EE 477 Final Report
ECE 477 Final Report
Spring 2004
TEAM CODE NAME: TEAM MIXMASTERS TEAM ID: 7
TEAM MEMBERS (#1 IS TEAM LEADER):
#1: CLEWIN MCPHERSON SIGNATURE: ____________________ DATE: _________
#2: JIM BAUERLE SIGNATURE: ____________________ DATE: _________
#3: RUTH DEVLAEMINCK SIGNATURE: ____________________ DATE: _________
#4: NICK SCHNETTLER SIGNATURE: ____________________ DATE: _________
REPORT EVALUATION
|Component/Criterion |Score |Multiplier |Points |
|Abstract |0 1 2 3 4 5 6 7 8 9 10 |X 1 | |
|Project Overview and Block Diagram |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Team Success Criteria/Fulfillment |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Constraint Analysis/Component Selection |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Patent Liability Analysis |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Reliability and Safety Analysis |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Ethical/Environmental Impact Analysis |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Packaging Design Considerations |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Schematic Design Considerations |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|PCB Layout Design Considerations |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Software Design Considerations |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Version 2 Changes |0 1 2 3 4 5 6 7 8 9 10 |X 1 | |
|Summary and Conclusions |0 1 2 3 4 5 6 7 8 9 10 |X 1 | |
|References |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Appendix A: Individual Contributions |0 1 2 3 4 5 6 7 8 9 10 |X 4 | |
|Appendix B: Packaging |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Appendix C: Schematic |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Appendix D: Top & Bottom Copper |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Appendix E: Parts List Spreadsheet |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Appendix F: Software Listing |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Appendix G: User Manual |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Appendix H: FMECA Worksheet |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
|Technical Writing Style |0 1 2 3 4 5 6 7 8 9 10 |X 5 | |
|CD-R of Website Image |0 1 2 3 4 5 6 7 8 9 10 |X 2 | |
| |TOTAL | |
TABLE OF CONTENTS
Abstract
An MP3 turntable. The unit will load MP3’s from a Compact Flash card and then allow the user to manipulate the loaded file as though it was a vinyl record on a turntable. An LCD display, various pushbuttons, a slide potentiometer, an RPG, and a turntable platter will comprise the user interface.
1. Project Overview and Block Diagram
1.1 Project Overview
The B.E.A.T.S. (Breakthrough Electronic Audio Turntable System) will manipulate the playback of an MP3 using a rotary pulse generator and a side potentiometer. MP3’s are made available to the player through the use of an interchangeable Compact Flash card on which the files may be stored. As the user rotates a turntable platter, an RPG at the base of the platter will provide interrupt data to the main processor, which will interpret the movement. The processor will, in turn, translate that movement for application to MP3 playback. Device status and user interface will be provided by an LCD display, a linear potentiometer, and various pushbuttons. As songs are played and manipulated, the LCD display will track the features being used as well as song progress. An MP3 decoder as well as a D/A converter will perform the actual playback. The pushbuttons will allow the user to select a song to load as well as initiate play, pause, stop, skip, cue, and loop. The slide potentiometer will allow the user to apply constant tempo changes. The entire system will be powered by an inexpensive 5 VDC power supply.
1.2 BLOCK DIAGRAM
2. Team Success Criteria and Fulfillment
1. Ability to input a velocity vector using the RPG
a. THIS CRITERION WAS MET IN FULL.
b. THOUGH THE MP3 FAILURE PREVENTED US FROM DEMONSTRATING THE APPLICATION OF THE DATA GATHERED FROM THE RPG, WE WERE ABLE TO DISPLAY THE RESULTS OF POLLING THE DEVICE TO THE LCD.
2. ABILITY TO OUTPUT STANDARD MP3 PLAYBACK
a. THIS CRITERION WAS NOT MET.
b. WE BELIEVE THE NUMBER OF ERRORS ON OUR PCB DIRECTLY CONTRIBUTED TO THIS MODULE’S LACK OF COMPLETION.
3. ABILITY TO READ DATA FROM A COMPACT FLASH READER
a. THIS CRITERION WAS NOT MET.
b. WE BELIEVE THAT THE NUMBER OF ERRORS ON OUR PCB DIRECTLY CONTRIBUTED TO THIS MODULE’S LACK OF COMPLETION. THE MAJOR ERROR RELATED TO THIS MODULE WAS MISLABELED FOOTPRINT WHICH LED TO A FAULTY LAYOUT AND, IN TURN, A FAULTY PCB. THE HEADER WAS SUBSEQUENTLY FLY-WIRED, BUT TO NO AVAIL.
4. ABILITY TO DISPLAY INFORMATION CONCERNING MP3 PLAYBACK USING AN LCD DISPLAY
a. THIS CRITERION WAS MET IN FULL.
b. THOUGH REAL-TIME MP3 PLAYBACK DATA WAS NOT AVAILABLE, WE WERE ABLE TO DEMONSTRATE THE FUNCTIONALITY OF THIS MODULE USING HARD CODED VALUES.
5. ABILITY TO MANIPULATE THE MP3 PLAYBACK
a. THIS CRITERION WAS MET IN FULL.
b. THOUGH MP3 PLAYBACK WAS NOT AVAILABLE, WE WERE ABLE TO DEMONSTRATE THE FUNCTIONALITY OF THIS MODULE USING THE PYTHON PROTOTYPE SCRIPT ON A SUN STATION.
CONSTRAINT ANALYSIS AND COMPONENT SELECTION
The design constraints in this project are logically divisible into three classes: data transfer, user interface, and packaging. Data transfer constraints surface as a result of compact flash usage. User interface constraints are generated by ergonometric considerations, the need for sufficient tactile feedback, and the gathering of real-time data. Since the ultimate goal is to reproduce the look and feel of a vinyl turntable, packaging constraints arise because the entirety of the system must fit inside a portable case. Finally, as with most design projects, the primary constraint above all others is project cost: the project most operate within a collegiate student’s budget.
3.1 Constraint Analysis
The MP3s will be loaded into the system from a compact flash card, an interface that does not support data streaming. Furthermore, manipulation of the file in play requires that a large portion of the song be readily available to prevent gaps in playback. These restrictions introduce the first design constraint: the need for large microprocessor memory banks. The memory capacity of the chosen microprocessor must be at least 512 KB to accommodate the song buffer in addition to other dynamic allocation for function calls and local variable declarations. Given this much storage, compact flash data transfer restrictions are accommodated as are the restrictions imposed by the need for seamless playback.
The user operating the turntable will most likely be standing over the device. The line of sight from the user’s eyes to the system display will therefore be, on average, at least 3 feet. This introduces the second design constraint: the need for a system display large enough to be readable at a distance of 3 to 4 feet.
The system display is not the only portion of the user interface that generates design constraints. Though many of the features can be implemented with pushbuttons, (play, pause, stop, cue, and loop) the pitch/jog control must give the user a legitimate sense of moving a record back and forth. This necessity fosters two design constraints: the need to provide adequate tactile feedback to the user and the need to gather rotational data as a velocity vector.
The packaging design constraint goes somewhat hand-in-hand with the user interface constraint of adequate tactile feedback. Not only does the user interface need to be comparable to that of a standard vinyl turntable, but it also needs to be compact enough to be portable like all other DJ equipment.
2. Rationale for Component Selection
Microprocessor: As was previously stated, a design requirement for the microprocessor was that have enough memory to accommodate loading at least 30 seconds of an MP3. According to its data sheets, the Rabbit 2120 microprocessor core module comes with 512K of SRAM and can accommodate 6 additional off chip memory modules. The Ultimodule SCM220, on the other hand, offers 8MB of SRAM as well as 1MB of parallel flash 16MB of serial flash. Both processors have an adequate number of input pins for the peripherals that the project requires, but the Ultimodule SCM220 has limited support. Though it has less main memory, the Rabbit 2120 was selected due to its proven technology and widely available support.
Rotational Sensors: Original proposals for this project called for the use of an array of phototransistors (Panasonic SSG PNA1401L) in conjunction with a focused LED beam to sense rotational motion. The beam would be mounted on the underside of the turntable platter while the transistors would be installed along the inner wall of the platter bay. As the platter would rotate, the beam would pass over each transistor, and then the transistor data would be in turn fed to the processor for interpretation. While this scheme made sense on paper, the reality of project timing constraints (one semester for production) and budgetary constraints (phototransistors are roughly $4 a piece, making an array of them upwards of $40, not counting how many might be damaged in prototyping) motivated a search for cheaper solutions. The resulting find was a Grayhill Rotary Pulse Generator (series 25L). Mounted at the base of the turntable platter, this inexpensive device will provide 36 discrete of data points per rotation in addition to directional indications. Selecting the RPG over the phototransistors simplified the gathering of rotational data while still allowing for easy interfacing to the tactile feedback mechanism desired.
System Display: Before considering line-of-sight/ergonometric issues, the display selected was the Crystalfontz CFAG12864B-TMI-V 128x64. The original thought was that a backlit display such as this would take care of any line-of-sight issues. The more it was discussed, however, the more it became apparent that backlighting wasn’t enough – if the font wasn’t big enough, the user would have to crouch over the display to read it. Judging that this was unacceptable, we chose the PJRC 24x8 MP3 player display. Though this model isn’t backlit (the backlit version of this model was over $100), the size of the font is considerably larger than that of the Crystalfontz model. To keep cost down, the number of characters that can be displayed is lower than that of the Crystalfontz, but it was decided that this was an acceptable tradeoff. An added benefit is that the PJRC model comes with a 12 key pushbutton board, a feature which simplifies our user interface significantly.
