University of Central Florida Automatic Guitar Tuner Group 1 Trenton Ahrens, Alex Capo, Ernesto Wong 12-4-2014 EEL4919 Fall 2014 Group 1 - Trenton Ahrens, Alex Capo, Ernesto Wong Table of Contents 1 Executive Summary ....................................................................................... 1 2 Project Description ......................................................................................... 2 2.1 Motivation ................................................................................................ 2 2.2 Objectives ................................................................................................ 3 2.2.1 Tuning Time ...................................................................................... 3 2.2.2 Accuracy ........................................................................................... 3 2.2.3 Convenience ..................................................................................... 4 2.2.4 Budget .............................................................................................. 4 2.2.5 Experience ........................................................................................ 4 2.2.6 Knowledge Gain................................................................................ 4 2.3 Project Requirements and Specifications ................................................ 4 2.3.1 Accuracy ........................................................................................... 5 2.3.2 Tuning Preference ............................................................................ 5 2.3.3 Time .................................................................................................. 5 2.3.4 User friendly ...................................................................................... 5 2.3.5 Environment ...................................................................................... 5 2.3.6 Power ................................................................................................ 5 2.3.7 PCB .................................................................................................. 5 3 Research ........................................................................................................ 6 3.1 Relevant Technology ............................................................................... 6 3.1.1 Gibson Min-ETune ............................................................................ 6 3.2 Similar Reference Ideas .......................................................................... 6 3.2.1 "The Mechanix" Guitar Tuner - Cornell University ............................. 7 3.2.2 "Tune Squad" SMARTune - Calvin College ...................................... 7 3.3 4-String Bass Guitar Tuning .................................................................... 7 3.4 Motors ................................................................................................... 10 3.4.1 Servo Motors .................................................................................. 10 3.4.2 Stepper Motors ............................................................................... 11 3.4.3 DC Motor ........................................................................................ 11 3.5 Pickups .................................................................................................. 13 i EEL4919 Fall 2014 Group 1 - Trenton Ahrens, Alex Capo, Ernesto Wong 3.5.1 Magnetic Pickups ............................................................................ 13 3.5.2 Polyphonic Pickups ......................................................................... 14 3.5.3 Piezoelectric Pickups ...................................................................... 14 3.5.4 Humbuckers .................................................................................... 16 3.6 Microcontroller ....................................................................................... 17 3.6.1 Arduino Due .................................................................................... 17 3.6.2 BeagleBone .................................................................................... 17 3.6.3 MSP430 .......................................................................................... 18 3.6.4 PIC Microcontrollers ........................................................................ 18 3.6.5 Atmel AVR ...................................................................................... 19 3.7 Signal Processing .................................................................................. 19 3.7.1 Fast Fourier Transform ................................................................... 19 3.7.2 Wavelet Transform .......................................................................... 20 3.7.3 Goertzel Algorithm .......................................................................... 21 3.7.4 Analog to Digital Converter ............................................................. 22 3.8 Power Source ........................................................................................ 22 3.8.1 Batteries .......................................................................................... 22 3.8.2 Power Supply .................................................................................. 24 3.9 User Interface ........................................................................................ 25 3.9.1 Mobile operating system and application ........................................ 25 3.9.2 Bluetooth Specs .............................................................................. 27 3.9.3 Bluetooth Protocol Stack ................................................................. 30 3.10 Encoders ............................................................................................ 32 3.11 H-Bridge ............................................................................................. 33 4 Hardware and Software Design ................................................................... 35 4.1 Block Diagrams ..................................................................................... 35 4.1.1 Overall System Architecture ........................................................... 35 4.1.2 Power Distribution ........................................................................... 36 4.1.3 Hardware ........................................................................................ 37 4.1.4 Bluetooth Connection ...................................................................... 37 4.1.5 User Interface ................................................................................. 38 ii EEL4919 Fall 2014 Group 1 - Trenton Ahrens, Alex Capo, Ernesto Wong 4.1.6 Microcontroller ................................................................................ 39 4.1.7 Tuning Mechanism (Electrical) ........................................................ 40 4.1.8 Tuning Mechanism (Mechanical) .................................................... 41 4.2 Hardware ............................................................................................... 42 4.2.1 Pickups ........................................................................................... 42 4.2.2 Motor Design .................................................................................. 43 4.2.3 ROB-12472 ..................................................................................... 45 4.2.4 Black & Decker Li2000 .................................................................... 45 4.2.5 Decision .......................................................................................... 46 4.2.6 H-Bridge Design.............................................................................. 46 4.2.7 Encoder Design .............................................................................. 48 4.2.8 Microcontroller ................................................................................ 50 PIC16F1719 ....................................................................................................... 54 4.2.9 Bluetooth Module ............................................................................ 54 4.2.10 PCB ............................................................................................. 56 4.2.11 Mobile Device .............................................................................. 59 4.3 Software ................................................................................................ 59 4.3.1 Mobile Application ........................................................................... 59 4.3.2 Signal Processing Algorithm ........................................................... 61 4.4 Integration of Hardware and Software ................................................... 62 4.4.1 Communication Protocol ................................................................. 62 4.4.2 Microcontroller Programming .......................................................... 64 4.5 Power Design ........................................................................................ 64 4.5.1 Overall Power Circuitry ................................................................... 64 4.5.2 Adafruit 6xAA Battery Pack Holder ................................................. 65 4.5.3 Adafruit 4xAA Battery Pack Holder ................................................. 65 4.5.4 Alkaline 9 Volt Battery ..................................................................... 65 4.5.5 Lithium Ion Polymer Battery ...........................................................