Senior Design Project Mid-Course Design Review Wireless Home Audio Advisor: Professor Yngvesson, K Sigfrid Group members: Wan Ng (Hardware Protel) Eric Lajoie (Networking) Anish Shah (Software Client) Huy Nguyen (Software Server) Leonard Saint-Cyr (Hardware Calculations)

Overview

Background RTES (Real-Time Embedded System) Wireless Digital UDP/IP (User Datagram Protocol/Internet Protocol) Communication connection

Challenging Choice Why did we chose the project? Interesting Wave of the future Window of Opportunity Major Challenges? Wireless programming Signal processing Abstract TINI wasn’t a good decision

802.11b (Wi-Fi) Speed ~11Mbps Distance ~300ft DSSS Direct Sequence Spread Spectrum Stream of zeros and ones Modulating with chipping sequence Barker code 11 bits sequence of zeros and ones Mathematical properties for ideal modulating radio wave Stream data is XOR’d with Barker code to create chip Each bit is encoded by 11 bit Barker code and each group of 11 chips encodes one bit of data

UDP with Ad-Hoc Fastest and most simple way of transmitting data No interference in the stream of data Provides the way to meet real-time Better for multiple programs running on a single machine Peer-to-peer connection

Server and Client Connection Server Opening a port Make a connection Get port Get IP Address *Send playlist *Send MP3 file Client Trying to make a connection Connect to port Send IP Address Connection made *Request playlist *Request MP3 file *next semester

C code Programs Create socket, for communication socket(AF_INET, SOCK_DGRAM, 0) Initialize own IP address and port addr.sin_port = htons(12345) addr.sin_addr.s_addr = INADDR_ANY

Hardware ER22 kit Printed Circuit Board (PCB) Content: STA013 MPEG 2.5 Layer III Audio Decoder CS4334 D/A Converter for Audio

ER22 Wireless Kit

Microchip ICD 2 debugger PCWH C compiler MPLAB IDE- Convert C code to assembly language MPLAB-ICD Header

MPEG Audio Layer III (MP3) MP3 files Compress a CD-quality song by a factor Still maintain the good sound quality Sample rate 32kHz, 44.1kHz or 48kHz Bit rate from 32kbits/s up to 448kbits/s

MPEG 2.5 Layer III Audio Decoder Specifications: Decodes Layer III Stereo channels, dual channel, single channel MHz external input clock I 2 C Control Bus (Serial Input Interface) I 2 S (Serial Output Interface) Bit rate and Sample rate

D/A Converter for Audio Specifications: Serial Input Interface Complete Stereo DAC system: Interpolation Over sampling Modes Base Rate Mode (2KHz-50KHz) High Rate Mode (up to 100KHz) Bandwidth and Sample Frequency Right/Left Audio Output

Protel DXP- Circuit Design

Circuit Design Cont.

Budget Items ER22 MP3 Decoder chips DAC chips PIC18 chips ICD2 Programmer CCS PCWH Books & Supplies Cost/Unit Budget – ($290x1) Free Samples – ($12x6) Free Samples – ($5x3) Free Samples – ($10x6) Dept. Cost – ($188x1) Dept. Cost – ($425x1) Personal Cost – ($210x1)

Problems and Solutions Problems TINI Bandwidth Cost Solutions ER22 (I 2 C) Linux Bases Server CLI w/ Server Code 40MHz PIC18 Family

Conclusion Software Connection (Server/Client) Send and Receive IP Packets (PING) Initialize chips over I 2 C Control the data flow to the decoder w/ buffer Custom UDP Protocol WHAMP3 Web (SSID,Channel,WEP) Hardware Research chips Compatibility Decision on chipsets Getting parts (half) Schematic Design PCB layout Final design