ECE 480 Design Team 6 Lightweight Speed and

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

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

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

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

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

Objective n n Design a speed and distance sensor for skiing and snowboarding Current Products: • • • n Expensive Inaccurate Inconvenient Objective: • • • Greater accuracy Lower cost Improve functionality

Design Specifications n Safety • Disable display while moving n n n Functionality • • • User definable auto shutdown time PC interface for data review Ease of use in winter apparel • • Operate at subzero temperature (-10°F) Shock resistant Waterproof Weigh less than 2 lbs Packaging Cost - less than $500

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

1. Relative Positioning n Transmitter locally placed • Sends out signal to receiver • More transmitters = Better accuracy n Receiver gets signal from transmitter • Calculates distance from transmitter • Derivative of distance = Speed

1. Relative Positioning n Advantages: • Accurate • Reliable • Independent of external systems n Disadvantages: • Complex • Requires a locally placed transmitter • Relative position vs. absolute position

2. Inertial Navigation System n 3 Accelerometers • • • n 3 Gyroscopes • • • n Measure Linear Acceleration X, Y, Z Directions Integrate to get speed and distance Measure Angular Velocity Pitch, Roll, Yaw Integrate to get angular position Coordinate conversion • Body Frame to ECEF

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

3. Global Positioning System n Receives time data from satellites • Requires very accurate timing • Atomic clocks on board satellites n Triangulates position • Uses distance from satellites • Fourth satellite used for error correction

3. Global Positioning System n Advantages: • Inexpensive • Low Power • Gives absolute position • Reliable over long periods of time n Disadvantages: • Low accuracy for moving targets

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

4. Integration of INS and GPS n Advantages: • Most accurate • Takes advantage of each system • Gives absolute position n Disadvantages: • More complex • Requires heavy computation • Requires more hardware

Conceptual Design

Hardware Components Ardupilot Sensor Board - Six Degrees of Freedom • Three axis accelerometer (x, y, z) • One axis gyroscope (roll) Gyro Breakout Board - LPY 5150 AL Dual 1500°/s • Dual axis gyroscope • Senses pitch and yaw

Hardware Components Venus GPS with SMA Connector • Up to 10 Hz refresh rate • 28 m. A operating current • Accuracy is <2. 5 m Quadrifilar V Omnidirectional Passive GPS Antenna • Passive Antenna • -5 d. B Gain