MP3 Decoder/Digital to Audio Converter: While these components do not contribute directly to the design constraints, they are an integral part of the design, and therefore merit mention. Initial plans called for use of the Micronas MAS 3507D MPEG Decoder in conjunction with the Micronas DAC 3550A Stereo DAC. These components were sold as a package from Micronas, and this was attractive from the standpoint that interfacing notes came with the package. It was later discovered, however, that the Micronas line of MPEG decoders was unreliable. We replaced that pairing with the ST STA013 MPEG 2.5 Decoder and the Cirrus Logic CS4334 Stereo D/A Converter. The ST MPEG Decoder is noted as interfacing well with the Cirrus D/A Converter, which was again attractive. In addition, the ST MPEG Decoder features a variable speed internal clock, a feature which should make tempo variations fairly simple to implement.
3. Patent Liability Analysis
One of the components of building a product for manufacture is to examine the possible patent infringements. The individual components were purchased intact and the manufactures of these components have already resolved any patent issues. We do not need to examine infringement problems for these. The areas that need to be examined are the functions that are being implemented by the digital turntable. Possible infringement problems are analyzed below. [29]
4.1 Results of Patent Search
In examining the patents accessible through , there were no patents found in which literal infringement was committed. However there are a few patents which have similar functions.
The first patent examined is patent 6,618,329: Digital audio signal player having a simulated analogue record. This patent covers a control element which is electronically connected to an audio signal processor and a microprocessor. The microprocessor can detect the difference between a glitch and an original signal. The control element has a sensor for sensing the rotating speed and direction so as to make the audio signal processor to process and send out the data according to the movement of the control element. Therefore the user can rotate the control element with the hands to decide on the playing speed and direction so as to play the music with changed tone and speed. The idea of this patent is very similar to ours, except that this patent uses a CD on a CD player instead of MP3’s on a compact flash card. It also does not need to use the LCD screen that we use for song selection.
ABSTRACT: A digital audio signal player having a simulated analogue record includes a laser pick-up used for reading the data of an analogue CD, a microprocessor, a digital audio signal processor electrically connected to the microprocessor, a digital/analog converter electrically connected to the audio signal processor, and a turnable control element. The data of the CD is stored in a RAM of the audio signal processor. The control element is made of conductive materials, and electrically connected to both the audio signal processor and the microprocessor, and can send a glitch to the microprocessor when touched by the user's hands. The microprocessor will make the audio signal process and send out the data on detecting that the difference between the glitch and an original signal exceeds a preset amount. The control element has a sensor for sensing the rotating speed and direction thereof so as to make the audio signal processor to process and send out the data according to the movement of the control element. Thus, the user can rotate the control element with the hands to decide on the items of the music and the playing speed and direction so as to play the music with changed tone and speed. The music is played in the original normal way as soon as the user removes the hands from the control element for disappearance of the glitch. [28: 6,618,329]
The second patent that was analyzed is number 6,541,690: Scratch effect controller. This is a rotary encoder having the physical characteristics of a vinyl phonograph disc on a properly prepared turntable. The encoder may be used in virtually the same manner as a conventional record to create scratch effect in a digital signal being supplied form a digitized audio signal source such as a CD, mini-disc, digital audio tape, data file, or any other source of a digital signal. Speed and direction information from the encoder are used as inputs to a digital signal processor so that scratch effects may be simulated in the digital signal.
ABSTRACT: There is provided a rotary encoder having the physical characteristics of a vinyl phonograph disc on a properly prepared turntable. A disc jockey (DJ) may intuitively use this encoder in a virtually identical manner to a conventional record to create scratch effects in a digital signal being supplied from a digitized audio signal source such as a CD, mini-disc, digital audio tape (DAT), data file or any other source of a digital signal. Speed and direction information from the encoder are used as inputs to a digital signal processor so that scratch effects typically produced by the manipulation of a vinyl record on a turntable may be simulated in the digital signal. [28: 6,541,690]
The third patent examined is number 5,146,833: Computerized music data system and input/out devices using related rhythm coding. This patent deals with the concept of taking different musical inputs and converting the rhythm and pitch to specified values.
ABSTRACT: A computerized musical instrument system has a processing system for converting multiple modes of music data input into relative rhythm coded data in the format of pitch codes and relative rhythm codes for designating respective types of rhythm elements, including the pitches, as they occur in the beats or other basic music intervals of a music piece. The relative rhythm codes represent the relative proportions by which the designated rhythm elements divide each beat. In a relative rhythm coding mode, pitch and rhythm data are entered via a keyboard and relative rhythm code and control code keys. The music data may also be input in the form of MIDI formatted data, audio or digital sound input, real-time performance (key press) data, or optically scanned data from printed music notation. The instrument system can provide various forms of outputs including synthesized sound, a display or music notation, stored music data, printed output, and related audio and/or image effects. [28: 5,146,833]
After consultation with Dr. Meyer, patent liability for such items at the play, stop, fast forward, rewind, etc. buttons was not researched as these should be common enough not to have a patent.
4.2 Analysis of Patent Liability
Neither of these patents are infringed under literal infringement, however there is the possibility for infringement under the doctrine of equivalents.
The first patent allows for the manipulation of speed and direction of the digitized signal using an external control element. If one wished to argue that infringement did not occur, one could argue that this patent specifies the use of a CD for the digitized signal, while the digitized signal of Team 7 manipulates MP3’s, which is a different sort of manipulation all together. However the argument that it is still performing substantially the same function in substantially the same way is more valid. The digitized signal can still have the speed and direction altered and have a glitch placed on the music.
The second patent also allows for the manipulation of speed and direction of the digitized signal using an encoder, which the author of the patent suggests would be round and approximately the size of a turntable commonly used by disc jockeys manipulating vinyl records today. Similar arguments to those made for and against infringement of the first patent could also be made for and against infringement of the second patent.
The third patent discusses the alteration of the pitch and rhythm of an input music signal. Because the mixMaster’s project does not alter the pitch of the signal, this is not an area where infringement would occur. However, the project does alter the rhythm, or tempo, of the music. The patent discusses doing so in a very deliberate manner. The mixMaster’s project does so only in relative terms. The alteration of the tempo is accomplished by moving the slide potentiometer up and down or by rotating the platter. The user is not able to specify the number of beats per second or any other such information. The patent encompasses a broader range of concepts than is employed by the mixMaster’s project, however infringement does occur.
4.3 Action Recommended
The arguments which a lawyer would be able to present that our product would not be in infringement under the doctrine of equivalents would not be strong enough to merely avoid infringement. We would also not be able to alter our product sufficiently to avoid infringement. In this situation a deal would have to be reached with the holders of these patents, which could be very costly. Depending upon the cost in order to use these patents, the cost to manufacture the product, and the price at which we could sell it, the profit margin may not be large enough to warrant the manufacture of this product for sale. In that case, my recommendation would be to cease work on this product and redirect our energy. However if the profit margin were high enough we could pay the holders of these patents and produce the product for sale.
4. Reliability and Safety Analysis
The two linear regulators, the level converter, the RPG and of course, the Rabbit Processor are the most likely to fail and will be analyzed further.
5.1 LM340 3-Terminal Positive Regulators
λp = (C1 * πT + C2 * πE) * πQ * πL Failures / 10 ^ -6 Hours (from MIL-HDBK-217F Sec 5)[36]
MTTF = 1/λp
C1: 18 Bipolar Linear Transistors => .010
πT: Tj Max 100° C Bipolar => 16
C2: 3 pin DIP w/solder => .00092
πE: Ground Fixed => 2.0
πQ: Commercial => 10
πL: Greater 2 years => 1.0
λp = (.010 * 16 + .00092 * 2.0) * 10 * 1.0
λp = 1.62 Failures / 10 ^ 6 Hours
MTTF = ~617280 Hours or ~70 Years
5.2 LM2936 Ultra-Low Quiescent Current 3.0V Regulator
C1: ~20 Bipolar Linear Transistors (Not noted specifically, very similar to the LM340 => .010
πT: Tj Max 100° C Bipolar => 16
C2: 3 pin DIP w/solder => .00092
πE: Ground Fixed => 2.0
πQ: Commercial => 10
πL: Greater 2 years => 1.0
λp = (.010 * 16 + .00092 * 2.0) * 10 * 1.0
λp = 1.62 Failures / 10 ^ 6 Hours
MTTF = ~617280 Hours or ~70 Years
5.3 MAX3000 8-channel Level Translator
C1: 1184 Transistors => .060
πT: Tj Max 100° C Bipolar => 16
C2: 20 pin SMT => .009
πE: Ground Fixed => 2.0
πQ: Commercial => 10
πL: Greater 2 years => 1.0
λp = (.060 * 16 + .009* 2.0) * 10 * 1.0
λp = 9.78 Failures / 10 ^ 6 Hours
MTTF = ~102250 Hours or ~11.7 Years
5.4 Grayhill RPG 25LB10-Q
λp= (λb1 + πN * λb2 ) * πCYC * πL * πE (from MIL-HDBK-217F Sec 14)[36]
λb1: Lower Quality (Not Military) => .086
πN: 3 Contacts => 3
λb2: Lower Quality (Not Military) => .089
πCYC: Average Cycles per Hour => 1 (Average over lifetime of product)
πL: Load Stress Factor (exp(1.25)^2) => 12.18
πE: Ground Fixed => 3.0
λp = (.086 + 3 * .089 ) * 1 * 12.18 * 3
λp = 12.9 Failures / 10 ^ 6 Hours
MTTF = ~77519 Hours or ~8.85 Years
5.5 Rabbit 2000 Microprocessor
λp = (C1 * πT + C2 * πE) * πQ * πL Failures / 10 ^ -6 Hours from MIL-HDBK-217F Sec 5)[36]
C1: Die Complexity: 8-bit Digital MOS => .14
πT: Tj Max 75° C => .71
C2: 80 Pins => .0036
πE: Ground Fixed => 2.0
πQ: Commercial => 10
πL: Greater 2 years => 1.0
λp = (.14 * .71 + .036 * 2) * 10 * 1
λp = 1.71 Failures / 10 ^ -6 Hours
MTTF = ~584795 Hours or ~66.75 Years
5.6 Conclusion
All of the components were found to within tolerance seeing that the produce would move likely be obsolete in about 5 years. The weakest link in the design at a mean time to failure of about 9 years is the RPG simply because it is a mechanical device and take more wear then the electronics. These could be easily replaced in the field if any malfunctions were to occur.
