October 13, 2000 - School of Engineering Science
Contents
1. 2000 Perfect Pitch Instruments 4 Push buttons Programmable User Interface Figure 3 Required elements for the Programmable User Interface Tuning Range The user shall be initially required to adjust each string within a tolerance of one semitone using the tuning pegs at the head of the guitar At this time the user shall wish to adjust the initial orientation of the fine tuning mechanism in order to allow maximum fine tuning adjustability in both directions After numerous automatic tunings several strings may find that their fine tuners are approaching their adjustability limit in one direction This will be especially evident with the higher strings At this time the user shall be required to manually tune the guitar at the head and re adjust the orientation of the fine tuners This is consistent with manual fine tuning systems commonly available on the market The total tuning ranges for the fine tuners shall vary from approximately 2 semitones for the high E string to 4 5 semitones for the low E string Self Training A simple user s manual shall accompany the automatic guitar tuner outlining the steps to implement the tuning process With these step by step instructions the user should be able to train themselves The manual must include how to string the guitar how to connect the power source to the system how to power up the system how to program the user interface how to initiate the tuning process h2. 2000 Perfect Pitch Instruments 1 The entire mechanism as a finished product will be encased in a plastic shell to protect the user from the electronic components also ensuring that the playability of the guitar is not hindered Standards The tuning system will adhere to IEEE standards and will be compared to the accuracy of hand held electronic tuners Reliability Requirements The guitar tuner shall meet the following reliability requirements Accuracy The tuner shall adjust the string frequency within a steady state error to be later determined experimentally A psycho acoustic experiment shall be conducted in which the Just Noticeable Difference JND is measured for several subjects The system control parameters shall be adjusted in order to achieve a steady state error below the measured JND Durability The device shall be sufficiently robust to withstand daily use at an average of one tuning per day for a minimum of 2 years The device after being embedded in the guitar body shall be able to withstand the impact of a 3 meter drop Potential System Limitations The guitar tuner shall be limited by the following factors e The electromechanical system must be small enough to fit inside the guitar body It also cannot be obtrusive to the musician by extruding too far out of the body e The tuner cannot make a significant weight difference when installed in the guitar e The power required to operate the device should
3. and mechanical characteristics The user interface is described in detail along with any other information that will be of use to the guitar player 1 e user manual training etc With these functional parameters we hope that our system will be much appreciated in the guitar world Rock on 2000 Perfect Pitch Instruments
4. be minimized Since the electric guitar is a passive device the tuner will require its own power supply e The strings must be close to their desired frequencies before fine tuning e Only standard string gauges are supported 2000 Perfect Pitch Instruments 8 Test Procedure The following test procedure will verify that the system meets the specifications listed in this document Both normal and error mode testing will be preformed During each test the User Interface will also be tested for its required operation Normal Operation These tests should result in a string frequency within the allowable limits e Fach string will be set to its standard tuning plus a semitone test the time required for tuning and accuracy of the resulting string frequency e Repeat for standard tuning minus a semitone Error Testing Each of the following tests should not affect the function of the tuner or should result in the appropriate error message being displayed to the user Tune a string that is more than a semitone out of tune One or more strings other than the desired string will be plucked at the same time Guitar is instructed to tune but no string is plucked Operation when a bridge fine tuner reaches its tuning limit Conclusion This document introduces the various functional components of the automatic guitar tuner and outlines the product s various operating requirements Also included are the system s physical electrical
5. or if necessary an informative error message to the user as to why no action can be taken in the tuning process 2000 Perfect Pitch Instruments Electrical Requirements The system shall operate with a standard 120V AC wall socket power supply Mechanical Requirements The mechanical assembly entails 6 miniature motors a motor driver system a Floyd Rose Patented fine tuning bridge and a small amount of drive gears and or belts The mechanical assembly shall increase the total weight of the guitar by no more than 10 The mechanical response time shall be made as small as possible Physical Requirements The automatic guitar tuner as a whole will be embedded into the body of the guitar at the time of manufacture The system will be discrete and not interfere with the user The physical requirements are outlined in Table 1 Table 1 System Physical Requirements Environmental Requirements The system will meet environmental requirements detailed in Table 2 Table 2 System Environmental Requirements Operating Temperature 20C to 60C Minimal uW range Over guitar string humidity range Speed The automatic guitar tuning mechanism will tune each string under 10 seconds Safety The tuning system will detect if a string is overly tightened and at risk of snapping and potentially injuring the user At this point an error message will be given to the user and the mechanical actuators will cease to function
