eNABLE Hand Test Rig P 16061 David Schwartz

e-NABLE Hand Test Rig P 16061 David Schwartz, Tia Parks, Shannon Barry, Samantha Mason, Charles Rumfola

Agenda • Background o Team o Stakeholders o Project Background o Problem Statement o House of Quality • Functional Decomposition • Concept Development • Morphological Chart • Pugh Charts • Top Options • Systems Architecture • Feasibility o Cost o Electronic o Force o Rebuildable • Designs and Flow Charts • Major Issues • Next Phase

Team

Stakeholders • e-NABLE Global community of volunteers that collaborate to design and assembly 3 D printed prosthetic hands and arms for children in need • Jon Schull Founder of e-NABLE • Skip Meetze Designer of e-NABLE prosthetics

• Previously worked on by David Schwartz as an Independent Study • Input force to make the hand grip • Output force determined when fingers begin to move when pulled • Data manually collected • Designed for only one hand design and size Input Force Project Background Output Force

Problem Statement • • Current State o David Schwartz developed a prototype for measuring grip strength. It functions, but lacks the amenities desired for the final design. Desired State o A functioning prototype that can be used to test different types of e-NABLE devices. o Device should be able to be replicated because e-NABLE is a global and open source community. Project Goals o Analyze the current accepted methods of testing grip strength. o The apparatus must be: § Easy to Use § Portable § Cost Effective § Repeatable Constraints o Can’t disassemble the hand or break the hand in the process of measuring grip strength. o Cost of end product should cost under $200 to produce.

House of Quality

Functional Decomposition

Concept Development - Mount Hand Screw/Bolt on Mold Umbrella Mechanism Clamp/Adjustable Wrench Nesting Cylinders Collapsable Shape Mechanism Modular Strap

Concept Development Actuate Wrist: Motor/Servo Manually Timer Mechanism Sense Force: Springs Dynamometer Sensors Strain Gauge Scale

Morphological Chart

Pugh Chart vs Alpha

Pugh Chart vs Automated 1

Top Options Automated 1 Automated 2

Systems Architecture

Designs and Flow Charts This is the system flow chart for both Automated 1 and 2

Cost Feasibility Assumptions: -Everything bought will work for prototype and won’t break -Don’t need highly accurate data collection (Cost Effective) Analysis: Estimated costs are derived from the required parts for the concept designs of Automated 1 and Automated 2 Automated 1 Material Clamp Servo and Encoder Force Sensors Arduino Uno Total MIS allowance (wires, bread boards, base, etc) Material Cost $20 $100 $35 (for 5) $25 $170 Clamp $20 Servo $30 Strain gauge (Includes sensor and "bars") $30 Microcontroller Processor Total $30 Cost MIS allowance (wires, bread boards, base, etc) $7 $70 $157 $43

Electronic Feasibility High level Understanding of Electronics • Microprocessor- Processes Data • Microcontroller- Control Motor • Arduino- Controls motor and processes data Assumptions: -All controllers will be compatible with our other electronics -Users will have access to a computer with Excel or will be able to download and open source program Analysis: -Based on research and analysis we have found that Arduino is compatible with Excel

Force Feasibility What is an appropriate force range for the e-NABLE fingers so we can ‘size’ our sensors/dynamometer? Assumptions: -The e-NABLE finger strength won’t surpass that of an average hand -The force should be measured to the ounce -Size of hand will have a negligible effect on force, since e-NABLE pediatric hands are relatively the same size as adult hands Analysis: Tester e-NABLE Hand Max allowable force Dynamometer Broke at 10 lb 200 lb Schwartz Independent Study Maxed out at 9 lb 25 lb Strain Gauge - 72 -180 lb (depending on the strain gauge) Force Sensors - 22 lb Conclusion: Tester doesn’t need to exceed 20 lbs of force

Rebuildable Feasibility Assumptions: -Under $200 -Other engineers who will build this will have • Basic programming knowledge • Basic construction knowledge and tools Analysis: -Budget goals are met for both Automated 1 and 2 -Making prototype -Using easily obtainable items (ex. Walmart, Amazon) -Set-Up/Construction instructions for future users

Major Issues • We don't have an Electrical Engineero This is becoming a problem because our group lacks some of the basic understandings of electronics, and one of our customer requirements is to be fully automated • Printer availability

Next Phase • • Sub-systems design Research Arduino capabilities further 3 D Print Hands - Raptor Reloaded Consider different types of motors (Servo versus Stepper)