SelfTuning Musical Chime

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Self-Tuning Musical Chime
Mickey Heynen Beth Lopour Tyler
Smith Experimental Engineering (ME
224) Professor Espinosa June 6, 2003
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Outline

• System Overview
• Mechanical System
• Experimental Setup and Procedure
• Demo
• Data
• Results

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System Overview
1. User inputs desired frequency 2. Chime is
struck, and LabVIEW determines frequency of
resulting tone 3. Actual frequency is compared to
target frequency 4. DC motor raises or lowers the
chime 4. Steps 2-4 are repeated until target
frequency is reached 5. Chime is struck again,
sound is recorded
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Mechanical System
-- Overview

• Chime
• Reservoir
• Servomotor / Striker
• DC motor / Pulley Rod
• Microphone

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Mechanical System
-- Specifics

• DC Gear Motor
• Operating range 4.5VDC to 12VDC
• No load current 48mA
• No load speed 44rpm
• Current _at_ Max efficiency 172mA
• Speed _at_ Max efficiency 35rpm
• Torque with load _at_ max efficiency 2.37kg/cm
• Gear ratio 1001

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Mechanical System
-- Specifics

• Servomotor
• Voltage4.8V to 6V
• Speed .16 sec/60 degrees
• Torque 49 oz-in (3.57kg/cm) 6 volt

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Experimental Setup and Procedure
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Experimental Setup and Procedure
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Demo
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Data
-- Correct frequency detected?
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Data
-- Accurate tuning?
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Data
-- Efficient tuning?
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Results
-- The Good News

• Irregularities in waveform do not hinder
  detection
• Tuning tolerance is 1 Hz
• Smaller frequency adjustments as target value is
  reached
• Adjustments are possible in two directions

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Results
-- The Bad News

• Range is very small 585-925 Hz
• Efficiency depends on luck
• System limited by length of chime tone rapidly
  deteriorates when submerged
• If frequency leaves predicted range, crashes or
  endless loops can occur
• User is responsible for emergency stops

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Summary

• Project objectives were accomplished
• Combined familiar and unfamiliar concepts
• - Analog to digital data acquisition
• LabVIEW user interfaces and logic programs
• Methods of signal filtering and processing
• - Use of a microphone as a sensor
• Types of motor control via the DAQ board
• Good foundation many variations are possible

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Possible Modifications

• Multiple chimes for a wider range of pitches
• System records a string of notes and plays them
  back at the end
• The system could play in real-time
• Separate calibration program
• Digital encoder and faster dc motor
• Piano key user interface

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Questions
?