1. ECE 480 Design Team 6 Lightweight Speed and Distance Sensor for Skiers and Snowboarders Michael Bekkala Michael Blair Michael Carpenter Matthew Guibord Abhinav Parvataneni Facilitator: Dr. Shanker Balasubramaniam

2. Agenda Background Background Objective Objective Design Specifications Design Specifications Potential Solutions Potential Solutions Proposed Solution Proposed Solution Conceptual flowchart and Hardware Conceptual flowchart and Hardware

3. Goal of Competitive Sports 1) Win 2) Perform better than the competition 3) Improve performance Requires tracking of statisticsRequires tracking of statistics Jump Higher Jump Higher Run Faster Run Faster Hit Harder Hit Harder

4. Bicycle Speedometer Sensor mounts to wheel and frame Sensor mounts to wheel and frame Counts time between Counts time between wheel sensor passing frame sensor Calculates wheel speed Calculates wheel speed Forward speed is Forward speed is proportional to rotation of wheel

5. Nike Plus (Nike+) Sensor placed in shoe Sensor placed in shoe Determines how long pressure is applied to the foot Determines how long pressure is applied to the foot The time that pressure is The time that pressure is applied is directly proportional to the proportional to the runner’s speed runner’s speed

6. Objective Design a speed and distance sensor for skiing and snowboarding Design a speed and distance sensor for skiing and snowboarding Current Products: Current Products: ExpensiveExpensive InaccurateInaccurate InconvenientInconvenient Objective: Objective: Greater accuracyGreater accuracy Lower costLower cost Improve functionalityImprove functionality

7. Design Specifications Safety Safety Disable display while movingDisable display while moving Functionality Functionality User definable auto shutdown timeUser definable auto shutdown time PC interface for data reviewPC interface for data review Ease of use in winter apparelEase of use in winter apparel Packaging Packaging Operate at subzero temperature (-10°F)Operate at subzero temperature (-10°F) Shock resistantShock resistant WaterproofWaterproof Weigh less than 2 lbsWeigh less than 2 lbs Cost - less than $500 Cost - less than $500

8. Potential Solutions 1) Relative Positioning 2) Inertial Navigation System (INS) 3) Global Positioning System (GPS) 4) Integration of INS and GPS

9. 1. Relative Positioning Transmitter locally placed Transmitter locally placed Sends out signal to receiverSends out signal to receiver More transmitters = Better accuracyMore transmitters = Better accuracy Receiver gets signal from Receiver gets signal fromtransmitter Calculates distance fromCalculates distance fromtransmitter Derivative of distance = SpeedDerivative of distance = Speed

10. 1. Relative Positioning Advantages: Advantages: AccurateAccurate ReliableReliable Independent of external systemsIndependent of external systems Disadvantages: Disadvantages: ComplexComplex Requires a locally placed transmitterRequires a locally placed transmitter Relative position vs. absolute positionRelative position vs. absolute position

11. 2. Inertial Navigation System 3 Accelerometers 3 Accelerometers Measure Linear AccelerationMeasure Linear Acceleration X, Y, Z DirectionsX, Y, Z Directions Integrate to get speed and distanceIntegrate to get speed and distance 3 Gyroscopes 3 Gyroscopes Measure Angular VelocityMeasure Angular Velocity Pitch, Roll, YawPitch, Roll, Yaw Integrate to get angularIntegrate to get angularposition Coordinate conversion Coordinate conversion Body Frame to ECEFBody Frame to ECEF

12. 2. Inertial Navigation System Advantages: Advantages: Very accurate for short periods of timeVery accurate for short periods of time Updates faster than GPSUpdates faster than GPS Disadvantages: Disadvantages: Requires at least 6 sensorsRequires at least 6 sensors Susceptible to bias driftsSusceptible to bias drifts Error increases over time (t^2)Error increases over time (t^2) Requires initial conditionRequires initial condition

13. 3. Global Positioning System Receives time data from satellites Receives time data from satellites Requires very accurate timingRequires very accurate timing Atomic clocks on board satellitesAtomic clocks on board satellites Triangulates position Triangulates position Uses distance fromUses distance fromsatellites Fourth satelliteFourth satellite used for error correction

14. 3. Global Positioning System Advantages: Advantages: InexpensiveInexpensive Low PowerLow Power Gives absolute positionGives absolute position Reliable over long periodsReliable over long periods of time Disadvantages: Disadvantages: Low accuracy for moving targetsLow accuracy for moving targets

15. 4. Integration of GPS and INS Proposed Design Proposed Design Combines both systems into one Combines both systems into one Takes advantage of each system Takes advantage of each system Short term accuracy of INSShort term accuracy of INS Long term reliability of GPSLong term reliability of GPS GPS keeps INS errors in check GPS keeps INS errors in check Use Kalman filter to improve accuracy of integrated system Use Kalman filter to improve accuracy of integrated system

16. 4. Integration of INS and GPS Advantages: Advantages: Most accurateMost accurate Takes advantage of each systemTakes advantage of each system Gives absolute positionGives absolute position Disadvantages: Disadvantages: More complexMore complex Requires heavy computationRequires heavy computation Requires more hardwareRequires more hardware

17. Conceptual Design

18. Hardware Components Ardupilot Sensor Board - Six Degrees of Freedom Three axis accelerometer (x,y,z) One axis gyroscope (roll) Gyro Breakout Board - LPY5150AL Dual 1500°/s Dual axis gyroscope Senses pitch and yaw

19. Hardware Components Venus GPS with SMA Connector Up to 10Hz refresh rate 28mA operating current Accuracy is <2.5m Passive Antenna -5dB Gain Quadrifilar V Omnidirectional Passive GPS Antenna