Digital Audio Evolution ENSC 340 Proposal: The idac (Digtal Audio Cassette) Submitted By Contact Submitted To Digital Audio Evolution Paul Gurney, Bill England, Scott Wakelin, Michael Hutchison Paul Gurney School of Engineering Science Simon Fraser University ptgurney@sfu.ca Andrew Rawicz School of Engineering Science Simon Fraser University Steve Whitmore School of Engineering Science Simon Fraser University Date September 20 th, 1999
Executive Summary Millions of people are downloading music from the Internet every day. The idac (Internet Digital Audio Cassette) allows them to enjoy this digital audio using their existing car stereos and walkmans. The idac is used just like a regular audio cassette, except that it sounds much better, and can store digital audio from the Internet. As memory sizes continue to increase, it will be possible to store hundreds of minutes of CD-quality audio on the idac. Emerging Internet access technologies such as ADSL and cable modems will allow users to download songs almost instantly. Furthermore, once security concerns are worked out, major recording labels will sell music directly over the Internet. Most cars sold in North America in the past 15 years are equipped with tape players, and there is a perception that upgrading car stereos is a costly and time-consuming process. Therefore, there will be a huge market for a digital audio device that can be used in a standard tape player. Digital Audio Evolution consists of four third-year Engineering students from Simon Fraser University in Burnaby, British Columbia. The idac project is budgeted to cost approximately $300, which we hope to attain from sources as detailed in the funding section. The project will be researched, designed, and developed over a 13-week period starting September 6 th and ending December 12 th. The end goal of the project is to have a working proof-of-concept device. ii
Table of Contents Executive Summary...ii Table of Contents...iii List of Tables... iv List of Figures... iv 1 Introduction...1 2 System Overview...2 3 Design Issues...3 3.1 Accepting User Input...3 3.2 Computer Interface...3 3.3 Power Supply...3 3.4 Data Format...3 3.5 Memory...3 4 Proposed Design Solution...4 5 Information Sources...5 6 Estimated Budget...6 7 Funding Sources...7 8 Schedule...8 9 Team Organization...9 10 Conclusion... 10 11 References... 11 iii
List of Tables Table 1 Estimated Project Budget...6 Table 2 Project Milestones...8 List of Figures Figure 1 Overview of the idac System...2 Figure 2 Project Gantt Chart...8 iv
1 Introduction Virtually every car, new or old, has a standard cassette player in it. To be able to listen to CD music, without having an expensive CD player installed, car owners must buy a tape adapter for their cassette player that lets them connect a portable CD player to their cassette player. This adapter can be very unsightly and normally involves wires running from the tape player to the portable CD player, leading to a clumsy setup. The idac will be a device that functions just like a normal tape cassette, with the exception that it stores music in digital MP3 format. An idac owner need only store their music on the device (using a standard personal computer) and then insert it into the cassette player to listen to their music. No wires, no adapters, no fuss. The idac is a device that stores MPEG2 Layer 3 (MP3) music in non-volatile RAM. The device can be connected to a standard personal computer for programming, and can be used like a standard tape cassette in any tape player. Internal batteries, requiring no additional wire connections supply power. Our project objective is to build a working proof of concept device by December. The main function of this document is to detail the method used to build the prototype. Possible design approaches, sources of funding, project scheduling and the team s organization, are discussed in detail in the following sections. 1
2 System Overview Figure 1 shows the basic function of the idac system. Digital audio (e.g., a MP3 or WAV file) is downloaded to memory inside the casette. The cassette can then be placed in a standard cassette player (e.g. car stereo or walkman). The digital audio is converted into a magnetic field which is read by the play-head in the cassette player. Digital Audio Magnetic Field Figure 1 Overview of the idac System The ideal system consumes very little power, so that it can run for several hours (or days) on a battery. All the components will fit inside of the standard tape cassette form factor. 2
3 Design Issues There are many issues to consider in designing this project. This section details possible solutions to perceived high-level design problems that will be faced by the design team. 3.1 Accepting User Input There needs to be a way for the user to control which audio track the cassette should be playing. One way to do this is to provide a wireless remote control, which can send signals to the cassette. Another method is to detect the speed of the cassette wheels. If the wheels are moving slowly (play mode), the cassette can play the selected track. If the wheels are moving quickly (Fast-forward or Rewind mode), tracks can be skipped. 3.2 Computer Interface The parallel or serial port of a personal computer could be used to download audio data. This would require special software running on the PC. For quicker downloads, ISA or PCI cards could be provided. The cassette could be inserted into a docking station connected to the PC to facilitate transfers. Another alternative is to use a Universal Serial Bus connection, which can supply power to devices to which it connects. This would reduce the power requirements for the device while transferring data, and may also provide a way to recharge the internal batteries in the device. 3.3 Power Supply The cassette will need to be powered using batteries. AAA batteries fit in a standard cassette form factor, as do small outline lithium ion batteries. Both types of batteries are rechargeable. AAA batteries, however, have a much lower power density than lithium ion batteries. Recharging could take place while the cassette is downloading audio data from the computer. It would also be possible to obtain power from a micro-generator coupled with the rotating wheels and tape guide. In an ideal ultra-low power implementation, this generator would eliminate the need for a battery. More realistically, the generator would reduce the load on the battery, allowing it to last longer. 3.4 Data Format There are several digital audio formats ranging from the very complex with low bitrates (e.g. MP3, Microsoft ASF) to the very simple with high bitrates (e.g. ADPCM, Raw audio, WAV) that could be supported. 3.5 Memory Data storage must be robust enough to maintain data integrity over long time periods. Flash [2], [3] RAM or NVRAM (volatile RAM with a lithium backup battery) could be used for this type of data storage. 3