5. Ethical and Environmental Impact Analysis
6.1 Ethical Analysis
The Institute of Electrical and Electronics Engineers (IEEE) has recognized the importance of a set of principles of right conduct for engineers and is committed “to accept responsibility in making engineering decisions consistent with the safety, health and welfare of the public, and to disclose promptly factors that might endanger the public or the environment”[41]. It is the duty of a design engineer to ensure that the product operates as specified and meets standards set by governing bodies.
The ethical challenges of B.E.A.T.S. can be grouped in four major categories
i. testing under a variety of operating conditions
ii. adding safety mechanisms
iii. providing cautions in user documentation
iv. placement of warning labels
The major challenge that we faced, however dealt with the incompleteness of the unit. If the unit had come to completion, these categories must be adequately addressed to ensure that B.E.A.T.S. operates safely under “normal” conditions and in the event of hardware and software failures.
6.1.1 Testing
According to John Copeland of Motorola Product Testing Services “A well thought out and aggressive test program is one of the most significant techniques to validate the design's integrity and ability to meet established usability requirements.”[43]. The next step in testing is a tradeoff between using standard tests for similar products and using tests based on an evaluation of the system for typical use and potential misuses. To aid in thorough testing, a combination of the two will be used to ensure that B.E.A.T.S. meets standards and addresses the exact usage and design that was implemented.
The power system of this design has three voltage conversions. This produces some thermal dissipation and to ensure that B.E.A.T.S is still safe to operate, thermal life tests will be done to determine the maximum temperature reached by the device over an extended period of continual use. In the event of excessive heat dissipation, the design will be tweaked to reduce the heat. The operation of the system will also be tested in the absence of integral components (slide, buttons, and turntable). This is to ensure that the device can still safely function in the event of a malfunction.
Though temperature and environmental conditions are not factors in this design, they still need to be considered in testing. To ensure performance under a variety of different temperatures, B.E.A.T.S. will be tested in low temperatures and high temperatures. Thermal shock and cycling tests are also recommended to ensure that there are no severe latent failures or material weaknesses that occur over time.
Humidity is also an important environmental condition to be tested. In high humidity, the tests are to see if moisture can be forced into components and thus cause undesirable variances. In low humidity, the test ensures that seal materials are not vulnerable to dry out or crack. [43]
In all devices, it is inevitable that it will be dropped and so a variety of drop tests will be performed during production to ensure its durability and reliability. Since B.E.A.T.S is a medium sized electronic device, the dropping height will not need to be more than two to five feet and would include a variety of surfaces. A vibration test will also be performed to ensure that the system functions effectively in conditions where there might be constant vibrations (a “jumping” club).
Software is an integral part of B.E.A.T.S. Code that simply “works” is not sufficient to satisfy the standards set by the ACM/IEEE-CS Joint Task Force on Software Engineering Ethics and Professional Practices, which states that “Software engineers shall ensure that their products and related modifications meet the highest professional standards possible.”[44]. It is in keeping with this standard that extensive test vectors will be applied to B.E.A.T.S to ensure that the system not only works, but can also perform satisfactorily when the software receives erroneous or illogical inputs.
2. Adding Safety Mechanisms
The current implementation of B.E.A.T.S. does not include any redundancies to compensate for any of the components failing. In addition to the placement of warning labels and cautions in the user documentation there are three additional important safety mechanisms that are part of our implementation of the system. The safety mechanism that is included is a pushbutton reset that reboots the processor. On restart the processor initializes the other components of the system resulting in the entire system being reset.
If time had permitted, the design would have been reworked to include a watchdog and a fuse. The watchdog which enables the system to be more self reliant by checking for software anomalies and the status of the I/O pins. This would allow for the system to recover from unpredicted failures during the operation [45]. The fuse in the power supply would prevent excessive current in the event of a short circuit. B.E.A.T.S. will continue to be monitored to ensure that it operates as specified. As “bugs” are detected, both the software and hardware components will be upgraded.
6.1.3 Placement of Warning Labels
It is important that the user be constantly aware of potential hazards of the system. Warning labels will be placed at the back and bottom of the system to admonish the user from opening the casing. It will also advise the user of potential shock as outlined by the U.S. Consumer Product Safety Commission (CPSC) [46]. The warning labels will also advise the user not to use the system around water sources and wet surfaces, since the components are sensitive to water. The LCD will also initially have a warning label to alert the user not to hit the LCD with sharp objects and to advise the user to read the user manual before operating B.E.A.T.S.
A warning label will also be placed on the power cord to inform the use of the power requirements (120 VAC 60Hz). This label will also caution users from pulling on the power cord. These and other relevant warnings will also be included in the user manual.
6.1.4 Providing Cautions in User Documentation
The user manual is very important in communication the operational characteristics and the design specifications to the user. A detailed setup procedure and description of the operational characteristics will be included in the user manual and the user will be encouraged to read the manual before operation.
Part of the IEEE code of ethics states that we are to “…be honest and realistic in stating claims or estimates based on available data” [41]. In keeping with that code, the user manual for B.E.A.T.S. will list potential hazards and warnings along with conditions for the optimal operation (bit rates and compact flash cards).
It is also important that the user be aware of ways to maintain the system in order to ensure correct operation. To ensure the user is aware of this, the user manual will contain information about the care, cleaning and storage of the unit.
It is important that the user not attempt to “service” or fix any potential problems that may occur. As such, the user manual will caution the user to contact a service center for any technical needs. A list of service centers will also be included. The warning labels that are placed on the device will also be placed in the user manual.
6.2 Environmental Analysis
“Within the broad portfolio of science and engineering for the new century, the environment is emerging as a vigorous, essential and central focus… The environment is no longer simply a background against which research is conducted, but rather the prime target for increased understanding.” [47]. This exert from a report from the National Science Board and emphasizes the importance that of environment in the manufacture, use and disposal of products, especially in an era where sustainable development has become such a pivotal issue. It is under these three main sections that the environmental analysis of B.E.A.T.S. is analyzed.
6.2.1 Manufacture
The major source of waste and the greatest environmental hazard in the design is due to the manufacture of the printed circuit board (P.C.B.). According to the Environmental Protection Agency (E.P.A.), typical wastes generated by the PC board industry are Industrial wastewater and treatment residues, Spent process baths, e/acids used for cleaning equipment, Copper sulfate crystals and Re-flow oil [48]. In addition to the PCB production, the propagation of the board also yields environmental hazards, in particular lead in the solder.
These are very common issues in the design process and may be reduced by the use of lead free solder and utilization of companies that actively seek to reduce the waste generated during PCB production.
6.2.2 Use
B.E.A.T.S does not, in its regular use, pose a direct negative effect to the environment. The unit does not produce any waste products and does not require the use of batteries. Like other electronic device, however, it does consume power. B.E.A.T.S. was designed and components selected to minimize power consumption. The device is only powered when it is in use and as such, it does not consume a lot of power.
6.2.3 Disposal
The disposal of B.E.A.T.S. is the part of the design process that has the more environmental impact. “E- waste” is the term that has been adapted for water due to electronic devices and is classified as a global issue and, if not addressed can overwhelm us with millions of tons of waste [49]. The major contributor to waste in B.E.A.T.S. is the plastic casing and the P.C.B. The P.C.B is not very simple to dispose since it is not biodegradable and thus cannot be dumped in a landfill.
The environmental effect of LCDs are not known, but it has been concluded that they are very difficult to biodegrade and only start to decay at 800 °C and it must be ensured that this temperature is maintained over a longer time period [50].
The plastic that provides the encasing of the unit can be recycled. This is also applicable for the buttons that will be used as part of the user interface.
In general, all these practices may be expensive and inconvenient for users to execute. It is for this reason, a recycling / disposal procedure will be stated in the user manual that allows for users to return the device to a service center to be recycled and effectively disposed.
6. Packaging Design Considerations
7.1 Analysis of Similar Commercial Products
Two products that are similar in functionality to the MP3 Turntable are GemSound’s BJL-1150, an older style vinyl turntable, and Pioneer’s CDJ-1000 Digital Vinyl Turntable.
