Automated Guitar String Tuner BOOM BOOM SSSSSSSSS! Advisor Dr. Robert “Rattler” Albright Industry Representative Mr. Howard “Hooknose” Voorheis, John Fluke Mfg. Authors Ken “Kobra” Aramaki Kevin “Kopperhead” Atebara Petra “Python” Carlson Kevin “Kottonmouth” Vitayaudom Founder’s Day, 2006 University of Portland School of Engineering

Overview Introduction Kopperhead Methods Python/Kottonmouth Results Kobra Conclusion Kobra Demonstration Snake Founder’s Day, 2006 University of Portland School of Engineering

Introduction Project Problem Project Importance Presentation Outcome THANKS- Dr. Albright, Mr. Voorheis, Rick Severs, Sandy Ressel, Dr. Hoffbeck, Dr. Osterberg, Dr. Lu, Dr. Chamberlain, Matt Phelan & Ian Stokes (mechanical consultant) Project Problem-Using a closed-loop control system, tune a guitar string to a specified frequency Project Importance-A true capstone to EE education. Incorporates electrical circuits, electronic circuits, automatic control systems, research Presentation Outcome-Greater understanding of what a control system is, our project, and the accomplishments reached over the year Founder’s Day, 2006 University of Portland School of Engineering

Methods Research Initial Designs Block Diagram Founder’s Day, 2006 More than half the project was research, calculations, simulations System Modeling find/research transfer functions SIMULINK, bode plots, root locus plots, ruth-hurwitz Build and test individual sub-circuits Integrate circuits Test entire system Founder’s Day, 2006 University of Portland School of Engineering

Block Diagram Founder’s Day, 2006 This is the main circuit. Our subtractor opamp takes in two signals, one from the guitar and the other being the reference voltage. The difference of those two voltages is either positive or negative depending on if the frequency of the guitar is higher or lower than the desired frequency. That difference voltage is what moves our motor. The motor turns the guitar peg in this stage. The second part is the feedback loop. The low-pass filter, shown here, eliminates the harmonics, leaving the fundamental frequency. This frequency is then converted into a voltage. The final thing we created was the enable circuit. It ensures that the motor does not turn when the string is not being plucked. When there is a signal from the guitar, the two voltages are allowed to pass through to the subtractor. Founder’s Day, 2006 University of Portland School of Engineering

Methods Cont’d System Modeling Sub-circuits Integration Testing Transfer Function MATLAB & SIMULINK simulations Sub-circuits Built/tested each circuit separately Integration Testing More than half the project was research, calculations, simulations System Modeling find/research transfer functions SIMULINK, bode plots, root locus plots, ruth-hurwitz Build and test individual sub-circuits Integrate circuits Test entire system Founder’s Day, 2006 University of Portland School of Engineering

Results Final Prototype Accuracy Limitations Improvements -Simulation results which were created from our resulting transfer function derived from our block diagram. Those three things: our block diagram, transfer function, and simulations were our research results. After we verified that our system was stable we built and tested our device to obtain our finished prototype. Now we’ll look into the block diagram… -Simulated using MATLAB, we had a very stable system -Systematically built and tested each individual circuit and integrated Founder’s Day, 2006 University of Portland School of Engineering

Conclusion Introduction Project Explanation Design Details/Results Founder’s Day, 2006 University of Portland School of Engineering

Demonstration Founder’s Day, 2006 University of Portland School of Engineering

QuesSsSstionsS? Founder’s Day, 2006 University of Portland School of Engineering