Bangarang Musical Engineering

1. Bangarang Musical Engineering University of Notre Dame Department of Aerospace and Mechanical Engineering Group Members: Roberto Ayala, Ryan Bradley, Pat Fox, Matt Medlock, Mike Tieu

2. Outline of Presentation • Project Overview and Objectives • Concept Selection • Identification of Technical Challenges and Feasibility Issues • Prototype Creation • Feasibility Assessment • Conclusions

3. Project Objectives Task: Develop an innovative musical instrument Requirements: -- Play in an automated and manual fashion -- Utilize embedded intelligence

4. Concept SelectionInitial Concepts and Design Considerations Air Guitar Concept Fan Sound Generation Key Design Considerations for Final Concept -- Enable disabled people to play a new instrument -- Generate mechanical sound

5. Concept SelectionTarget Market Identification • Initial Target Market: People suffering from motor-skill disabilities • Confirmed from meeting with physical therapist -- “Call-and-response” method of rehabilitation • Target market now includes neuro-rehabilitiation capabilities

6. Concept SelectionFinal Design Concept • Group chose to pursue a mechanically operated drum set • Features: -- Two Drums Sticks -- Two Actuators

7. Key Technical Challenges and Feasibility Issues • Drum stick actuating mechanism -- Solenoid Selection • Selection of pressure sensors • Drum stick material selection • Minimizing system response time • Generating variable volume

8. Key Technical Challenges and Feasibility IssuesSelection of Drum Stick Actuator • Five actuating options considered: -- solenoid, linear motor, rotary/servo motor, stepper motor, pneumatic systems • Merit based comparison: -- cost, estimated response time, durability, variable force control • Selected a push solenoid as the actuating mechanism

9. Key Technical Challenges and Feasibility IssuesSolenoid Selection • Investigate stick tip velocity and actuation force through two trade studies • Requirements: -- 65 dB of sound output -- Stick tip velocity of 7 ft/s • Selected a solenoid with a stroke length of 1.0 ” and 5 lbf of pushing force -- Attached a spring with constant 3.34 lb/in to recoil stick

10. Key Technical Challenges and Feasibility IssuesPressure Sensors • A trade study investigated the force exerted during finger tapping • Selected 0 to 1 lb pressure sensors

11. Key Technical Challenges and Feasibility Issues Drum Stick Material Selection • Study conducted in order to determine the drum stick tip material • Selected wood as the material -- Greatest slope

12. Key Technical Challenges and Feasibility IssuesMinimizing System Response Time • Electrical response from sensors was negligible (5 µs) • Main contributor was mechanical response -- Solenoid push -- Stick recoil

13. Key Technical Challenges and Feasibility IssuesGenerate variable volume • Desired to create three different volumes -- Pressure Sensor -- Microcontroller -- DC Solenoid • Utilized three different microcontroller pins to output variable volume commands

14. Prototype CreationCAD Modeling • CAD model created to visualize the prototype

15. Prototype CreationCritical Functions • Will prove concept feasibility in the following areas: -- Generate variable volumes greater than 65 dB -- Function both manually and autonomously -- Operates at a minimum rate of 1 beat/s • Additional goals: -- Robust design • Budget Requirements: -- Maximum $500 -- Actual Cost - $432

16. Prototype CreationManufacturing -- Striving towards a prototype with complete adjustability Frame Mount Clevis

17. Prototype CreationCompleted Prototype

18. Prototype CreationDemonstration

19. Feasibility Assessment • Prototype effectively demonstrated product feasibility • Scored 95/100 on team-developed performance requirements Prototype Strengths: -- Pressure sensor effectiveness -- Minimum mechanical complexity -- System response time -- Packaging and presentation -- Robust Prototype Weaknesses: -- Circuit assembly problems -- Extra sound from solenoid actuation and contact with mount -- Over weight limit

20. Conclusions • Product has high market potential • Group believes that product will be successful • Prototype demonstrates product feasibility Final Product Changes: -- Drum size -- Circuit design

21. Questions????

22. Questions Asked: • Question: How important was it to return the stick to its original position? • The stick had to be returned to its initial position to be able to change the volumes at which the drum played. If the drum stick did not return to its initial position, the variable force firing of the solenoid would have little to no effect on the stick tip velocity, thus making it impossible to change the volume. • Additionally, the stick had to return to its original position because otherwise, it would not create sound. If the drum stick remained in contact with the drum head, the firing of the solenoid would not generate sound. The stick would be driven through the drum head. • Question: How durable was the spring? • The spring was effective for our use. The design team feels that because of the spring constant, the durability of the spring would not be an issue. • Question: How easy would it be to add components? • Adding components would be a significant challenge that would need to be thought out. By adding more components, the weight of the design would be significantly increased, which would cause the apparatus to be difficult to move around. Additionally, to fit the design through a set of doors, one could not extend the size of the frame to include more components. This question requires much more thought, and would need to be fully investigated if pursuing the product. • Question: Have you performed a patent search? • We have not performed a patent search. We are pursuing undergraduate design competitions in an effort to get the design noticed.