The GemSound Turntable is 11.5” W x 3.5” H x 8.75” D. This is large enough for the platter with only a little room on each side of it. The MP3 Turntable will be larger (21” W x 3.5” H x 14.5” D) because it will have more features accessable from the top of the box. One of the nice features on GemSound’s turntable is a vertical slider. This can be used to control the base tempo of the record. The MP3 Turntable will also have a vertical potentiometer which will also be used to control the base tempo. Because GemSound’s turntable actually plays vinyls, it has an arm, however the MP3 Turntable does not actually play vinyls, so it will not have an arm. Another positive aspect of GemSound’s design is the use of a dustcover. The MP3 Turntable will also have a dustcover for protection during storage. GemSound’s turntable weighs 18 lbs, which is more heavy than the new MP3 turntable will be. One of the largest problems with this turntable is the media itself. Records are large, heavy to carry around, vulnerable to damage, and difficult to replace. [11]
Pioneer’s Digital Vinyl Turntable avoids using vinyls, and instead uses CD’s. These are more readily available and more compact. However, more songs can be stored into a flash card and carried more compactly. The Digital Vinyl Turntable contains many good functions. It has a jog dial in the middle that can be used to modify the tempo, buttons for play, pause, cue, etc. The MP3 Turntable will also have buttons with similar functions. However, instead of using a jog dial, the platter from an old vinyl turntable is being used. The jog dial actually has to be touched right at the edge in the little grooves provided, while the platter from the old vinyl turntable can be moved from anywhere on it’s surface. The use of the platter will give the MP3 Turntable a feel more like the vinyl turntables used by many DJ’s. The Digital Vinyl Turntable also has a vertical slider which can be used to vary the base tempo. [12]
Because both of these examples take the music off of a device with limited songs on them, there is no need to display a list of the available songs for selection. However the flash card will have more songs that can easily be remembered, so the use of an LCD to display information regarding the songs on the flash card is necessary. Because the turntable will be at least two feet away from the DJ’s head, the LCD needs to be large enough to be read from that distance. The LCD chosen is 4 1/2” W x 2 3/8” H. Another addition is a slot to insert the flash card.
2. Specifications for Packaging
Materials List:
Plywood
LCD
Buttons
Platter
Slot for Flash Card
Tooling Requirements:
Hacksaw
Basic Tools (Screwdrivers, etc.)
3. Packaging Weight and Cost
The original turntable purchased for use weighed approximately 15 lbs. After removing much of the interior components not being used, it weighs approximately 5 lbs. After adding the new components it will weigh approximately 7 lbs.
The cost of the turntable will be largely in electronic components. The components only being used for the packaging will be minimal: $5.50 for the old vinyl turntable and $10 for the plywood. This totals to less than $20 with tax.
7. Schematic Design Considerations
B.E.A.T.S is designed to use MP2s that are encoded at 128 kbps. Though other implementations can be used, they will not yield the optimal performance and sound clarity. The files are stored on a compact flash card and they are ready to be loaded into B.E.A.T.S. The user is able to select the song to be played from the compact flash card by using the keypad to browse the list of songs available, based on the title and artist. The song is loaded into the SRAM of the processor module and buffered during playback. The user selects the playback functions through the keypad interface and is able to perform advanced options through the use of the turntable platter and tempo slide. The mp3 decoded then decodes the file based on the playback options and displays the playback information and system status on an LCD.
8.1 Processor
The processor is an integral part of our design. The major factors in the selection of the RCM 2120 as the processor were the memory and the number of I/O pins available. The Rabbit has 40 parallel I/O lines (shared with serial ports), four serial ports (all of which can operate asynchronously in a variety of customary operating modes; two of the ports can also be operated synchronously to interface with serial I/O devices), numerous timers and counters (six all together) can be used to generate interrupts, baud rate clocks, and timing for pulse generation. [13] The timers allow for the rpg and mp3 decoder to be interrupt driven and the I/O pins allow for the easy connectivity of the other components since they can easily be accessed. [14]
8.2 MP3 Playback
8.2.1 Compact Flash
The Compact Flash interface uses 8 8-bit registers, 1 to write information into the Compact Flash and the other 7 to read information. [15] The file system on CompactFlash card is MS-DOS FAT, which allows the processor to interpret the data stored on the card. The processor will parse the data and determine the beginning of the song, then load it into memory and send it to the decoder in bursts based on the buffer size of the mp3 decoder (the size available varies depending on the encoding of the MP3). [16]
8.2.2 MP3 Decoder
The chip selected is the STA013. As stated before, B.E.A.T.S is designed for the standard encoding of 128 kbps for an MP3. The decoder operates at a frequency of 14.7456 MHz, which is receives from a crystal. [15] The output signal is passed into the D/A converter that is connected to RCA jacks. The design for this part of the circuit is taken from the data sheet for the CS 4334. [18]
8.3 Playback Manipulation
8.3.1 Rotary Pulse Generator
The rotary pulse generator (RPG) is the main interface for advanced playback manipulation and is mounted at the base of the turntable platter. The middle pin is connected to ground and the other 2 pins are connected to the microcontroller. The microcontroller interprets the direction of rotation of the platter (which tells the microcontroller to either advance or backtrack through the file) and the 36 discrete data points per rotation (which tells the microcontroller the time to be elapsed in advancing or backtracking) received from the RPG. [19]
8.3.2 Slide Controller
The slide controller is a slide potentiometer which is interfaced to the microcontroller through an A/D converter. The slide potentiometer selected is regularly used as type faders for audio mixers. [20] The output voltage from the potentiometer is connected to an A/D converter which sends discrete information to the processor based on the resistance of the potentiometer. [21] As the resistance increases, the A/D converter converts the resistance to a discrete value that tells the processor the desired tempo. The processor receives the value from the converter and repeats the number of frames from the mp2. (e.g. if the tempo is 2, the processor repeats each frame twice). When the resistance decreases, the processor drops frames based on the discrete value it receives from the A/D converter.
8.4 Visual Feedback
8.4.1 LCD & Keypad
Our system will display system status and file information on a 24x8 character LCD display. This display interfaces with a 12 key keypad that is used to control the operation of the player. [22] When a key is pressed, a connection is bridged between the corresponding row and column pins. The LCD is connected by a ribbon cable to a small adaptor board. The small adaptor board is for the assembled push button board and a 4 pin header with connections to ground and power and a receive and transmit connection to the processor. [23] This package has a voltage specification of 5V, which is available on the board. As the song is played or file structure viewed, the processor sends data to the LCD for the user to see.
5. Power Supply
Power will be supplied to our circuit by a 12VDC “wall-wart” power supply. Because of the voltage requirements of our circuit, this will be regulated to 5V and 3V by high efficiency voltage regulators. The 5V regulator will supply power to all the components, except the mp3 decoder which requires 3V. The power supply conversion includes of a regulating 0.1uF capacitor used to control any spikes or irregularities in the input signal from the power supply.
Since some of the components used in the design require 5V while others 3V, a level converter is used to translate between the two power domains. The MAX3000E level converter is selected since it provides 16 pins for 8 2-way signals to pass from one voltage domain to the other. [24]
8. PCB Layout Design Considerations
After reading the Motorola Application Note there were a few concerns that needed to be addressed about the board layout. First was to get the coupling capacitors as close to the connections as possible. This had also been mentioned numerous times in class and lab. Since the Rabbit Core Modules have these on board, the other chip were the main concern. There is also a 100uF capacitor across the incoming power connection to try to eliminate a ripple effect throughout the circuit.
The other thing mentioned in the Application Note was to place the crystal RC circuit as close to the chip as possible. This is so the clock it creates is as clean as possible.
Since the packaging for the design is so large, size was not a factor in our layout. Since the layout was can be so spread out there is no need to a ground plane or any other noise reduction. The voltage regulators were place away from any significant part, as to eliminate heat transfer. The power and ground traces were set at 12 M minimum and 70 M maximum. Normal signals were from 8 M to 12 M. The only problem encountered with these settings was running power and ground to the Rabbit Headers, since they are so tight together.
The Compact Flash header will be but cut away from the main board to be placed in a better spot for packaging. All the signals including ground and 10VDC will be run over an IDE cable. The 10VDC will be handled on this separate board by a voltage regulator. This is all self-contained on the separate board.
• During the debug process, we discovered several errors. Please refer to Appendix D.
9. Software Design Considerations
10.1 Software Design Considerations
Section 1: Memory Models
The microcontroller at the heart of B.E.A.T.S. is a Rabbit 2120 core module. This module was selected because of its extensive SRAM and reprogrammable flash. Because the design requires so much memory (for buffering sections of the file in play), main memory needs to be big enough to accommodate a large buffer in addition to the normal program constructs like stack space and local variable space. The RCM 2120 has 512KB of SRAM. We will use 256KB for the file buffer, leaving the remaining 256KB (actually a little less due to setup space needed by the Rabbit) for program space. To further optimize memory usage, no dynamic memory will be used by program code.
In addition to the SRAM, the RCM 2120 also has 512KB of Flash EPROM. This portion of the memory will store all the program code. Since the buffer consumes a considerable portion of the SRAM, the program code is written to reduce the number of function calls made (thereby optimizing the stack overhead needed to run programs). Because the EPROM is so expansive, the code can be written less modularly to accommodate this requirement.
All program code is written in Dynamic C. A key feature of using this coding environment is that the compiler handles all the memory mapping and layout at compile time, therefore alleviating some complexity from the software design considerations.
