1. Speaker Control SYSTEM
EMBEDDED SYSTEMS FINAL PROJECT
WADE HANSEN & SORA SOGUR

2. System Diagram

3. TouchOSC iPhone App
Sends Open Sound Control (OSC) messages via to PC application
Configurable layout where input components correspond to individual OSC messages
Can send and receive messages from host inside or outside of internal Wi-Fi network - opens up many possibilities for future projects using this app

4. Processing PC Application
Open source language and IDE built for electronic arts and visual design
Similar to Java language
Uses built-in OSC library to receive OSC messages
Uses Processing Serial library functions to send data out to XBee development board
Application can also send the speaker selector commands (by clicking toggle buttons)

5. XBee RF Modems Easy to configure, low power TxRx modules
Transmits up to 300 feet indoors
Cheap! ~ $20
Uses (ZigBee wireless protocol)
In addition: 10 Digital I/O pins for sampling analog/digital signals
PC side XBee receives serial control signals via RS-232 connection and transmits to µC-side XBee.

6. Microcontroller/TxRx Board
Uses the Olimex 28-pin development board with Atmega88PA
Four output pins control relays
Two USART I/O pins connect to Xbee’s UART Data In/Out

7. Speaker Selector Module
Passive device used to switch on/off 4 separate pairs
Includes “Impedance Protection”
Four mechanical push-button switches removed, replaced by four DPDT relays.
Relay latching triggered by 4 microcontroller outputs
Indicator LEDs added to panel

8. Modified Speaker Selector Module
4 DPDT relays
Impedance Protection resistors
LEDs added to front panel

9. Speaker Switch Schematic

10. Other Potential Uses Home Automation Remote Control Tank
Security
Lighting
Power Management
Remote Control Tank
Electronic Instrument Controllers
Keyboards
Drum Machines
Sequencers
“Doggy Door Latch”
Photo Courtesy of Geeky-Gadgets.com

11. Demonstration