ECE 477 Digital Systems Senior Design Project Spring 2007

Homework 2: Design Project Proposal Due: Friday, January 19, at NOON

Team Code Name: Sounds Good Group No. 7

Team Members (#1 is Team Leader):

#1: Joe Land Areas of Expertise: EE

#2: Ben Fogle Areas of Expertise: EE

#3: James O’Carroll Areas of Expertise: EE

#4: Elizabeth Strehlow Areas of Expertise: EE

Project Abstract:

This project is designed to digitally steer sound through a pair of stationary loudspeakers. Each loudspeaker element will have its own delay and volumes control settings to direct the sound. The modern design will also incorporate a control box with a user interface. This interface will allow the user to set up the speakers in a non-idealized room and have a clear stereo image projected towards a desired location. These loudspeakers will also be time-aligned to enhance their performance.

Design/Functionality Overview:

The idea behind this project is to create a digitally steerable loudspeaker available at the consumer level. Since the sound can be pointed in different directions, the speakers can be placed in non-ideal locations. Effectively, the sound is independent of the acoustics of the room and can be limited to only the intended users. The set of two loudspeakers and control box will be easy to use and modern in design. The current plan is to have eight steerable speakers in each loudspeaker. The loudspeaker will nearly operate at the full audible spectrum, with subwoofers built into the unit as well. The intended functions include a control box with a user interface to allow the user to adjust the settings of the loudspeakers. This interface will include a display with eight touch buttons for the user to control all setup and normal operation settings. An infrared sensor will also be incorporated into the control box so that a universal remote can be used to change the ECE 477 Digital Systems Senior Design Project Spring 2007 volume and toggle between audio inputs. In order to facilitate these requirements, the design will also incorporate a DSP interface. The DSP will be used for manipulation of volume, delay, equalization, and filtering of each of the eight speakers per enclosure.

The following includes the cost estimate information for each of the two loudspeakers: Item Part Number (if Applicable) Cost Estimate microcontroller ATmega8 $4 DSP ADSP 212625 $25 A/D and D/A CODEC AD1835AAS $10 Power Supply undecided $50 boards undecided ? 8 loudspeakers 269-566 $10 each 8 loudspeaker amplifiers TPA3001D1 $6 each Subwoofer Custom $20 Subwoofer amp 50-6273 $25 Wood for enclosure N/A $25 There is also a development kit for the DSP that was checked out to the team, so there is no cost associated with this. Therefore the total cost for each speaker is approximately $287, plus the cost of the PCBs. The costs for the control box are approximately the following: Item Part Number (if Applicable) Cost Estimate microcontroller ATmega16 $4 Universal Remote undecided $10 IR sensor undecided $10 5.5” LCD TV display undecided $50 Video chip ezVid $60 2 Touchbutton chips QT240 $19 each (evaluation kit) Op-amps TL072 $8 Cables miscellaneous $10 The total estimated cost of the project is approximately $762, plus the cost of the PCBs. The breakdown of the contribution is expected to be as follows. In addition to being the team leader, Joe is responsible for the acoustical and enclosure design and modeling, PCB design, interface design of the audio circuit design for the pre-amplifier and amplifier design. Ben is working on the DSP software design and incorporating the software for the delay, volume control, and equalizer. He is also responsible for the microcontroller, DSP, and Codec interface. James is responsible for the microcontroller design, including the design for the microcontroller ECE 477 Digital Systems Senior Design Project Spring 2007 interface and the user interface to the speaker control interface. Elizabeth is responsible for the interface hardware design, which includes hardware design and support for the microcontrollers and the DSP, the PCB design, the Codec hardware design, and the user manual.

Project-Specific Success Criteria: 1. An ability to receive/decode infrared signals 2. An ability to steer sound 3. An ability to switch between two stereo inputs 4. An ability to interface with a DSP 5. An ability to crease a user interface which controls the loudspeaker settings

Block Diagram:

Serial to Video Infrared 38kHz ATD SCI Sensor Converter ATmega16 8 8 8 Touch Buttons Touch Button I/O Controller 5.5” LCD TV

Header I/O 4

4 Control Lines +12 V / +5V

Interface Connection to Loudspeaker Board

Figure 1 - Control/User Interface ECE 477 Digital Systems Senior Design Project Spring 2007

I/O ATmega8 4 I/O 4 Control Lines +12 V / +5V Header SPI Interface Connection to Loudspeaker Board

SPI SPI Flash SPI 512k DSP ADSP-21262 I/O Shift Registers SRAM 8Mb Header SPI Audio x 8 Inputs x 2 2” Speaker SPI L Analog Switch Audio Pre-A/D CODEC Audio Post D/A 10W Class D R Analog Circuit Analog Circuit Power Amplifier AD1835A

55W Class AB 8” Subwoofer Power Amplifier Power +12V 8A Supply + 5V 2A

Figure 2 – Block Diagram of Design ECE 477 Digital Systems Senior Design Project Spring 2007

2” Loudspeaker

Array of 8 Loudspeakers

Loudspeaker Enclosure

8” Subwoofer

Front View

Figure 3 – Illustration of Loudspeaker Enclosure

Division of Labor: Design Component Homework Professional Component Homework Packaging Design and Specs James Design Constraint Analysis/Parts List Joe Circuit Schematic and Narrative Elizabeth Patent Liability Analysis Ben Printed Circuit Board Layout Joe Reliability and Safety Analysis James Software Narrative and Listing Ben Social/Political/Environmental Analysis Elizabeth