Section 2: Memory Mapping
As was previously stated, the Dynamic C compiler handles all of the messy memory addressing for main memory. The figure below (taken from the Rabbit User’s Manual) illustrates exactly how memory mapping is performed.
[pic]
Figure 10.1.1: RCM 2120 Memory Mapping
Figure 10.1.1 shows that all program code and constant values are stored in EPROM, while SRAM is reserved for active program memory (stack space, local variables, and dynamic memory).
Section 3: Initialization Routines
When B.E.A.T.S. is powered up, the first code executed are routines generated by the Dynamic C compiler for memory mapping. Following those routines are the first program code routines. These routines configure all the peripheral devices that comprise the B.E.A.T.S. interface as well as their associated variables (i.e. data direction registers). The following table shows where each peripheral is connected to the microcontroller.
|Peripheral |Location |
|CF |Data: Port A (Parallel I/O) |
| |Addr: Port D (Parallel I/O) |
| |Ctrl: Port D (Bitwise) |
| |Rddy: Port E (Bitwise) |
|A/D |Data: Serial C |
|RPG |Data: Port E (Bitwise) |
| | |
|MP3 Decoder |Data: Serial B |
| |I2C : Port E (Bitwise) |
| | |
|LCD |Data: Serial D |
Table 10.1.2: Peripheral Initialization
Section 4: Organization of Embedded Application Code
As was previously indicated, the most critical aspect of the program code is the demand streaming of audio frames to the decoder. Given this requirement, the following software design decisions were made:
|Code Module |Mode |
|CF Read |Interrupt |
|MP3 Send to Decoder |Interrupt |
|RPG |Interrupt |
|Tempo Controller |Polled |
|Song Selector |Polled |
|Push Button Array |Polled |
|LCD Refresh |Polled |
Table 10.1.3: Program Code Organization
CF Read and MP3 Send are handled by a single interrupt service routine. The RPG is handled by a second interrupt service routine which has a lower precedence than that of the CF Read/MP3 Send ISR. The rest of the modules are polled in a single main loop and their associated peripherals are serviced as needed.
10.2 Software Design Narrative
Section 1: Initialization Routine
This section of code is run once each time B.E.A.T.S. is powered up or reset. It performs the following sequence of operations:
• Configure LCD
• Load LCD with Splash Screen
• Configure CF Port
• Configure A/D Port
• Configure RPG Port
• Configure MP3 Decoder and associated Port
• Load LCD with Main Menu
Section 2: Interrupt Service Routine A Module
This section of code is run each time the MP3 signals that its buffer is near-empty or when a new song is selected for loading. It performs the following sequence of operations:
• Disable Interrupts
• Send MP3 data from sample buffer in main memory to the decoder until it is full
• Read data from the CF into the sample buffer until it is full
• Enable Interrupts
Section 3: Interrupt Service Routine B Module
This section of code is run each time the RPG is rotated. It performs the following sequence of operations:
• Disable Interrupts
• Sample the system clock
• Sample the RPG direction and count the number of changes
• Sample the system clock
• Divide number of changes by elapsed time
• Convert result to a speed-up/slow-down percentage
• Store speed-up/slow-down percentage in memory
• Enable Interrupts
The speed-up/slow-down percentage generated by this routine momentarily modifies the constant tempo change calculated by the Tempo Controller Module.
Section 4: Tempo Controller Module
This section of code is polled from the main loop when the active menu is the playback menu. It performs the following sequence of operations:
• Signal the A/D to sample the slide potentiometer
• Retrieve the sample from the A/D
• Convert the sample voltage to a speed-up/slow-down percentage
• Store speed-up/slow-down percentage in memory
The following two examples illustrate how the net percentage is used to affect a change in tempo: (1) If the net percentage is found to be +25%, the number stored is 4. As frames are sent to the MP3 decoder, every fourth frame is skipped, thereby increasing playback speed by 25%. (2) If the net percentage is found to be -25%, the number stored is -4. As frames are sent to the MP3 decoder, every fourth frame is send twice, thereby decreasing playback speed by 25%.
Section 5: Song Selector Module
This section of code is executed each time the user navigates to the Song Selection menu. It performs the following sequence of operations:
• Gather the first four filenames from the CF
• Update the LCD with the Song Selection screen and file listing
• Poll the button array
o If scroll is pressed, load the next file name, and poll the button array again
o If menu is pressed, return to the Main Menu
o If select is pressed, flag the file for loading and trigger the Interrupt Service Routine
Section 6: LCD Refresh Module
This section of code is executed at various times throughout the life of the program. It refreshes dynamic portions of the menus (such as time elapsed on Playback Menu) or the entire display when the user navigates to a new menu.
Section 7: Button Polling Module
This section of code is executed at various times throughout the life of the program. Some buttons are reserved solely for menu navigation (Up, Down, Left, and Right) and the rest of the buttons are used for playback (Play, Pause, Stop, Cue, and Loop). Navigation buttons affect the movement of cursors on the LCD. Playback buttons affect the playback of the file, and also are listed on the LCD when they are pressed.
10. Version 2 Changes
• Use Secure Digital Cards (SD) instead of Compact Flash Cards (CF): This change would simplify the audio file transfer because the SD is a serial interface as opposed to the IDE-like interface of the CF.
• Accommodate more types of digital media: Our design used MP2, but to use MP3 would require more complex code. To accommodate other types of audio files, we would need to add other hardware decoders to the current design.
• Increase the portability of the product by reducing the area of the layout: Our layout was intentionally spacious to accommodate debugging and any fly-wiring that might need to be done. Once all of the debugging work is completed, the layout could easily be consolidated.
• Display more information on the LCD: Include a help screen, the rest of the ID3 Tag information, and possibly even graphics. This would require more memory to be interfaced.
• More user control over the LCD: This change would include allowing the user to change the contrast and brightness, as well as selecting the display font.
• Add optional interface to a computer: This interface would allow the user to use B.E.A.T.S. as a human interface device in conjunction with industry standard D.J. programs such as Fruity Loops ©. The interface would also allow users to add or remove songs from the CF/SD card.
Summary and Conclusions
1
Though the project itself did not see total completion, the product of this semester’s hard work was a significant increase in the team’s general knowledge of the design process. We gained not only an appreciation for the design aspects of such a project, but also for the professional aspects. Above all, the need for teamwork and individual responsibility became paramount as the project progressed.
The milestones achieved this semester were numerous. Beginning with schematic and layout software, the team learned to describe circuits using computer-aided drafting tools. At this time, the skill of greatest importance was the ability to read and comprehend technical data sheets for the devices being used, and to translate that information into a formal design. Using the design produced in this phase, conceptual packaging was developed. In parallel with the packaging effort, software was conceived and prototyped using a Rabbit 2100 Development Kit. The products of this phase of the project were fully-functional software modules for the Rabbit processor, as well as authentic packaging and a PCB.
There were also many difficult lessons learned throughout the semester. Failure to properly examine the PCB layout prior to its fabrication directly contributed to the project not reaching completion. The errors in the layout translated to nearly 150 fly-wires and 40 hours of extra work. Given this scenario, the need for extreme parallel teaming became apparent. While part of our team focused on debugging the board, the rest of the team worked on finishing programming and completing assignments for the course.
With the exception of the CF and MP3 modules, every other aspect of our project was functional by the conclusion of the semester. Given more time and another PCB, we strongly believe that the project would see total completion. Now armed with a semester’s experience, locating errors in the layout prior to fabrication would be much easier.
The lessons garnered from the semester’s experiences have prepared the members of this team well for the workplace. We have learned that engineering is as much about formulas as it is about having fun. Had we not taken the time to enjoy portions of the design process, we would not have achieved as much as we did. This will undoubtedly carry over into the professional world and the rest of our lives.
References
Design Constraint Analysis
Ultimode SCM220 Starter Kit
1.
Rabbit 3000 Microprocessor
2.
LCD Display by
3.
Crystalfontz CFAG12864B-TMI-V
4.
ST STA013 MPEG Decoder
5.
Micronas MAS 3507D MPEG Decoder
6.
Cirrus Logic CS4334 D/A Converter
7.
Micronas DAC 3550A
8.
Grayhill Series 25L Mechanical Encoder
9.
Panasonic SSG PNA1401L Phototransistor
10.
Packaging Specifications and Design
BJL-1150
11.
CDJ-1000
12.
Circuit Design and Theory of Operation
Processor
13.
14.
Compact Flash
15.
16.
MP3 Decoder
17.
18.
Rotary Pulse Generator
19. $FILE/E-33-34.pdf
Slide Controller
20.
21.
LCD Display and Keyboard
22.
23.
Power Regulator
24.
Printed Circuit Board Layout Design
Motorola Application Note AN1259
25.
Rabbit Header Spacing
26.
Compact Flash Header Spacing
27.
Patent Liability Analysis
United States Patent Office
28.
Dr. Meyer’s Lecture on Patent Liability
29.
Reliability and Safety Analysis
Linear Converters
30.
31.
MAXIM Level Converter
32.
33.
Rotary Pulse Generator
34.
Rabbit 2000 Microprocessor
35.
Military Handbook: Reliability Prediction of Electronic Equipment
36.
Software Design Considerations, Narrative and Documentation
Sample Rabbit Code
37.
Sample CF Code
38.
CF Theory of Operation
39.
Sample MP3/FAT 32 Code
40.
Ethical and Environmental Impact Analysis
IEEE Code of Ethics
41.
ACM Code of Ethics
42.
Product Testing
43.
Software Engineering Code of Ethics and Professional Practice
44.
