1. ABISS: A Bluetooth Intelligent Sound System Andrew Burks Andy Heck Stephen Leotis Ben Wallingford PDR Presentation October 29, 2009 1

2. Project Overview Stream audio wirelessly via Bluetooth to the nearest receiver Provides wireless audio solution that moves with you Early adopters: tech-savvy gadget lovers Sold in sets of two for $128 2 Stephen Leotis

3. Design Objectives Monitor continuously all nearby Bluetooth receivers’ signal strength Switch audio stream to the Bluetooth receiver with highest signal strength Maintain compatibility with all Bluetooth devices Stephen Leotis3

4. System Diagram 4 Stephen Leotis Continuously monitor all Bluetooth receivers in range Stream audio to nearest receiver

5. Design Approach Bluetooth Receiver – Accepts signal via Bluetooth connection – Converts audio stream to analog signal – Outputs analog signal via TRS jack Proximity Awareness Software – Detects multiple receivers – Pairs with closest receiver 5Ben Wallingford

6. Hardware Design Receive Bluetooth signal from audio source Transmit analog audio to speakers Ben Wallingford6 WT32 Bluetooth Module LM4808 Headphone Amplifier Circuit Audio Out 3.5mm TRS 12V DC Bluetooth Signal

7. Breadboard Prototype 7 Ben Wallingford WT-32 Bluetooth ModuleLM4808 Audio Amplifier Power Regulator1/8” TRS Jack

8. Software Design Find and monitor all Bluetooth receivers in range Stream audio automatically to nearest Bluetooth receiver Run as background process Implemented initially on Mac OS X Andrew Burks8

9. Project Demonstration Demonstrate in the Klaus Building Use two receivers and two speaker systems Begin playing music and move between rooms Confirm proper functionality of audio streaming to the nearest ABISS receiver 9Andrew Burks

10. Project Demonstration 10Andrew Burks

11. Problems and Resolutions Programming Bluetooth module – Built RS232 serial programmer circuit – Initialized Bluetooth module settings to A2DP audio sink Rectifying audio quality – Built LM4808 headphone amplifier circuit – Removed noise and increased audio quality and volume 11Andy Heck

12. Current Status Hardware – Working prototype of Bluetooth receiver on breadboard. – Designing PCB for Bluetooth receiver. Software – Detects and displays the signal strength of all nearby Bluetooth capable devices. – Implementing audio switching functionality. Andy Heck12

13. 13