4 Proposed Design Solution The goal of our solution is to provide a proof of concept for the system. We will focus on implementing the critical features without attempting to fit the components into the form factor of a cassette, or powering the device with a low power battery. Once the concept has been proven, size and power constraints can be met through straightforward Engineering changes. These changes will require a large amount of capital investment, which we hope to obtain using our proof of concept device. User input will be entered using simple push button switches in the proof of concept device, where the push buttons will simply feed the device an On, Off, Rewind, or Fast Forward signal. At a later time a wireless remote control, or tape reel speed sensing device will be developed. The interface to a personal computer will be through simple software with a text-based user interface that outputs information to the parallel port. Standard laboratory power supplies will provide power to the proof of concept device. The final power supply design will be left for the full device implementation. Data for the proof of concept device will be a standard pulse-code-modulated (WAV) file stored in the memory devices. Time permitting an MP3 decoding algorithm may be developed for the onboard controller, at which point data will be in standard MP3 format. The memory for the proof of concept device will consist of 16 MB of Flash RAM, holding approximately 16 minutes of music. 4
5 Information Sources Information for the project will be obtained from a variety of sources as required. The key sources of information will include application notes from the manufacturers of devices that we are using, reference books, textbooks, the Internet, and product data sheets. In addition information may be found in periodical publications, and science journals. A particular team member is working with a digital video design team on co-op and has excellent contacts for information regarding MPEG2 encoding and decoding. This information resource will be used as needed. 5
6 Estimated Budget Table 1 details the expenses that we intend to incur during the project. Table 1 Estimated Project Budget Required Materials Estimated Cost ($) Flash RAM <nil> Obtained from Intel as a sample Field Programmable Gate Array <nil> Obtained from HP as scrap Digital to Analogue Converter <nil> Obtained from Crystal as sample Magnetic Transducers $50 Prototyping Circuit Board Materials $50 Switches for User Input $30 Output Amplifier $20 Miscellaneous (tools, cables, etc) $150 Estimated Total $300 With design changes, we expect that this budget could change by approximately $100. This change will result from changes in the parts that we require. 6
7 Funding Sources Digital Audio Evolution intends to obtain funding for the project through the following two sources: The Wighton Development Fund The Engineering Undergraduate Student Society Endowment Fund Dr. Rawicz will be used as a contact for obtaining funding from the Wighton Development Fund. A proposal will be submitted to the Engineering Undergraduate Student Society at a general meeting for funding from the Endowment Fund. It is believed that funding will be readily available due to the high probability of this project being a market success. Should additional funding be required at a later date, additional requests to funding organizations will be made, with team members making up the difference as required. 7
8 Schedule Below is a Gantt Chart detailing the tasks involved in completing the project. The output of each task is a milestone. The project milestones are as follows: Figure 2 Project Gantt Chart Table 2 Project Milestones Milestone Target Date Project Selection September 7 Project Proposal September 20 Progress Report Number 1 October 4 Functional Specification and Project Research October 18 Design Specification November 8 Design Complete November 15 Prototype Complete, Progress Report 2 November 22 Design Specification Updated to Reflect Prototype November 29 Web-site Complete November 30 Process Report, Project Completed December 7 8
9 Team Organization The project team is composed of four Engineering students from Simon Fraser University. Each team member has taken the time to understand the project goals, and shares the aligned vision of the team. Team dynamics are such that a regular weekly meeting has not been scheduled; instead team members communicate through email, coordinating design efforts as needed. The project milestones are clearly understood and the duties of each team member are decided upon as needed, using the email forum. Paul Gurney is the team leader providing overall direction for the team. Bill England is the team financial expert, ensuring that all financial aspects of the project are dealt with. Scott Wakelin is the team system design expert, ensuring that the overall system design is appropriate. Michael Hutchison is the low level design expert, ensuring that the low level system design and implementation are appropriate. In addition to these duties each team member actively participates in documentation creation, and lab work. Goals have been set by the team to ensure an aligned vision. These goals include creating a positive environment for learning and personal development, creating an environment where team members can excel, and providing strong constructive feedback to team members when appropriate. It is understood that the opinion of each team member is equal in value to others, and that each team member has experience in differing areas leading to strengths that should be nurtured and encouraged. All team members are equal and each has the right to speak their mind when they feel it is appropriate. Digital Audio Evolution is confident that through successful teamwork, this project will be completed as detailed. 9
10 Conclusion The proposed idac will allow users to store digitally compressed music in a device that allows playback in any standard cassette player. This approach is both unique and technologically innovative. We believe that we have found a non-exploited market segment, to which we can provide a high quality product. This approach avoids having individuals purchase expensive and bulky portable CD player adapter kits. Our proposed schedule clearly illustrates that the project can be completed within the specified time frame for ENSC340. The budget clearly details the expenses that will be incurred during the project. Design problems have been considered, and proposed solutions have been provided for the high-level design considerations. Digital Audio Evolution is confident that it can complete the described project on time and on budget. We are confident that by December 1999, we will have proven the concept of the idac. 10
11 References [1] Rioport, <www.rioport.com> [2] Intel, <www.intel.com/design/flash/isf/what.htm> [3] Intel, <www.intel.com/intel/annual98/about.htm> 11
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