Introduction to Watchdogs
45.
CPSC Background Information Electronic Devices
46.
Engineering Education Reform: A Trilogy
47.
Fact Sheet: Printed Circuit Board Manufacturers
48.
E-Waste Laws
49.
Problems with disposal of LC displays
50.
Appendix A: Individual Contributions
Contributions of Clewin:
This is my attempt to summarize sixteen weeks in one page. As the team leader, my job was two fold – monitoring team progress and allocation of responsibility. The team made this job practically unnecessary as everyone was willing to play an integral role in bringing the design to completion and understood the need for teamwork in bringing our project to completion. In addition to being team leader I served as an integral part of the design team and was the backup storage for our notebooks (which mysteriously kept being deleted).
Early in the semester, as a team we brainstormed possible project ideas I was an integral part of this process, as was everyone else. When we had decided on a digital DJ turntable I did some research on similar products as well as some of the components that could be used in our design. I sketched a possible block diagram of the unit and made revisions after discussions and input from the rest of the team. As a team we divided research responsibilities and I looked at possible LCDs and other possible user interface devices (jog dials and pushbuttons).
After the arrival of some of our parts, we started prototyping. I started prototyping the MP3 circuit. I stopped this to work on the schematic and Jim undertook the responsibility of the MP3 section of the unit.
I was responsible for the schematic, which was a very large assignment. It was extremely difficult since we still had many unanswered questions and were considering using the Rabbit processor instead of the SCM 220. I spent a lot of time on this. I assisted Jim in the Layout, making footprints while he routed the traces.
The ethical and environmental analysis was also my responsibility. I did a lot of research to ensure that the safety of the user was taken into account in the design. This assignment helped me understand a lot of the procedures that are necessary in testing a product and some of the environmental issues that are involved in manufacturing a product.
The team worked in parallel to ensure that everyone was involved in every part of the design process. I worked with Nick on the initial CF interface. I worked on prototyping the RPG and wrote the software to gather a velocity vector to be used by the processor for tempo manipulation. I also helped in the early prototyping of the LCD and MP3 decoder and circuit.
I did research and wrote software that would parse the ID3 header for information about the mp3 that would be displayed by the LCD.
While the Nick and Jim were working on debugging the circuit, I worked on the packaging, utilizing the ME machine shop to make our package. I later worked with Ruth on assembling the unit and installing parts into the package.
I also worked on the User Manual and the Final Presentation while we continued to debug and try to get the CF and MP3 circuit to work.
Overall, I believe that I made an important contribution to my team, being involved in every aspect of the design process. Despite not bringing the project to full completion, based on the time and effort spent along with the knowledge gained in this course my teammates and I deserve As (will probably get a B, but deserve an A).
Contributions of Jim:
Looking back on the project I feel like a lot of the problems we encountered were my fault. I was assigned the task of picking which MP3 decoder to use and chose one that was used on numerous other projects. I found a very useful site that had a circuit already built for the decoder as well as a digital to analog converter. We ended up not being able to get it to work. The site is always were we found the LCD we used. It was the biggest we found and also came with pushbuttons with it. Those worked out very well with our final project.
I also did the layout and there was alot of mistakes on that as well. I wish we would have had more time for the 477 Staff to review the layout of the board before sending it to the fab. I think that the design review would be helpful after both the schematic and the layout are done, not just the schematic. Before actually doing the layout, I modified the schematic significantly. I rearranged what went to which pins on the Rabbit. I also separated the CF onto a different board to be cut off later.
I was there most of the time any soldering was done helping Nick with that. I watched John give a demo to someone else on soldering surface mount capacitors. I shared that info with Nick which along with Chucks help made him a soldering master. I straighten all the wires for the two Rabbit header adapters and then also placed them into new sockets. It is not an easy thing to get 40 wires to line up with holes that are barely big enough takes a little bit of time. I attempted some soldering on my own, with little success.
I was responsible for the Reliability and Safety homework. This gave me alot of experience looking at data sheets and through the Military Handbook. I had never done anything like that before. I was exposed to the FMECA briefly in EPICS but did not actually fill one out.
I think I helped with every part of the software expect the CF in some way. I started the LCD program and figured out that we had to bypass the RS232 chip. After looking at the Ultimode processor I had my doubts about it and raise some concern. I even went so far as sampling a PIC processor in cause down the line we needed to switch. The Rabbit was a good choice we just needed to stick with it from the beginning. I wrote the bit bagging serial routine for the ATD and attempted to write it for I2C with less success.
Probably my biggest contribution was figuring out the MP3 and eventually MP2 manipulation. I figured out the frame headers, how to extract them and that MP3 have overlapping information in there frames. I wrote the test Python script to split them and manipulate them. I wish we could have gotten the MP3 decoder to work to try this out in the hardware.
I know a lot of the things that I have done did not work out as planned. Looking back I would have taken more time with the layout and schematic. We worked hard to try to over come the mistakes but they set us back too much. I know I did my best and worked as hard at this class as any in my college career. I just wish I could said it turned out better.
Course Grade: B-
Contributions of Ruth:
This project was made possible through the efforts of all of the team members. The first assignment that each of us had, was to do research into some of the parts. I researched different options for the microprocessor. I looked at some of the Rabbit options and a few of the Atmel options. We decided to use the Rabbit 3000 microprocessor. In working on the Orcad homework assignment, I assisted on some of the schematic and worked on parts of the layout. One of the major things that I worked on was in finding the footprints for some of the parts.
The first homework that I did was the Packaging Design Specifications Homework. For this homework research was done into what materials were available and would work well.
I also did rough drafts of both the Design Review and Final Presentation slides. I also did the formatting for the Final Presentation slides.
Although Jim had primary responsibility for doing the layout homework, I assisted in finding some of the footprints. While he worked on the major components I found footprints for the resistors, capacitors, and a couple of the other small components.
The next homework that I was responsible for was the Patent Liability Analysis Homework. This required many hours of research into different possible patents which our project might infringe upon. Most of the patents that I looked at we did not infringe upon, however understanding the patents well enough to understand whether infringement occurred or not.
One of my biggest contributions to the project was the programming of the LCD. Clewin designed the Splash Screen and the ASCII art of the Main Screen. However I was responsible for adding the arrows and the other menus. I was also responsible for adding the button functionality which enabled the user to move from screen to screen, and scroll up and down in the screen. The buttons sent messages to the microprocessor whenever any of them are pressed or released. These messages are then processed and either the LCD screen is manipulated or signals would be sent to the MP3 decoder. The LCD was also used for debugging some of the other components.
The other main component that I worked on was the Linear Potentiometer and ATD Converter. This was used as a slide tempo control. After some investigation we found that the potentiometer was not linear, so we divided it into nine distinct sections. The middle section was assigned a zero. The sections below it were assigned values from -1 to -4 and the sections above it were assigned values from 1 to 4. These values were then used to decrease or increase the base tempo. (The tempo before the platter was rotated.)
I also did some of the work putting together the User Manual. I also did most of the shopping for items which could be purchased in town. I also used a hacksaw to cut up some of the plywood which was then used to place the platter and RPG inside of the base unit.
This group worked very hard and learned a lot. Because we were unable to finish the entire project and complete all of the success criteria, I do not believe that we really deserve an A. However we did learn perhaps more than we might have if it had been an easier project that had come together easily. Therefore I believe that we have earned at least a B. I feel that we all worked very hard on this project, and therefore all of us deserve a B.
Contributions of Nick:
My contributions to this team’s progress began early when I assumed responsibility for the first and third homework assignments, both of which dealt with the preliminary concepts of our project. Around the same time, I assumed the role of webmaster for the team. I designed the page layout using CSS and HTML. To make notebook updating easier, I also wrote a cgi script in Python. Our notebooks were deleted twice throughout the course of the semester, and after the first deletion, we resorted to just updating them manually (which allowed us to write protect them).
From the design aspect, I was responsible for the initial research on the rotational sensing mechanism to be used in conjunction with the platter. I investigated slide potentiometers and photo transistors, and provided an analysis of both for a team decision. For the design homework, I completed the Design Constraint Analysis (Homework 4). This homework was a culmination of notes taken at group meetings and my own general analysis. For the professional homework, I completed the Software Design Considerations, Narrative, and Documentation (Homework 10). This homework was based primarily on my own analysis and in small part by comments made by other team members. I also assembled the final report.
From the implementation aspect, I was primarily responsible for hardware assembly, the CF module (design and coding), as well as the overall software design for the system. I performed the hardware assembly for the entire PCB, as well as nearly 150 fly-wires as the board was debugged. I designed and constructed custom crossover headers for the mirrored Rabbit footprints. In addition to the crossover headers, I fly-wired a 50 pin CF header, rerouted a number of crossed traces, and built custom headers for peripheral devices. I designed the algorithms for interfacing to the CF card and wrote them in Dynamic C. Though I was never able to prove their functionality (due to problems with the PCB), I did compare my algorithms with those of another team using the same device, and they were similar enough for me to conclude that mine would have worked. My final major responsibility during implementation was overall software design. Since the system never worked completely, some of the framework for the embedded software system could not be proven. Though I am certain that most of it is correct, I must also admit that this system would have required a bit more tweaking before becoming completely functional. Given a functional hardware system, such tweaking would have been trivial.
