1. Automatic Guitar Tuner TRENTON AHRENS, ALEX CAPO, ERNESTO WONG GROUP 1

2. Goals Design a guitar that will automatically tune to a selected tuning preference Interact with an android application Gain necessary skills required to succeed in the engineering field

3. Motivation Tuning can be time consuming Difficult without extra equipment especially for beginners The interest in music

4. Specifications Tune within 30 seconds Within a noticeable difference of +/- 5 cents (100 cents/semitone) Small profile 5 tuning preferences At least 50 cycles per battery charge Operate outside with moderate humidity

5. 4-String Bass

6. Overall System Block Diagram

7. Division of Labor Ernesto Android app development Code for tuning algorithm Trenton Signal Processing Pickups Mounting Alex Power supply Mounting Code for tuning algorithm

8. Mobile Application User Interface Android Platform Version 4.4.X+ Android Studio Java Bluetooth communication with microcontroller

9. Android Studio

10. Bluetooth Communication Built in Bluetooth capabilities on phone HC-05 Bluetooth module

11. Microcontroller ATMega328p chip 6 analog inputs 10-Bit ADC 6 PWM outputs 20 MHz operating freq.

12. Pickups Magnetic field seen by the pickups will induce an analog voltage that will be read by the ADC inputs Polyphonic Extracted from a Power Gig controller

13. Analog-Digital Conversion Threshold crossing Fast Fourier Transform StringNoteFrequency (Hz) 1 (thinnest)G98 2D73.42 3A55 4 (thickest)E41.2 Standard Tuning For a 4 String Bass Guitar

14. DC Offset & Amplification Guitar signal from pickups is about 20mV-40mV ADC 0-5V

15. Tuning Mechanism Atmega328P controls the tuning algorithm Reflective sensors to determine number of turns H-Bridge for bi-directional rotation QTR-1RC Reflective Sensor (Pololu) L293DNE Dual H-Bridge (Texas Instruments)

16. Motor Mounting Bracket

17. Power Battery Power – NiMH (Nickel Metal Hydride) rechargeable batteries 6xAA battery holster (Adafruit) = 7.2 V 2500 mAh

18. Components to be Powered Atmega328P (Amazon) 1.8-5V Operating voltage 0.2mA current draw while active 4x ROB-12472 Standard Gear Motor (Sparkfun) 3-12V operating voltage 95mA current draw @ 12 V 4xMotor(95mA) + Atmega328P(0.2mA) = 380.2mA 2500mAh/380.2mA = 6.57 hours battery life 2500mAh/95.2mA = 26.26 hours battery life (realistically)

19. Component Decisions 6-String Electric Guitar vs. 4-String Bass Guitar Polyphonic vs. Single Coil ATmega328p Gearmotor vs. Stepper vs. Servo NiMH vs. Li ion IC H-Bridge vs. DIY H-Bridge Android > Apple

20. Difficulties Mounting of motors Emulating the code Reading signals

21. Budget PartCost 4-String Bass Guitar$0 Pickups$20.50 4x Gear motors ROB-12472$ 119.96 Arduino Uno$25.75 HC-05 Bluetooth module$8.40 Shaft couplers & motor mounts$46.00 4x Sensors (QTR-1RC)$12.45 2x H-Bridge (L293DNE)$14.49 Total: $247.55 Funding provided by Boeing : $200

22. Progress

23. Future Plans 1. Design adequate motor mount 2. Signal processing/motor tuning algorithm implementation 3. Finish and test Android application functionality 4.Design and order PCB 5.Combine all subsystems into final product and test

24. Questions?