1 Electrical and Computer Engineering Guitar Virtuos Justin D’Alessando (EE) Jacob Dionne (CSE) Adam Montalbano (CSE) Jeffrey Newton (EE) Team Kelly Comprehensive Design Review (CDR)

2 Electrical and Computer Engineering Design Progress  CDR goals reached: Hardware button interface for two strings complete Microcontroller programmed Basic GUI functional paired with song bank New vibration sensing solution  Future goals: USB interface between microcontroller and GUI Finalize logic block and wiring

3 Electrical and Computer Engineering Prototype Completion

4 Electrical and Computer Engineering System Requirements (Revised)  Button Interface: Must not affect playability of guitar Avoid wire clutter  String Detection: Must not affect playability of guitar strings Output voltage produced must be recognized as logic ‘1’  Microcontroller: Accurate logic operation on input from buttons Reliable communication with chosen output interface  Graphical User Interface: Real-time operation Interfacing with microcontroller output efficiently Provide useful results to user

5 Electrical and Computer Engineering Finger Placement Detection  First two strings are fully functional.  Future tasks: Complete the 4 strings which remain. Finalize wiring organization.  Button array and guitar modifications to be completed in coming week.

6 Electrical and Computer Engineering Logic Circuitry  In the past logic operations were done in microcontroller.  Microcontroller can operate up to 16MHz which provides ample sampling rate.  Speed of microcontroller software is a bottleneck.  Hardware will be used to speed up logic operations.

7 Electrical and Computer Engineering Microcontroller to PC Interface  Used MIDI adapter to communicate with PC in past demos.  Desired direct communication via USB port.  Serial communication can be provided using the FTDI USB TTL-232 cable.

8 Electrical and Computer Engineering FTDI USB TTL-232  Orange and yellow pins communicate with microcontroller through its TxD and RxD ports.  Provides convenient 5V Supply and Ground from USB.

9 Electrical and Computer Engineering Guitar Strings Wired to Microcontrollers  2 nd and 4 th String connected to PD2 (Pin16)

10 Electrical and Computer Engineering Voltage Applied to String when Played  Operating voltage of 4.5V to 5.5V for Atmel ATMEGA32 microcontrollers.  Metal pick is powered by 5V power supply.  Each string that is played will have 5V running through it.  6.99E-8 Ohm-m resistivity on the nickel guitar strings which is 12 times more resistive than copper but still very small.  Gloves will be used in near future to prevent shock and a battery holder will be attached to provide portability.

11 Electrical and Computer Engineering Song Bank Design  Note values and timing printed from a text file First three digit string represents the note to be displayed Second three digit string represents the time that the note is to be played (in milliseconds)  Note information is send to GUI to be displayed as song plays Song played using the “sun.audio” library

12 Electrical and Computer Engineering Timing / Beginner Mode  All timing managed by getSleep() method Allows for dynamic timing Every note has a unique timing Shortest note possible is 1ms World record for fastest guitar playing is 20 notes/sec Timing scheme accommodates any song  Beginner Mode allows user to slow down song for easier playing Prototype allows user to play song in half speed Future draft will accommodate slower speeds

13 Electrical and Computer Engineering Graphical User Interface (GUI) Pre-programmed song notes User-played song notes Button Panel Correctly played note Incorrectly played note Fret lines Strings Top Bottom

14 Electrical and Computer Engineering GUI Design Modifications  Re-design of interface allows fretboards to remain stationary Frets drawn onto fretboards Timers used in software to delay notes from being displayed Ovals used to represent notes on the fretboard Solid oval = pinched fret at oval’s location Re-colored string = open note on that string Improves readability of the GUI Allows for simpler software design Results analysis may be an issue How to allow user to see previously misplayed notes? Way to allow user to see upcoming notes?

15 Electrical and Computer Engineering GUI to Song Bank Communication  Song audio is imported and played using the Java Sound API  Songs are then read in line by line from a text file to the GUI software using the Java Scanner class  Note information is extracted within the GUI Each line of the text file is stored in an ArrayList of String objects Switch statements determine note positioning on the fretboards by checking the first character (the guitar string) and then the second and third characters (the fret number) of each entry in the ArrayList Ovals are then drawn at the appropriate position on the fretboard that represents the note, or one of the guitar strings is colored to represent an open note

16 Electrical and Computer Engineering GUI to Song Bank Communication (cont.)  Timing of notes is done using the getSleep() and Thread.sleep() methods getSleep() extracts a delay value (in milliseconds) based on a line from the text file After notes are drawn on the fretboard, Thread.sleep() is invoked with this value to delay following notes from being displayed  This process (aside from the audio portion) repeats until all lines are read from the text file (i.e. – the song has completed)