school of mechanical engineering project number 180: design and build of a self tuning stringed...
DESCRIPTION
Design Specifications Lightweight Keep structural integrity Keep existing manual tuning Remain tuned without power supplied to system Quick and Accurate Cheap (less than $1500) Retain existing size and shapeTRANSCRIPT
School of Mechanical Engineering
Project number 180:Design and Build of a self
tuning stringed instrument
Andrew Leonard Colin Love
Project Outline
• Based around conventional 6 stringed electric guitar
Consists of 3 main components• Data acquisition• Control system • Mechanical tensioning system
Design Specifications
• Lightweight• Keep structural integrity• Keep existing manual tuning• Remain tuned without power supplied to system• Quick and Accurate• Cheap (less than $1500)• Retain existing size and shape
Existing Designs
Transperformance– Price >$4500– Alternate tunings– Open loop / Closed loop control
© Transperformance 2004 www.transperformance.com
Rochester Institute of Technology– Student group to design self tuning guitar– Utilised a FFT algorithm– Incremental control– Extremely unreliable
Existing Designs
Our Solution
• Completely internal• Used for fine tuning• Levers to adjust tension• P- control
Data Acquisition system
Midi Pickup
Each signal generated in separate coils
Conventional Pickup
All signals combined in one coil
Micro
Micro
Micro
Micro
Control system
• Pulsed information from signal refining circuit
• Used 6 PICs; one for each string– Existing knowledge base– Cheap– Easy to program
Control Algorithm
T1 T2
•Time between consecutive rising edges measured
•Valid signals are stored in an array
•Motors activated when 8 consecutive valid signals are received
•Predefined set-point
•Last 8 set-point errors averaged and P-control utilised
Motor Control
Speed controlled by pulse width modulation
Micro
PWM
Direction
Motor Driver
DC Motor
Mechanical System
In-body Design– Motors with low speed/high torque gearboxes– Threaded rod – linkage – lever
How it works
Questions?
