ECE 477 Digital Systems Senior Design Project Spring 2007
Homework 4: Packaging Specifications and Design
Due: Friday, January 26, at NOON
Team Code Name: _Sounds Good______Group No. _7____
Team Member Completing This Homework: _James O’Carroll______
e-mail Address of Team Member: _jocarrol_____ @ purdue.edu
Evaluation:
Component/Criterion / Score / Multiplier / PointsIntroduction
/ 0 1 2 3 4 5 6 7 8 9 10 / X 1Commercial Product Packaging / 0 1 2 3 4 5 6 7 8 9 10 / X 3
Project Packaging Specifications / 0 1 2 3 4 5 6 7 8 9 10 / X 2
PCB Footprint Layout / 0 1 2 3 4 5 6 7 8 9 10 / X 2
List of References / 0 1 2 3 4 5 6 7 8 9 10 / X 1
Technical Writing Style / 0 1 2 3 4 5 6 7 8 9 10 / X 1
TOTAL
Comments:
1.0 Introduction
Digital sound projection, while based on digital signal processing (DSP) techniques that have been well established for several decades, is a technology that is only recently finding widespread application within consumer, industrial, and government markets. By combining more traditional audio design techniques with well-implemented delay algorithms, it becomes possible to produce clear sound in a digitally chosen region. A number of products with these design features in mind are replacing loudspeakers in public areas where acoustics are complicated or have undesirable features such as echoing. However, there are presently only products in the consumer market appropriate for medium to large sized areas. This project sets out to create a product appropriate in size, cost, and application for placement in a home or smaller room. An appropriate product to facilitate this concept is a set of two speaker towers with an additional control box and remote. The controlling interface, software, and display need to be capable of displaying and changing the relatively complicated settings available in such a product, and must also be either attractive or unobtrusive. Considerations such as total size, individual speaker layout, and construction materials rely primarily on the need for parts of sufficiently high quality to promote the unique sound directing features of the project, and to also create a balance between aesthetics and overall cost.
2.0 Commercial Product Packaging
Two forms of products that implement digitally project able sound are commercially available today. The first is a set of one or more line arrays, or columns or rows of speakers, which working together are capable of producing clearer sound in a controlled area with fewer total speakers [1]. As previously explained, these are typically implemented in medium to large scale areas and systems. The second form is that of a typically horizontal array of speakers that use similar but more complex techniques to direct and bounce sound around a room in order to produce an effect similar to that of surround sound systems. These are available and appropriate for a range of room sizes that may be found in any given house or apartment, but implement proprietary and protected algorithms which would make a similar project inadvisable given cost, time, and complexity constraints.
2.1 Renkus-Heinz Iconyx Steerable Array System
The Renkus-Heinz Iconyx arrays are assembled from any number of standardized eight-channel speaker towers, specifically called the IC8, and digital amplifiers found in any number of their similar products [2]. A graphical interface called BeamWare is especially effective in illustrating sound distribution in a number settings based on room size and audience distribution [2]. The factors that makes their products unique is built-in digital signal processing engines and accompanying software that allows a user or technician to choose a number of specific settings to maximize sound clarity and minimize echoing and distortion. These effects are especially noticeable and necessary in public areas where acoustics were not observed in construction. Examples are museums, courtrooms, airports, theatres, and places of worship. However, these particular models are not appropriate for applications in homes due to their size, design, and cost.
2.2 Yamaha YSP-1
The Yamaha YSP series of digital sound projectors produces a surround sound environment with only one wall mounted unit. By employing either 28 or 42 individual sound projectors, depending on the specific product model, the YSP bounces some sound onto adjacent and opposing walls and some directly to where the user is expected to be [3]. A video output brings up the configuration settings for the sound projector. A quick setup is possible to appeal to inexperienced users: it is possible to get started by choosing the closest match to room shape, dimensions, and user position. A number of limitations are still present with the series: a lack of a subwoofer makes production of lower sound frequencies ineffective, a relatively low power output of 120 W is significantly less than the 500 W produced by a good traditional system, and the total cost of the unit is rather high at $1500 per unit. Overall, the series is not quite as effective as a full set of speakers, but can find application where a very unobtrusive system is required. Many of the mentioned shortcomings may also be resolved as the series matures.
3.0 Project Packaging Specifications
The packaging for this project can be divided into two sections, the structure and supporting elements of each tower and the user display elements of the control box. The body of each speaker tower will be constructed out of medium density fiberboard (MDF). MDF is dense, flat, stiff, and has no knots or voids [4]. It is very easy to machine, and cut edges will not tear like plywood. Overall, the substance is very dense, will not shake or rattle if properly mounted, is well acoustically damped, and is the standard material of choice for speaker enclosures. The power supply, digital processor, and circuit board will be mounted within the rear base of each speaker with standoffs and appropriate fasteners to make the electronics stable enough for any handling of the speakers. The speaker arrangement is chosen for the option to direct sound both vertically and horizontally. Each individual speaker is mounted into the frame of the tower with appropriate screws and an insulating adhesive. A subwoofer is included at the base of the tower. It is also notable that the nature of the speakers and insulating adhesive used, each speaker and subwoofer will be in its own isolated “chamber”, preventing vibration from interacting between speakers. 9” is the minimum width of the tower to accommodate the subwoofer and speaker arrangement, and a tower height set between 3’ and 4’ is an acceptable compromise between tower size and a minimum height to effectively project sound to specific regions of the room. A 12” square base should provide sufficient room for the subwoofer and included electronics. The control box will likely be a plastic enclosure with a Lexan plate protecting a 5.5” LCD monitor and two sets of capacitance touch buttons. Assembly can be completed with relatively simple tools including a circular and jig saw, drill, soldering iron, and wire cutters and strippers. The weight of the speaker towers can be estimated at 50 to 60 lbs each. The majority of this will be for the enclosure, which should weigh roughly 35 lbs. Dense and possibly thick versions of MDF will be used in order to prevent resonating or shaking. The power supply, subwoofer, and individual speakers will make up the majority of the remaining weight estimate. As shown in the bill of materials in Appendix B, the expected cost of each tower is about $510.
