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Self-Tuning Musical Chime. Mickey Heynen Beth Lopour Tyler Smith Experimental Engineering (ME 224) Professor Espinosa June 6, 2003. Outline. System Overview Mechanical System Experimental Setup and Procedure Demo Data Results. System Overview. 1. User inputs desired frequency - PowerPoint PPT Presentation
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Self-Tuning Musical ChimeSelf-Tuning Musical Chime
Mickey Heynen
Beth Lopour
Tyler Smith
Experimental Engineering (ME 224)
Professor Espinosa
June 6, 2003
OutlineOutline
• System Overview
• Mechanical System
• Experimental Setup and Procedure
• Demo
• Data
• Results
System OverviewSystem 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
Mechanical SystemMechanical System
1. Chime
2. Reservoir
3. Servomotor / Striker
4. DC motor / Pulley Rod
5. Microphone
1
2
34
5
-- Overview
Mechanical SystemMechanical System -- Specifics
DC Gear Motor
• Operating range: 4.5VDC to 12VDC • No load current: 48mA • No load speed: 44rpm • Current @ Max efficiency : 172mA • Speed @ Max efficiency: 35rpm • Torque with load @ max efficiency: 2.37kg/cm • Gear ratio: 100:1
Mechanical SystemMechanical System -- Specifics
Servomotor
• Voltage:4.8V to 6V • Speed: .16 sec/60 degrees• Torque: 49 oz-in (3.57kg/cm) 6 volt
Experimental Setup and ProcedureExperimental Setup and Procedure
Experimental Setup and ProcedureExperimental Setup and Procedure
DemoDemo
DataData -- Correct frequency detected?
Calculated output frequency: 616 HzActual output frequency: 614.786 Hz
1000 1200 1400 1600 1800 2000
Data point #
DataData -- Accurate tuning?
Target Frequency vs. Actual Frequency
585
590
595
600
605
610
615
620
1 2 3 4 5 6 7 8 9 10
Attempt #
Fre
qu
ency
(H
z)
Actual Frequency Target Frequency
-- Efficient tuning?DataData
Target Frequency vs. Actual Frequency
590
595
600
605
610
615
620
1 2 3 4
Attempt #
Fre
qu
en
cy
(H
z)
Actual Frequency Target Frequency
ResultsResults
• 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
-- The Good News
ResultsResults -- 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
SummarySummary
• 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
• 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
Possible ModificationsPossible Modifications
QuestionsQuestions
??