1 Lakshmi Baddam Oren Levy Marc Smith Marvin Howard Georgia Institute of Technology April 28, 2011

2 Project Overview  Workout motivation tool that will manipulate music  Motivate runner to reach target heart rate  Available to iOS mobile users  Purchased in App Store for $1.00

3 Design Goals  User-friendly GUI  Heart rate detection using Polar heart rate monitor  Music manipulation  Instantaneous performance data

4 Initial Design Overview Accelerometer Heart Rate Monitor Music Playlist User-defined Variables Music beatRunner GUI

Apple’s Bluetooth Restrictions  Pairing limited to Apple approved audio accessories  No functionality for apps to transfer or receive data and files  BTstack Alternative Bluetooth stack Pros ○ Unrestricted pairing ○ Data and file transfer Cons ○ iOS mobile device jailbreak required ○ Requires solid understanding of Bluetooth protocol 5

Modified Heart Rate Monitor Module 6 Heart Rate Monitor Interface Web ServerHeart Rate Monitor beatRunner Laptop

HRM Transmission Details  Polar T31 coded transmitter  Heart rate monitor (HRM) interface Convert ECG signal to heart rate data  HRM data Transmit to laptop via USB Laptop to webserver Webserver to iPhone  Cons System not portable Wi-Fi environment required 7

8 Workouts and Target Heart Rate (THR)  THR zone intensity Workout TypeTHR Zone Intensity Fat Burning60% - 70% Cardio70% - 80% Cross Training80% - 85% THR = (Maximum - Resting) * Intensity + Resting

9 User Input – Settings Screen Results from Calculation User defined variables used to calculate target heart rate, calories burned, and BPM Value taking from the HRM

10 App Features Cardio Fat burning Cross training  Select from three workouts  Set workout levels  Select Time Length Main screens navigation buttons Training Level

11 Accelerometer  3-axis accelerometer  Shake API class  Receive x, y, z direction values from hardware

12 Accelerometer Testing  Test screen  Put iPhone in pocket/hand  Shake motion to detect step  Increment count

Song Selection  Songs chosen based on BPM in ID3 tag  Closest BPM chosen for workout  BPM stretched ± 20% 13

Music Manipulation  Initial SOLA time stretching algorithm ○ Pro Alters tempo while preserving pitch  Actual Adjust sampling rate 14

Linear Pulse Code Modulation (LPCM)  Decompress MP3 file  Linearly sample amplitude  Play back at altered sampling rate 15

16 Cost Analysis  Budget: $400  Equipment cost Polar Wearlink+ Heart Rate Transmitter with Bluetooth – $79.95 Polar T31 Coded Transmitter - $43.99 Heart Rate Monitor Interface – $59.95  Development cost $41.27/hour wage: $56,908  125,000 downloads expected at $1.00 per download  Total profit: $68,000

17 Problems & Solutions  Bluetooth data transmission  HRM decoding  MPPlayer Class  UIAccelerometer Class  Xcode and iPhone compatibility  Functions/Parameters 17

Future Work  Portable system Transmit HRM data directly to mobile device  Calculate song BPM in app  Compatibility with other mobile devices 18

Questions/Suggestions? 19