4.0 PCB Footprint Layout
The figure in Appendix C illustrates the PCB layout required in each speaker assembly. The most important factor in placement of the parts and headers is the accessibility of the digital amplifiers, the DSP communication and programming headers, and the audio input connection. The DSP and codec chips have the form of a low form quad pack [5], [6] while each of the eight digital amplifiers are shrink small outline packages. The DSP headers make the SPI and JTAG pins available. The only restriction on the total board size is that it must fit within the 12” by 9” space at the base of the tower. If a PCB is required for the control box, the microcontroller will need a 28 to 40 pin dual in-line package or quad pack depending on the specific model and package choice [7]. It will require headers to the SPI, reset pin, and serial pins. Connectors for the infrared module, capacitance touch buttons, and a possible multiplexer will also need to be included. These consist of standard I/O ports and are variable. The main constraint is that the board and the ezVID video module, a 2” square board [8], must be able to fit in the box.
5.0 Summary
By producing a versatile digital sound projector with a range of configuration options to enable users of all skill levels, this project brings a product previously only available to public or industrial groups into the consumer market. The design constraints require a set of speaker towers and control center that are no more obtrusive than a traditional unit, but provide high quality sound with strong customization of where the output is directed and digitally modified. At the same time the speakers should be sturdy, reasonably priced, and incorporate aesthetics as is possible.
List of References
[1] Audio Engineering Society, “Directional Radiation Characteristics of Articulating Line Array Loudspeaker Systems,” [Online Document], November 30, 2001, [cited January 24, 2007], http://www.alfordmedia.com/linearray/AES_DirRadiation.pdf
[2] Renkus-Heinz, “ICONYX Product Page,” [Online Document], unknown publication date, [cited January 24, 2007], http://www.renkus-heinz.com/loudspeakers/iconyx/index.html
[3] Audioholics.com, “Yamaha YSP-1 Digital Sound Projector: A Milestone in Home Theater History,” [Online Document], March 05, 2005, [cited January 24, 2007], http://www.yamaha.com/yec/ysp1/resources/Yamaha_YSP1_12pgs.pdf
[4] Wikipedia, “Medium Density Fibreboard,” [Online Document], January 23, 2007, [cited January 24, 2007], http://en.wikipedia.org/wiki/Medium_density_fiberboard
[5] Analog Devices, “ADSP-21262 Datasheet,” [Online Document], August 2007, [cited January 24, 2007], http://www.analog.com/UploadedFiles/Data_Sheets/ADSP-21262.pdf
[6] Analog Devices, “AD1835A Datasheet,” [Online Document], December 2003, [cited January 24, 2007], http://www.analog.com/UploadedFiles/Data_Sheets/AD1835A.pdf
[7] Atmel, “ATmega16 Datasheet,” [Online Document], October 2006, [cited January 24, 2007], http://www.atmel.com/dyn/resources/prod_documens/doc2466.pdf
[8] Multilabs, “ezVID Serial Video Module,” [Online Document], 2004, [cited January 24, 2007], http://www.jameco.com/Jameco/Products/ProdDS/355856MAN.pdf
Appendix A: Project Packaging Illustrations
Appendix B: Project Packaging Specifications
Qty
/ Total CostDigi-Key / Atmel / ATMEGA164P-20PU / 8-bit microcontroller / 4.08 / 1 / $4.08
Analog Devices / Analog Devices / ADSP-21262 / SHARC DSP / 28.32 / 2 / $56.64
Digi-Key / Analog Devices / AD1835AASZ-ND / CODEC 2ADC/8DAC / 14.33 / 2 / $28.66
Digi-Key / EPSON / SGR-8002DC-PCC / 25 MHz Oscillator / 5.15 / 2 / $10.30
Digi-Key / EPSON / SGR-8002AC-PCC / 12.288MHz Oscillator / 6.25 / 2 / $12.50
MCM / MCM / 58-9785 / Power Supply / 16.95 / 2 / $33.90
Digi-Key / TI / TPA3001D1 / 20W Class D Loudspeaker Amp / 5.00 / 16 / $80.00
MCM / MCM / 50-6273 / 55W Subwoofer Amp / 24.95 / 2 / $49.90
Digi-Key / Quantum / E240B / 4 Touch Button Kit / 19.00 / 2 / $38.00
Jameco / Muxlab / EZVID / ezVID Serial to TV Module / 60.00 / 1 / $60.00
MCM / Intec / 58-10535 / 5.5” Color LCD Monitor / 49.95 / 1 / $49.95
Mouser / Vishay / TSOP36 / 36kHz IR Sensor / 1.26 / 1 / $1.26
Parts Express / Onkyo / 269-566 / 2” Full Range Loudspeaker / 1.25 / 16 / $20.00
Klipsch / Klipsch / 8” High Excursion Subwoofer / 20.00 / 2 / $20.00
Home Depot / HD / MDF Wood for Loudspeaker Enclosure / 40.00 / 1 / $40.00
Home Depot / Lexan for touch display / 4.00 / 1 / $4.00
TOTAL / $509.19
Appendix C: PCB Footprint Layout
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