6. Perfect Pitch Instruments School of Engineering Science Burnaby BC V5A 1S6 ensc340 pp sfu ca October 13 2000 Dr Andrew Rawicz School of Engineering Science Burnaby British Columbia V5A 1S6 Re ENSC 340 Functional Specifications for an Automatic Guitar Tuner Dear Dr Rawicz The attached document Functional Specifications for an Automatic Guitar Tuner outlines the requirements of our project for ENSC 340 Transducers and Embedded Systems Our goal is to design and develop an automatic guitar tuner that will mechanically tune a guitar as quickly as possible This document highlights the desired functionality of the entire system and the specifications of the various components within the system The functional components include the sensor input processing unit the mechanical actuating unit and the programmable user interface unit Perfect Pitch Instruments was established by five sharp creative and talented engineering science students including Gina Millar Maria Trinh Aaron Schellenberg Terrence Yu and Reva Vaze Should you have any questions or concerns regarding our proposal please feel free to contact me at 604 584 8926 or via email Sincerely Maria Trinh CEO Perfect Pitch Instruments Enclosure Functional Specifications for an Automatic Guitar Tuner Perfect Pitch Instruments Functional Specifications for an Automatic Guitar Tuner Project team Contact personnel Submitted to D
7. ate Gina Millar Aaron Schellenberg Maria Trinh Reva Vaze Terrence Yu Maria Trinh ttrinha sfu ca Dr Andrew Rawicz Steve Whitmore School of Engineering Science Simon Fraser University October 13 2000 Executive Summary Many students become discouraged or are turned away from learning how to play the guitar at the early stages when they realize that they cannot grasp a sense of pitch right away Electronic tuners and pitch pipes exist to help guitar tuning but they are a hassle and are sometimes an embarrassment to use when performing in front of others A guitar player can have an automatic tuning device installed into their existing guitar but often for a price that is greater than the guitar itself This document describes the functional specifications of an accessory that will be capable of tuning a guitar quickly and automatically and would be installed in a guitar at the time of manufacture It would be suitable for all skill levels ranging from beginner to professional because it could help to ease the learning curve for a novice guitarist or provide a performer on stage with a quick and effective means for tuning their guitar between songs to whatever settings they desire Better yet the price of a guitar with this device installed would only cost a fraction more than a guitar without the tuning mechanism This document introduces the various functional components of this automatic tuning system outlining the prod
8. d of three main modules 1 the programmable user interface unit 2 the sensor input processing unit 3 the mechanical actuating unit Each module is specified in the following pages 2000 Perfect Pitch Instruments Programmable User Interface Due to the nature of our project the user interface shall be made as limited as possible so as not to clutter up the body of the guitar The controls that the user shall have at their disposal are the following 1 On Off switch System power button 1 Tune button Toggles between Tune Not Tune modes 3 Small push buttons Used to program system settings 1 LCD display 2 Lines X 16 characters Setting feedback for the user 1 Bi colour LED Indicates tuning status e Green string is tuned within specification e Yellow String is not within specification and needs to be re plucked The user must be able to interface with the automatic tuning system to 1 Program the chord settings to which the tuner will set each string 2 Tell the system when to start tuning 3 If necessary abort the tuning process Of course the user must also pluck the strings to the give the system an input signal In return the system itself must let the user know 1 The system status whether is it in the tuning process or not etc 2 When each string has been successfully tuned 3 If when an error has occurred and what to do about it Essentially once the strings are installed and man
9. en Normally only one pluck of the string is required of the user to tune a given string If however the string has not been given a sufficient amount of time to tune itself the LED shall remain yellow indicating that the user must re pluck the string The user shall successively tune each string while monitoring the color of the LED Once a green light is given for all strings the user may either toggle out of the Tune mode or simply switch the power button to OFF power down the system while keeping the guitar in tune While in the Tune mode anytime the system detects that a certain string is being over tensioned the system shall automatically exit the Tune mode and inform the user via the LCD display that an error has occurred and direct the user if possible to a corrective action Possible causes of an over tensioned string are improper string selection only standard string gauges are supported improper tune settings incorrect initial orientation of the fine tuning mechanism the user shall be required to position the fine tuners so that they allow roughly equal adjustment ranges in both directions or a system malfunction The user system interaction and interface are summarized in Figure 2 amp Figure 3 Choose chord settings Start system tuning Pluck String Automatic Guitar Tuning System System Status Success or Error Msg Programmable User Interface Figure 2 User System interaction