I spent roughly 175 hours on this project over the course of the semester. Had we been able to rid the PCB of all of its errors, I imagine that that number might have been a bit higher, if for no other reason than to perform full system testing. I feel I was sufficiently committed to this project in all aspects. Our team unfortunately made one fatal error (by not debugging the PCB sooner), and it cost us two success criteria and a fully functional project. I do not feel, however, that failure to realize these two criteria should result in a major grade reduction. We not only learned invaluable lessons, but we also were able to precisely pinpoint the sources of all our errors.
For my contributions to this project, I believe I deserve a low “A.” This grade embodies a penalty for not finishing the project but recognizes the significant strides I personally made in an attempt to complete it.
Appendix B: Packaging
Figure B.1: Top View
Figure B.2: Front View
Figure B.3: Back View
Appendix C: Schematic
Appendix C.2: Bill Of Materials
Group 7: Breakthrough Electronic Audio Turntable System Revised: Thursday, March 11, 2004
Revision: 2.4
Bill Of Materials March 11,2004 15:23:16 Page1
Item Quantity Reference Part
______________________________________________
1 1 C1 100uF
2 4 C2 .1uF
C3 .1uF
C54 .1uF
C55 .1uF
3 2 C22 22pF
C21 22pF
4 2 C26 0.0033uF
C28 0.0033uF
5 10 C29 0.1uF
C30 0.1uF
C31 0.1uF
C32 0.1uF
C33 0.1uF
C35 0.1uF
C38 0.1uF
C44 0.1uF
C48 0.1uF
C51 0.1uF
6 1 C34 470pF
7 1 C36 0.0047uF
8 2 C39 3.3uF
C42 3.3uF
9 1 C43 10uF
10 2 C45 22uF
C50 22uF
11 2 C47 0.22Uf
C46 0.22uF
12 1 J1 RPG
13 2 J3 CON2
J12 CON2
14 1 J4 LCD
15 1 J6 LEFT
16 1 J7 RIGHT
17 1 J9 RABBITD1
18 1 J10 CF
19 1 J11 RESBUTT
20 1 J14 RABBITD2
21 1 J15 RABBIT2
22 1 J16 RABBIT1
23 2 J23 CF HEADER
J22 CF HEADER
24 2 R1 100k
R9 100k
25 2 R4 270k
R2 270k
26 2 R5 560
R3 560
27 2 R6 4.7
R7 4.7
28 1 R8 1k
29 1 R10 1M
30 2 R16 10k
R11 10k
31 1 U4 STA013
32 1 U5 TLC548C
33 1 U6 CS4334
34 1 U7 MAX3002
35 2 U11 LM340/SM
U12 LM340/SM
36 1 U13 LM2936/TO
37 1 Y1 14.7645MHz
Appendix C.3: Design Rule Check
Checking Pins and Pin Connections
--------------------------------------------------
Checking Schematic: SCHEMATIC1
--------------------------------------------------
Checking Electrical Rules
Checking for Unconnected Nets
Checking Off-Page Connections
Checking Pin to Port Connections
Checking for Invalid References
Checking for Duplicate References
Reporting Ports
Reporting Off-Page Connections
Reporting Globals
GND
Reporting Net Names
N146120
N173688
N181819
N46771
N505651
5VOLTSCF
N52228
N204297
N33112
N205049
SDI
FILT
XTI
OCLK
XTO
SCKT
SDO
SCKR
AOUTL
AOUTR
PVDD
LRCKT
SCL
SDA
PVSS
N10010
N36018
VRAM
BD2
BD4
BD6
PE5
DATA1
I2CSDA
DATA2
RES_IN
BIOWR
RESET
VBAT
PB7
PB6
SMODE1
BBUFFEN
CLOCK
BD3
PE2
BD5
BIORD
DATA_REQ
PE3
BD7
WDO
I2CSCL
SMODE0
BD1
PB3
PB1
RDY/!BSY
STATUS
PB5
PB4
BD0
3VOLTS
DO0
DO7
RCV
OE
PC6
AO2
CD1
DO4
BA0
BA8
BA6
PC7
5VOLTS
DO1
BA12
DO3
DO5
WE
DO2
DO6
BA3
BA2
BA11
CE1
PC5
I/OCLK
DDATA
BA1
TRNS
BA4
BA10
AO0
AO1
BA7
BA5
BA9
PCLK
PD3
DATA
Check Bus width mismatch
Appendix D: PCB Layout Top and Bottom Copper
The problems with the layout included 2 crosses of traces, 2 pins on the ATD not connected, the CF header being wrong, and the Rabbit header being flipped.
Appendix E: Parts List Spreadsheet
A copy of the parts list spreadsheet should be included here.
Appendix F: Software Listing
A copy of the final software code listing(s) should be included here, printed in a small (10 point) CONSTANT WIDTH FONT.
Appendix G: User Manual
ECE 477 – Digital Systems Senior Design Project
Team mixMaster
BREAKTHROUGH .ELECTRONIC.AUDIO TURNTABLE SYSTEM
b.e.a.t.s
User Manual
à TEAM MIXMASTER
Electrical Engineering Building • Lab 61
Purdue University •West Lafayette •IN 47907
Phone 1-800-MIX-MSTR
Table of Contents
Chapter 1
Introduction G-4
Chapter 2
Safety Information G-5
Important Information G-6
Chapter 3
B.E.A.T.S. Diagram & Parts Description G-7
Chapter 4
Setup G-9
Basic Use G-10
Advanced Use G-12
Chapter 5
Trouble Shooting G-13
Warranty G-14
Support Information G-15
Congratulations
hank you for your confidence in Team mixMasters. You’ve selected one of the best-built products available today, and we will do everything in our power to keep you happy with your purchase for many years to come.
The Breakthrough Electronic Audio Turntable System (B.EA.T.S.) is the ultimate tool for today’s skilled turntablist and even for the novice that is attempting to break into the industry. This unit was designed with DJs in mind to give the user absolute control over the mp2.
The device status and user interface will be displayed on a LCD, along with the title, artist, length and elapsed time of the song.
The mp2 is loaded from a compact flash card, and a high-torque platter allows the user to manipulate the mp2 in the same manner that would be done on a vinyl player. Further manipulation of the file is performed via buttons that will enable the user to set and execute loops and cueing, and a slide that enables tempo control.
For best use, please read this entire manual before connecting and using this unit.
Features
Safety Information
[pic]
[pic]
Important Information
For optimum performance:
1. These safety and operating instructions should be kept for future reference.
2. Only connect to a power supply such as the one specified in the operating instructions.
3. Always make sure that AC power is OFF while making any connections.
4. Power supply cords should be routed so that they are not likely to be stepped on or pinched.
5. When removing the power supply from an outlet, remove it by holding the plug attachment and not by pulling on the cord.
6. Turn off and unplug the unit when it is not in use.
7. To avoid electric shock, do not open the unit when it is plugged in.
8. Never attempt to make any adjustments or repairs yourself. If problems occur with the unit, contact Team mixMaster customer support.
9. Do not place the unit in a location where it will be exposed to direct sunlight or near a heating appliance.
10. Do not place the unit in a location where there is high humidity or a lot of dust.
11. Take precautions to ensure that liquids and other objects do not fall into the inside.
12. Place unit on a stable location that has no vibration.
13. When cleaning, use a soft cloth to wipe down the outside of the unit. Never use volatile cleaners such as benzene, solvent or thinner.
14. Never use spray cleaners or oils on the slide control. Residues cause excessive dirt buildup
B.E.A.T.S Diagram &
Parts Description
1. Platter This platter connects directly to an rpg. The platter serves as the interface for jogging and pitch
modulation.
2. Tempo Adjust Slider Changes playback tempo between ± 50 %.
3. LCD Display Displays information regarding the unit.
4. Button Interface See 6 – 17 for details.
5. CF Slot The slot for the CF Card.
6. CUE SET To set a cue point in the file.
7.
8. PLAY / PAUSE To start and pause playback.
9. STOP To stop playback.
10. REW To fast reverse playback.
11. FFWD To fast forward playback.
12. LOOP START / STOP Calls the cue points stored in internal memory. To
start the loop that has been set. Press again to
stop the loop.
13. UP To scroll up a list.
14.
15. RIGHT To go forward in a menu.
16. DOWN To scroll down a list.
17. LEFT To go back to the previous menu screen
18. AUDIO (L & R) The phono jack for audio output (Left and Right).
19. POWER IN The power cord output slot.
20. POWER ON / OFF A pushbutton. The turn ON beats, press in, to turn
OFF, depress.
Setup
Before making or changing the connections, switch off the power and disconnect the power cord from the AC outlet.
1. Connecting to a DJ mixer, or stereo amplifier
Use the supplied audio cables and connect the white plug to the left (L) terminal and the red plug to the right (R) terminal on the back of B.EA.T.S. and the mixer or stereo amplifier.
[pic]
2. Connecting the power cord
When the above connection has been made, connect the power plug to an AC wall outlet.
3. Turning the Unit On
After ensuring that the unit is properly plugged in, press the power button on the front panel in. To turn it off, press it again. The screen below will be displayed on successful startup.
Basic Use
Loading CompactFlash Card
Insert the CF card into the reader and gently depress until the card cannot go further in.
Changing Screens
From the main screen three different menus can be accessed. First use the up and down arrows until the menu you wish to view is highlighted. Use the right arrow button to change into that menu. To go to the previous screen, press the left arrow button.
Selecting a Song
From the main, menu, select the option to load a song. Once the option is selected, scroll through the list until the song is identified by the title and artist name scrolling. Press the right button to load the song.
