Flexible Custom Electric Skateboard AUTHOR: FACULTY ADVISOR: Caleb Kelsay Prof. Dale Dolan California Polytechnic State University Electrical Engineering Department Senior Project Report December 13, 2017 Table of Contents Acknowledgments........................................................................................................................... 5 Abstract ........................................................................................................................................... 6 Chapter 1: Introduction ................................................................................................................... 7 Chapter 2: Project Planning ............................................................................................................ 8 2.1 Customer Needs Assessment ................................................................................................ 8 2.2 Requirements and Specifications .......................................................................................... 8 2.3 Functional Decomposition .................................................................................................. 11 2.3.1 Level 0 Block Diagram ................................................................................................. 11 2.3.2 Level 1 Decomposition ................................................................................................. 12 2.4 Gantt Chart .......................................................................................................................... 14 2.5 Cost Estimate....................................................................................................................... 16 Chapter 3: System Design ............................................................................................................. 17 3.1 Motor Controller ................................................................................................................. 17 3.2 Battery Pack ........................................................................................................................ 18 3.2.1 Chemistry...................................................................................................................... 18 3.2.2 Energy and Power ......................................................................................................... 19 3.2.3 Battery Management System ........................................................................................ 20 3.3 DC Motor ............................................................................................................................ 20 3.4 Skateboard ........................................................................................................................... 21 3.5 Motor Mount ....................................................................................................................... 21 3.5.1 Truck Mounting Surface ............................................................................................... 22 3.5.2 Adjustable Belt Motor Mount....................................................................................... 22 3.6 Carbon Fiber Enclosures ..................................................................................................... 23 3.7 Anti-Spark Switch ............................................................................................................... 24 3.7.1 Schematic...................................................................................................................... 25 3.7.2 PCB Layout .................................................................................................................. 26 3.7.3 Component Selection .................................................................................................... 27 Chapter 4: Development and Construction ................................................................................... 29 4.1 Motor Mount ....................................................................................................................... 29 4.1.1 Waterjet and Machining ............................................................................................... 29 2 4.1.2 Second Revision ........................................................................................................... 30 4.2 Battery Pack ........................................................................................................................ 30 4.2.1 Spot Welding ................................................................................................................ 30 4.2.2 Strain Relief .................................................................................................................. 31 4.2.3 Bench Load Test ........................................................................................................... 32 4.3 Motor Controller ................................................................................................................. 33 4.3.1 BLDC Software Tool.................................................................................................... 33 4.3.2 Wireless Remote ........................................................................................................... 33 4.4 Anti-Spark Switch ............................................................................................................... 33 4.4.1 Prototype ....................................................................................................................... 34 4.4.2 Printed Circuit Board .................................................................................................... 34 4.5 Carbon Fiber Enclosures ..................................................................................................... 35 4.6 System Integration............................................................................................................... 36 Chapter 5: System Performance.................................................................................................... 37 5.1 Engineering Specification Validation ................................................................................. 37 5.2 Expense Tracking ................................................................................................................ 38 Chapter 6: Conclusion................................................................................................................... 40 6.1 Accomplishments ................................................................................................................ 40 6.2 Future Improvement Opportunities ..................................................................................... 40 6.2.1 Wireless Encryption ..................................................................................................... 40 6.2.2 Motor Mount................................................................................................................. 40 6.2.3 Battery Management System ........................................................................................ 41 6.2.4 Printed Circuit Board Integration ................................................................................. 41 Appendix A – Anti-Spark Switch Bill of Materials...................................................................... 42 Appendix B – Senior Project Design Analysis ............................................................................. 43 References ..................................................................................................................................... 49 3 List of Figures Figure 1: Level 0 System Block Diagram..................................................................................... 11 Figure 2: Level 1 System Block Diagram..................................................................................... 12 Figure 3: Gantt Chart – Winter and Spring Quarter ..................................................................... 14 Figure 4: Gantt Chart – Fall Quarter ............................................................................................. 15 Figure 5: Pack Configuration Calculations ................................................................................... 19 Figure 6: Max Speed Calculations ................................................................................................ 21 Figure 7: Truck Mounting Surface ............................................................................................... 22 Figure 8: Motor Mount Autodesk Drawings ................................................................................ 23 Figure 9: Initial Board Layout ...................................................................................................... 23 Figure 10: Vedder Anti-Spark Board v1.4 Simulation ................................................................. 24 Figure 11: New Anti-Spark Board Design Simulation ................................................................. 25 Figure 12: New Anti-Spark Board Schematic .............................................................................. 26 Figure 13: New Anti-Spark Board Layout.................................................................................... 27 Figure 14: PCB Component Calculations ..................................................................................... 28 Figure 15: Machined Motor Mount v1.0 .....................................................................................