This document summarizes the design and testing of a student-created prosthetic arm. It discusses the design process, materials used including PVC pipe and trimmer line, and tests of the device's dexterity, accuracy at various distances, and ability to relocate objects. Testing data shows the device is effective but accuracy declines with distance. The design is cost-effective but could be improved by reducing weight and adding insulation. The team recommends further tests for real-world use and increasing the device's mechanical advantage.

1. Factors Considered
Component Options: Hand Mechanism
Claw / Netting
Dexterity TaskObject Relocation TaskDistance Accuracy Task
Spring Clamp

2. Component Options: Mounting Apparatus
Long-Sleeve T-shirt PVC Pipe
Factors Considered
Comfort Cost Speed

3. Component Options: Mounting Apparatus
LeashLeather Figure-8 Harness
Factors Considered
Comfort Cost Complexity

4. Component Options: Cable
Latex Tubing Butcher’s Twine
Factors Considered
Comfort Cost
Trimmer Line
Strength

5. Team Members and Roles:
 George Jenkins - Captain - Senior - 2nd Year - Product Design, Report, Presentation
 Cody Rogers - Senior - 2nd Year - Product Design, Performance Challenges
 Shade Jenifer - Junior - 2nd Year - Product Design, Performance Challenges
 Christian Warren - Junior - 1st Year - Product Design, Report, Presentation
Maryland - Henry E. Lackey High School
Prosthetic Arm Team

6. The Prosthetic Arm Challenge detailed design criteria and testing
specifications for a trans-radial prosthetic device. Devices are scored based on
the distance accuracy relay, the object relocation task, the dexterity task, and
design efficiency. This report details the efforts of the second Henry E. Lackey
Prosthetic Arm Team to meet the goals of the challenge up to June 3rd, 2014. It
includes a discussion of research, material choice, and other components of
the design evolution, along with STEM influence and principles, and an analysis
of preliminary tests. This design is a cost effective, efficient, and effective trans-
radial prosthetic device. The tension created by straightening the user’s arm
and the force created by the spring of the spring clamp is enough to hold and
relocate relatively heavy objects. The device can be used to thread nuts onto
bolts and throw ping pong balls, albeit with some difficulty. Additionally, the
design is composed of highly cost-efficient materials. The design can be
improved by focusing on the hand mechanism and the direct tension
mechanism. If the direct tension method of design was maintained, possible
re-design concepts would include using simple machines or a pulley system to
enable an increase of the spring tension of the clamp but allow the force
produced by straightening the arm to remain the same. Even without these
advancements the current design remains an effective trans-radial prosthetic
device and could be effective in a real life application.
Abstract

7. Constraints
$40 Budget Trans-RadialOperates Independently of
Hand and Opposing Arm
Finger Number
Opening Distance
Weight
Multiple Users

8. Working Drawing

9. Related Physical Phenomena
Compression: 33 lbs Tension
FrictionMuscle

10. Bill of Materials
Design Process Challenge Prep Technical Report Back Board/ Presentation Prep
56 Hours 20 Hours 12 Hours 26 Hours
Time
Total Time: 114 Hours
Part Unit Dimensions Retail Price Price per Unit Quantity Used Total Cost Retail Source
PVC Pipe
Charlotte Pipe 6- in x 10 ft
Sch 40 PVC DWV Pipe
$42.48 $0.354/inch 15.5 Inches $5.49 Lowes.com
Hardwood Oak, Red 3/4" x 4" x 48" $15.75 $0.08/inch^2 18 Inches^2 $1.44 Woodcraft.com
Leash Large, 6ft $6.49 $6.49/Leash 1 Leash $6.49 Chewy.com
Trimmer
Line
Husqvarna 639 00 51-05
230 ft Titanium Force
Premium
$15.99 $0.08/foot 3 Feet $0.24 vminnovations.com
Wood
Screws
75 Pack, 1-3/4" $3.14 $0.042/screw 8 Screws $0.33 midlandhardware.com
Spring
Clamp
Jaw Opening Capacity
(Inch): 3 Overall Length
(Inch): 9
$8.36 $8.36/clamp 1 Clamp $5.85 use-enco.com
Sponge 9" x 5" $1.79 $1.79/sponge 1/2 Sponge $0.90 Amazon.com
Bolts
100 Pack, Width: 3/8",
Length: 1-1/2"
$165.50 $1.655/bolt 2 Bolts $3.31 Lowes.com
Nuts 25 Count, 3/8" $2.74 $0.1096/nut 2 Nuts $0.23 Lowes.com
Washers 50 Count, 3/8" $3.99 $0.0798/washer 2 Washers $0.16 Amazon.com
Butt
Conector
50 Count, 12-10 Gauge $7.15
$0.143/Butt
connector
1 Butt
connector
$0.14 protelecomsupply.com
Total $24.58