Starting Playback
Once a song has been loaded into memory, press the PLAY / PAUSE button.
Stopping Playback
During playback, press the STOP button. The player will stop playing the song that is was playing. It will return to the beginning of the song.
To Pause Playback
During playback, press the PLAY / PAUSE button. The player will then pause on the song that it is currently playing. To resume play at the same location, press the PLAY/PAUSE button again.
Fast-Forward / Fast-Reverse
Once a song is loaded and being player, press and hold the FFWD button to fast forward through the song; press and hold the REW button to fast reverse through the song.
Advanced Use
Scratch Play
While a song is playing, rotating the platter will cause the song to change tempo. Rotating it in a clockwise direction will speed the song up. Rotating it in a counter clockwise direction will cause it to reverse. As soon as the platter is no longer rotating, normal play will resume.
Changing Playback Speed
Move the slide towards you (-) to decrease the tempo and move it away from you (+) to increase it. The rate of change is shown next to the slide.
Loop Playback
During playback, press the CUE SET button at the point where you want the loop to commence. Press the CUE SET again at the point which you wish the loop to end. To execute the loop, press the LOOP START / STOP button. To stop the loop, press the LOOP START / STOP button.
Troubleshooting
The turntable has no power:
1. Check if the power cord is connected and plugged in.
2. Is the power button in the “ON” position
There is no sound:
1. Make sure that the audio out (L & R) are connected to speaker.
2. Ensure that a file has been loaded into memory.
The sound is noisy or distorted:
1. If the unit too close to a television or other similar appliances move it away or turn the appliance off.
I cannot play audio:
1. Ensure that the CF is inserted correctly and that a song is loaded into memory.
My sound is skipping:
1. Ensure that the unit is on a stable surface to avoid vibration or shock.
2. Ensure that your mp2 is seamless and that the CF card is not damaged.
My sound is low:
1. Connect the unit’s audio output to a device with phono preamp.
When “cue” is in use, track search does not finish:
1. Ensure that the cue point has been set
Pressing “loop start/stop” does not start loop play:
1. Ensure that the cue points have been set.
Warranty
Team mixMaster warrants the original purchaser that B.E.A.T.S. is free from defects in material and workmanship under normal use and service for the period commencing from the purchase from an authorized dealer and continuing for 2 years from that date.
The warranty does not cover defects or damage from accident, misuse, abuse, neglect, unusual physical or electrical issues or modification by the purchaser or any other service person, not authorized by Team mixMaster.
Support Information
Team mixMaster provides a toll free customer support line to provide set up help and to answer any questions, should you encounter any problems when using B.E.A.T.S. You may also visit us on the web at for any comments or suggestions. For service related issues please contact our customer support. Our service hours are Monday through Friday 9:00 a.m. to 5:00 p.m. Central Time.
Team mixMaster Customer Support
Electrical Engineering Building
Purdue University •West Lafayette •IN 47907
Voice: (800) MIX-MSTR
Email: 477grp7@ecn.purdue.edu
URL: TTT
Appendix H: FMECA Worksheet
Criticality:
Low – Minor functionality lost
Medium – Total functionality lost
High – Possible Injury to user
|Failure No. |Failure Mode |Possible Causes |Failure Effects |Method of Detection |Criticality |Remarks |
|A: Power Supply (Linear Regulators, Capacitors, Wall Wort) |
|A1 |VCC = 0V |Any Short, Failure of any part |No power, No operation |Observation |HIGH |Over heating may occur |
|A2 |VCC_5 > 5V |Failure of Linear Regulators |Damages parts, overheating |Observation |HIGH | |
|A3 |VCC_3 > 3V |Failure of Linear Regulators |Damages to MP3 decoder |Observation |HIGH | |
|A4 |VCC out of tolerance |Malfunction of any of the parts |Unpredictable performance |Observation |MED | |
|B: User Interface (LCD, Pushbuttons, A/D, Potentiometer, RPG) |
|B1 |Cable / Ribbon Disconnect |Too sudden of movement |Loss of control / feedback |Internal Observation |LOW |Better / More secure |
| | | | | | |connections |
|B2 |LCD Not working |Physically Damaged, disconnected,|No display |Observation |MED | |
| | |Software Error | | | | |
|B3 |Pushbutton Not working |Software Error, Buttons |Loss of Control |Observation |MED | |
| | |damages/stuck, disconnected | | | | |
|Failure No. |Failure Mode |Possible Causes |Failure Effects |Method of Detection |Criticality |Remarks |
|B4 |No Tempo Change |Software Error, disconnected, |No Tempo Change |Observation |LOW | |
| | |damaged parts | | | | |
|B5 |Incorrect Tempo Change |Software Error |Incorrect Tempo Change |Observation |LOW | |
|C: CF Board (CF Header, IDE Cable) |
|C1 |CF Card won't go in |Bent Pins, something in the slot |Unable to load songs |Observation |MED | |
| | |already | | | | |
|C2 |CF Card can't be read |Bad CF Card, cable disconnect, |Unable to load songs |Observation |MED | |
| | |Software Error | | | | |
|C3 |CF Card Overheat / Damaged |Voltage Regulator failed |Damage Card, Damage CF |Observation |HIGH | |
| | | |Header | | | |
|D: MP3 (MP3 Decoder, D/A, Level Converter, Oscillator) |
|D1 |Bad MP3 Playback |Oscillator Failure, ICs damaged, |Bad MP3 Playback |Observation |MED | |
| | |Bad connection | | | | |
|D2 |Skipping MP3s |Software Error, Oscillator |Skipping MP3s |Observation |LOW | |
| | |Failure | | | | |
|Failure No. |Failure Mode |Possible Causes |Failure Effects |Method of Detection |Criticality |Remarks |
|D3 |Noisy Audio Playback |Bad connections between ICs |Noisy Audio Playback |Observation |LOW | |
|E: Processor (Rabbit 2000) |
|E1 |Random Output |Software Error, Damaged Processor|Loss of Usability |Observation |MED | |
|E2 |All output Zero/One |Damaged Processor |Loss of Usability |Observation |MED | |
|E3 |Won’t except Inputs |Damaged Processor, Disconnected |Loss of Usability |Observation |MED | |
|E4 |Unexpected Output |Damaged Processor |Loss of Usability, Bad Audio|Observation |MED | |
| | | |Output, Random LCD Output | | | |
-----------------------
t
1
|High torque platter |Output for audio (L & R) |
|±25, 30 & 50% tempo adjustment |Button interface |
|LCD display indicating |- play / stop |
|- Play mode |- rew |
|- Song information |- ffwd |
|Removable dust cover |- loop start / stop |
| |- cue point set |
1
Chapter
1
|Abstract |1 |
| 1.0 Project Overview and Block Diagram |? |
| 2.0 Team Success Criteria and Fulfillment |? |
| 3.0 Constraint Analysis and Component Selection |? |
| 4.0 Patent Liability Analysis |? |
| 5.0 Reliability and Safety Analysis |? |
| 6.0 Ethical and Environmental Impact Analysis |? |
| 7.0 Packaging Design Considerations |? |
| 8.0 Schematic Design Considerations |? |
| 9.0 PCB Layout Design Considerations |? |
|10.0 Software Design Considerations |? |
|11.0 Version 2 Changes |? |
|12.0 Summary and Conclusions |? |
|13.0 References |? |
|Appendix A: Individual Contributions |? |
|Appendix B: Packaging |? |
|Appendix C: Schematic |? |
|Appendix D: PCB Layout Top and Bottom Copper |? |
|Appendix E: Parts List Spreadsheet |? |
|Appendix F: Software Listing |? |
|Appendix G: User Manual |? |
|Appendix H: FMECA Worksheet |? |
1
1
1
Chapter
2
!
Chapter
4
!
1
Chapter
5
1
!
7
19
18
20
3
2
1
5
4
File Selection
Anon - Purdue ECE Theme
Nick - Solder Free & Lov
Britney Spears – Toxic
Ruth - Pack Me To Washin
50 Cent - In The Club
Clewin - In The Lab
Jim - I know Who’s Hot
****** MAIN MENU ******
___
/ \ \ -> LOAD A FILE
| O | | CURRENT SONG
\___/ @ HELP!
******B.E.A.T.S.******
***** CURRENT SONG *****
Solder Free & Loving It
Nick Schnettler
Total 2:30 Cue 1:00
Remain 1:30 Loop 2:00
******B.E.A.T.S.******
15
11
10
9
8
7
6
14
13
12
17
16
21”
14.5”
6”
1.75”
4.875”
2.875”
LCD
Buttons
Flash Slot
11”
Platter
Tempo Control
21”
3.5”
1.75”
Power Button
RCA L&R
Power In
21”
3.5”
9.5”
8”
Comments:
Jim Bauerle
Ruth Devlaeminck
Nick Schnettler
Clewin McPherson
Figure D.1.: Copper Top Layout
Figure D.2.: Copper Bottom Layout
BREAKTHROUGH ELECTRONIC
___ ___ ____ __
( _ \( _) /\ (_ _/__)
)_ < ) ) /()\ )( \_ \
(___/(___)(_)(_)(__)(__/
AUDIO TURNTABLE SYSTEM
Top View
Button Interface (4)
Rear View
Front View
Figure C.1.:
P.1 Schematic
Figure C.2.:
P.2 Schematic
1 icon key
1 Valuable information
! Use
: Contact Information
Chapter
3
................
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