~ Audio Communication on a Wireless Network ~

Mike Pascucci

Advisor: Professor Spinelli

10/5/04

- Purpose

- Overall Goal

- Functional Diagram

- Functional Requirements

- Schedule

- Conclusion

- Questions

Portable Voice-over-IP

* Two-way audio communication between …………microcontrollers & wireless ethernet

* VoIP exists as free telephone alternative

- Advantages:

~ Free

~ Computer-to-Computer and ………………. …..Computer-to-Phone

- Disadvantage:

~ Systems using VoIP not portable

Serial-to-WiFi Ethernet

By ACKSYS

Mic to ADC

Headphone to DAC

8051 (F020) Cygnal Microcontroller

Analog voice to Digital

Digital Data to Serial Port as IP Packets

Serial to Wireless

To Internet

Digital to Analog voice

IP Packets from Serial Port to Digital Data

Wireless to Serial

From Internet…

Serial-to-Wireless sends connection request (to IP designated in code)

Connection Accepted

Voice into mic, to ADC, to serial, to IP (as packets)

Acknowledge

Digital Data to DAC, … … … … … … … … … … to speaker output

Close Connection

Connection Closed

Server Client

- Telephone Quality Audio ……~ ADC and DAC sample > 8000 bits/sec (8 Kbs) ………with 8 bits/sample

- Propagation Delay: 150-200 ms

- Ability to connect to another device

- Ability to disconnect from that device

- Transmit IP Packets with high fidelity

One 8051 Microcontroller

One Headphone / Microphone combo

Mic to ADC

Headphone to DAC

Serial-to-Serial Cable

Dedicated Serial-to-Wireless Devices

Proof of Concept for Portable VoIP

- Note: Though portable, not necessarily ………..compact – could be made so in the future

Basic Tentative Schedule:

- Stage 0 by Wednesday, November 3

- Stage 1 by Monday, December 6

- Stage 2 by Monday, January 17

- Overall Goal by Monday, February 14

Image of 8051F020 target board credit: http://www.silabs.com/products/pdf/C8051F02x-DKrev0_4.pdf

Image of Headphone/Microphone credit: http://us.st7.yimg.com/store1.yimg.com/I/directron_1812_79736366

Image of Serial-to-WiFi Ethernet credit: http://www.acksys.fr/us/produits/wl_dongle_oem.htm

References

Tackling Delay in Today’s Global Voice Networks

http://www.tmcnet.com/it/0704/Fpmcsierra.htm