10. ner to professional The tuner can help to ease the learning curve for a novice guitarist or provide a performer on stage with a quick and effective means for tuning their guitar between songs to whatever settings they desire This document outlines the functional specifications of this product including the requirements of the sensor input processing unit the mechanical actuating unit and the programmable user interface unit In doing so this document also resolves Perfect Pitch Instrument s December 2000 deliverables 2000 Perfect Pitch Instruments l system Overview The Process Overview is diagrammed in Figure Essentially the user all but has to pluck the strings on the guitar and the tuning is done automatically The sounding audio frequencies are conditioned and processed electronically and are subsequently provided as inputs to a control module After comparing the pitch of the strings to their desired pitch the control module adjusts the tension in the strings electro mechanically by way of motors gears solenoids etc The entire process is implemented in a feedback loop so that the input to the actuators is adjusted dynamically while tracking the pitch of the string The process completes once the strings are tuned to their desired frequencies Then it is time to rock Pluck String Process Audio Is String in Rock It Tune Automatically Adjust Tuning Figure 1 System Block Diagram The entire system is compose
11. ow to abort the process if necessary how to handle any errors in the system how to turn off the tuning functionality ot a i 2000 Perfect Pitch Instruments 5 sensor input processing Signal Acquisition Extra equipment to acquire the signal generated by the guitar would be redundant since the pick ups of an electric guitar are already tailor made to accomplish the task As seen in the analog signal produced by the guitar s pick ups shall be fed directly to our signal conditioning stage Input from vibrating Output to signal guitar strings conditioning D Guitar Pick ups An Figure 4 Block diagram of signal acquisition Signal Conditioning After being acquired from the guitar pick ups the signal is ready for signal conditioning once it passes the amplitude threshold detection circuitry Signal conditioning is composed of two steps amplification and filtering 3 Output to ut from signal p inp a Actuation system acquisition Poe TE Detector Figure 5 Block diagram for signal conditioning Threshold detection allows definite string vibrations to be processed and ignores faint disturbances Amplification is necessary to amplify the signal to a level that is useful Filtering is crucial to isolating the vibrations of a single string cleaning out any external noise pollution in the signal Signal Output The output of the automatic tuning system is a signal to the actuators to either tighten or loosen the strings
12. ually tuned at the head of the guitar within a tolerance of one semitone of the desired pitch the automatic fine tuning system will take over at the base of the guitar and precisely adjust each string within a very small tolerance to be determined experimentally see Reliability Requirements The user shall program the desired setting for each string into the system before entering the Tune mode The default setting shall be the standard 6 string guitar tuning E A D GBE Once the desired string settings are programmed into the system the user shall toggle the mode button to the Tune mode The self tuning system is now ready to tune the guitar and waits for a plucked string by the user A threshold detection module shall be used by the system to distinguish user input from residual noise induced in the pickups perhaps by movements of the guitar The user shall be required to pluck the string with a moderately firm stroke in order to activate the system which automatically detects and adjusts the tension in the string being plucked The system shall not respond if pluralities of strings are plucked simultaneously The system also assumes that the user is not fretting any of the strings 2000 Perfect Pitch Instruments 3 Once the system detects the string being plucked the LED shall illuminate yellow to indicate that the string is in the process of being tuned A tuned string shall cause the LED to change from yellow to gre
13. uct s different operating requirements 2000 Perfect Pitch Instruments 1 Table of Contents Executive Summar 2000 Perfect Pitch Instruments 1i List of Figures Figure 1 System Block Diagram Figure 2 User System interactio 2000 Perfect Pitch Instruments 11 Introduction Very few people have perfect pitch the ability to identify a note on the musical scale without having any reference note for comparison Although the scientific and psychological aspects of perfect pitch are not well known one thing is certain whether perfect pitch is an inborn talent or an acquired trait 1t need not be an essential or prerequisite for a musician The goal of our project is to design and develop an automatic electric guitar tuner that would eliminate the hassle involved with tuning a guitar manually Although tuners exist in the marketplace today many are handheld requiring the user to pluck a string with one hand hold the tuner with another hand and adjust the tension in the strings with another Clearly too many hands are needed and the tuning process is unnecessarily time consuming The few existing automatic guitar tuners cost thousands of dollars and prove unaffordable for the general public We envision an automatic guitar tuner that would be installed in a guitar at the time of manufacture This accessory will be capable of tuning a guitar automatically and would be suitable for all skill levels ranging from begin
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