1. Motorized Longboard Group 39 Daniel Moon Kevin Lee Leon Ko TA: Mustafa Mukadam 1

2. Agenda 1.Introduction 2.Review Original Design 3.Requirements and Verifications 4.Project Build and Functional Tests 5.Successes, Challenges, and Failed Verifications 6.Other Tests 7.Recommendations for Future Work 8.Acknowledgements, Questions, and Comments 2

3. Introduction Alternative, environmentally-friendly mode of transportation over short distances. Project aims to provide a commercially viable motorized longboard. Longboard both friendly to novice users and improves user experience for advanced riders Source: www.loadedboards.com Source: www.elasticpanda.wordpress.com 3

4. Features Hand-held remote controller Kill switch as safety net Assisted turning Speeds up to 15mph 4

5. Top Level Block Diagram 5

6. Specific Level Block Diagram Single Motor Motor Controller 9V Battery 6

7. Original Design Incorporate regenerative braking – Low returns Dual wheel assisted turning – Cost and inefficiency Implementation of acceleration – Improved conceptuality 7

8. Hardware Overview Microcontroller – Arduino Uno Motor – Great Planes Rimfire Outrunner Motor 1.60 Motor Controller – Hobbywing 70A Platinum HV Motor ESC Receiver and Transmitter – Xbee Module 802.15.4 1MW with Wire Antenna 8

9. Hardware Overview Potentiometer – 2-Axis Joystick Battery – 38.4 V LiFePo4 Battery Flex Sensor – Flex Sensor 4.5” by Sparkfun Infrared Sensor – Sharp Infrared Proximity Sensor Short Range 9

10. 38.4 V Battery Pack Outputs 38.4 V +/- 20% – Multimeter consistently measured 39-42 V Operating range of 4-8 miles – Test run of 4 miles (distance determined using Google Maps) achieved without battery failing 10

11. Kill Switch Ensure flex sensor can read flex of the longboard – Multimeter showed increase of resistance once rider stepped on board Ensure board does not activate motor with no rider – PWM output shown on oscilloscope to be 1 ms (0 mph) with no rider 11

12. Kill Switch 12

13. Motor Ensure communication between motor and motor controller – Motor was run with hardcoded PWM and rotation was achieved Must provide enough torque to propel rider and longboard at least 13 miles per hour – Rider was able to cover 100 yards in less than 15 seconds, signifying speed above 13 mph 13

14. Turn Assistance Making a turn results in IR output – IR sensor was tested independently with Arduino and multimeter, and a range of 0.65 V – 1.1 V seen Change in IR output results in change of PWM – IR sensor tested with Arduino and PWM monitored, and PWM change seen when turning (minimum of 0.985 x PWM for left turns, maximum of 1.01 x PWM for right turns) 14

15. Turn Assistance 15 When left turn is detected, PWM will decrease by a factor based on the sharpness of the turn. (min 1%) When right turn is detected, PWM will increase by a factor based on the sharpness of the turn. (max 1%)

16. Remote Controller User is able to hold the controller in one hand Controller components – Potentiometer, Battery, Button, On/Off switch and XBee Joystick potentiometer – analog signal – Potentiometer outputs 0 - 3.3V to XBee Brake button – digital signal – Button outputs 3.3 V to XBee when pressed Registered Signal – Arduino Terminal printed correct signals

17. Remote Battery Outputs 12 V +/- 5% – Multimeter consistently measured ~12.3 V Provides adequate power to remote components – 5 V and 3.3 V regulator used to power XBee adapter and potentiometer respectively Battery lifetime – Battery provided a lifetime of 15 hours

18. Transceiver Xbee Module 802.15.4 1MW with Wire Antenna Wireless communication Communicates properly to distance of 75 ft – Power Supply 5V regulator to XBee adapter – 3.3 V to XBee – Instantaneous communication Data is sent at 30 Hz

19. Micro Controller Arduino Uno Power Supply – 9V are supplied to the Arduino – Shield supplies 3.3 V to XBee Processes the signals from sensors and XBee – Analog - kill switch, IR sensor – Digital - braking – PWM - acceleration Outputs the correct signal to the motor controller – Thresholds were calibrated to minimize mistakes – Code printed correct outputs to Arduino terminal

20. Arduino Uno 20

21. Project Build 21

22. Functional Test 22

23. Successes Board does not move when there is no rider – Delay of ~1 second Increases/decreases PWM when joystick is tilted – Constant speed when joystick is in neutral position Board decelerates when brake button is held – Decreases PWM at a greater rate than joystick IR sensor detects turns – increases/decreases PWM by calculated ratio when turn is recognized

24. Challenges Compatibility between modules – PWM output of XBee requires low-pass filter before going to analog input of Arduino – Conversion of analog input to throttle signal compatible with motor controller Slip prevention – Added duct tape to wheel driven by motor PWM Calibration – Level of acceleration/deceleration – Speed Difference with/without Load – Changes according to tilt of board Low-Pass Filter

25. Challenges Assisted turning implementation – Flat change versus ratio Limited turning radius IR sensor on different surfaces Brake time on different surfaces Influence of topography 25

26. Failed Verifications Regenerative Braking – Low returns ~5% Reverse function – Brushless DC Motor – High Power 3-Phase H-bridge – Power MOSFETS, proper heatsinks

27. Initial H-bridge Design 27

28. Other Tests PWM Calibration – Must make sure longboard accelerates at speed desired by primary rider Active Drive Calibration – PWM increase or decrease must be proportional to turn seen, and only in the ranges desired ranges Flex Sensor Calibration – Kill switch must not activate if a small “no-rider” state is detected 28

29. Future Recommendations Reverse Function Smoother acceleration Switches and Low battery detection Lighter and more compact implementation of board Efficient regenerative braking Dual wheel drive Ergonomic Controller 29

30. Acknowledgements A big thank you to: – Board Members of the Student Leung Venture Fund – Kyle Chin and Loaded Longboard – Scott and Dave from the ECE Machine Shop – Dan from the ECE Parts Shop – Professor Carney and our TA Mustafa Mukadam – Everyone who is in attendance at our presentation 30

31. Questions/Comments 31