffectiveCost Effective

Thank YouThank You

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