11. References
• Norton, K. M. (n.d.). inMotion: A Brief History of Prosthetics. Amputee Coalition - Resources for amputees, amputation, limb loss,
caregivers and healthcare providers. Retrieved March 15, 2014, from http://www.amputee-
coalition.org/inmotion/nov_dec_07/history_prost
• Burck, J., Zeher, M. J., Armiger, R., Beaty, J. D., & Laboratory, J. H. (n.d.). Developing the World’s Most Advanced Prosthetic Arm
Using Model-Based Design - MathWorks News & Notes - 2009. MathWorks - MATLAB and Simulink for Technical Computing.
Retrieved March 15, 2014, from http://www.mathworks.com/company/newsletters/news_notes/2009/jhu-model-based-
design.html
• Scott, D. (n.d.). University of Illinois Students Design $300 Prosthetic Arm | Complex. Complex | Style, Music, Sneakers,
Entertainment, Girls, Technology. Retrieved March 15, 2014, from http://www.complex.com/tech/2012/11/university-of-illinois-
students-design-300-prosthetic-arm
• Chorost, M. (n.d.). A True Bionic Limb Remains Far Out of Reach | Wired Science | Wired.com. wired.com . Retrieved March 15,
2014, from http://www.wired.com/wiredscience/2012/03
• AMO Arm pneumatic prosthetic does mind-control on the cheap. (n.d.). Engadget. Retrieved March 15, 2014, from
http://www.engadget.com/2011/04/05/amo-arm-pneumatic-prosthetic-does-mind-control-on-the-cheap/
• Nylon Dog Traffic Leash 1-inch x 2 foot Blue - Dog Leashes Nylon. (n.d.). Arcata Pet Supplies - Online pet shop for all your supply
needs. Retrieved March 15, 2014, from http://www.arcatapet.com/item.cfm?cat=794
• Magellan self-actuated prosthetic device can be operated with your smartphone | The geek's guide to awesomeness | DamnGeeky.
(n.d.). The geek's guide to awesomeness. Retrieved March 15, 2014, from
http://www.damngeeky.com/2012/08/15/4071/magellan-self-actuated-prosthetic-device-can-be-operated-with-your-
smartphone.html
• Alfred Mann Foundation » Limb Loss. (n.d.). Alfred Mann Foundation. Retrieved March 15, 2014, from http://aemf.org/our-
research/current-focus/limb-loss/spring clamp. (n.d.). plastic spring clamp for hundreds of uses. Retrieved March 15, 2014, from
http://www.alibaba.com/product-gs/341861413/plastic_spring_clamp_for_hundred

12. Testing: Data Tables
Object Relocation Testing Dexterity Challenge Testing

13. Distance Accuracy Relay Testing
0
10
20
30
40
50
60
70
80
2 meters 3.5 meters 5 meters
Successes
Distance
Arm Throws
Tennis Ball
Kick Ball
Ping Pong Ball
0
10
20
30
40
50
60
70
80
90
100
2 meters 3.5 meters 5 meters
Points
Distance
Arm Points
Tennis Ball
Kick Ball
Ping Pong Ball
0
10
20
30
40
50
60
70
80
90
100
2 meters 3.5 meters 5 meters
Successes
Distance
Control Throws
Tennis Ball
Kick Ball
Ping Pong Ball
0
20
40
60
80
100
120
140
2 meters 3.5 meters 5 meters
Points
Distance
Control Points
Tennis Ball
Kick Ball
Ping Pong Ball
Rapid Descent
Steady Decline

14. • Accuracy data indicates success with lighter objects.
• Accuracy degrades as distance grows.
• Data indicates speed and weight requirements of daily life are met.
• Device has moderate fine motor control.
Design Analysis
Strengths Weaknesses
• Design Simplicity
• Cost Efficiency
• Strength of Clamp
• Mobility
• Ease of Use
• Ease of Maintenance
• Weight of Device
• Comfort
• User Operating Strength

15. Conclusions
 Device is a cost effective, efficient, and effective trans-radial
device.
 Device performs highly in each of the tested areas.
 Device could be used in a real world application.
Recommendations
We would:
 Conduct further tests for real life application.
 Further reduce the weight of the device.
 Add insulation into interior of device and edges.
 Increase mechanical advantage of the device.
• Pulley System
• Position of the leash
Conclusions / Recommendations