Auto-Chromatic Auto-Chromatic Instrument TunerInstrument Tuner
Erin SmithErin Smith
Advisor: Dr. James IrwinAdvisor: Dr. James Irwin
Date: November 20th, 2000Date: November 20th, 2000
Presentation OverviewPresentation Overview
Project SummaryProject Summary Milestones & Critical ProblemsMilestones & Critical Problems Future WorkFuture Work
Project SummaryProject Summary
Brief Overview of OperationBrief Overview of Operation State of Received TunerState of Received Tuner Proposed ModificationsProposed Modifications
Overview of OperationOverview of Operation
The auto-chromatic tuner is a self The auto-chromatic tuner is a self contained tool that is used to contained tool that is used to determine the pitch and intonation determine the pitch and intonation of a musical instrument in real of a musical instrument in real timetime
Functional DescriptionFunctional Description
InputsInputs– MicrophoneMicrophone– Pitch selectorPitch selector– Power/Mode SwitchPower/Mode Switch
OutputsOutputs– Pitch indicatorPitch indicator– Digital tuning indicatorDigital tuning indicator– SpeakerSpeaker
8031 Microcontroller8031 Microcontroller
E b 6
Auto-Chromatic Tuner
Off
Auto Manual
Tuning
Audible Pitch
G YY RR
LED Display
Pitches:G: Green LED ± 5 centsY: Yellow LED ± 5-15 centsR: Red LED ± 15-50 cents
OctaveUp
PitchUp
Tuning
PitchDown
OctaveDown
Microprocessor
ThresholdDetector
AmplifierMicrophone Timer/Counter
Overflow
Bus
Divide By 2 Tree
Bus
Power/ModeSwitch
Mode
Switched DC Power to all sub-systems
Clock
DC Power
PitchSelector
Bus
Bus
FunctionGenerator
Bus
SpeakerDriver
Speaker Selected Pitch Out
AudioIn
DisplayControlBus Analog Meter
PitchIndicator
PitchIndicator
Tuning LED’s
Automatic Gain Control
FrequencyLook-UpTable
- Parts which do not work, or have not been included yet
Microprocessor
ThresholdDetector
AmplifierMicrophone Timer/Counter
Overflow
Bus
Divide By 2 Tree
Bus
Power/ModeSwitch
Mode
Switched DC Power to all sub-systems
Clock
DC Power
PitchSelector
Bus
Bus
FunctionGenerator
Bus
SpeakerDriver
Speaker Selected Pitch Out
AudioIn
DisplayControlBus Analog Meter
PitchIndicator
PitchIndicator
Tuning LED’s
Automatic Gain Control
FrequencyLook-UpTable
- Parts which were modified
Start
InitializationMode
Read Mode/Power Switch
Auto Tune
Manual Tune Setup and Start Counter
Adjust FrequencyDriver
CounterOverflow
TuningMode
YesRead Counter
Display Results
No
Audible ReferencePitch
Display Pitch
State of Received TunerState of Received Tuner
Auto-tune worked with pre-selected Auto-tune worked with pre-selected octave onlyoctave only
Manual tune supposedly worked, or Manual tune supposedly worked, or had some portion workinghad some portion working
Analog and Digital Tuning workedAnalog and Digital Tuning worked Display worked correctlyDisplay worked correctly Pieces of software worked, but not Pieces of software worked, but not
all in one programall in one program
State of Received TunerState of Received Tuner
Tuner did not work as expected when Tuner did not work as expected when connected to power supplyconnected to power supply
Programmer was faulty, PAL’s were Programmer was faulty, PAL’s were brokenbroken
Unit did not work until mid-MarchUnit did not work until mid-March Analog meter ceased to work (not sure Analog meter ceased to work (not sure
if problem with hardware or software)if problem with hardware or software) No software located for manual tuneNo software located for manual tune
Proposed ModificationsProposed Modifications
Manual Tune completionManual Tune completion Automatic Gain ControlAutomatic Gain Control Expand Digital TuningExpand Digital Tuning Auto-Tune Mode completionAuto-Tune Mode completion
Manual TuneManual Tune
Software for Manual Tune could Software for Manual Tune could not be locatednot be located
Scope was too large, given that no Scope was too large, given that no code was available to work fromcode was available to work from
Due to time constraints, was not Due to time constraints, was not able to complete Manual Tune able to complete Manual Tune modemode
Automatic Gain ControlAutomatic Gain Control
Attempted several different Attempted several different configurations in the Springconfigurations in the Spring– Gain circuit with VaristorGain circuit with Varistor– Circuit with an FETCircuit with an FET
VaristorVaristor
VinVin VoutVout
Gain circuit with Varitstor in parallelGain circuit with Varitstor in parallel
gndgnd
VinVinVoutVout
Low amplitude signalLow amplitude signal
Gain circuit with FET in feedback loop Gain circuit with FET in feedback loop
LPFLPF
Automatic Gain ControlAutomatic Gain Control
Found article with an AGC circuit Found article with an AGC circuit which involves a digital which involves a digital potentiometerpotentiometer
Parts did not come in, so AGC Parts did not come in, so AGC could not be implementedcould not be implemented
CONTROL +
x(t) y(t)
Eref
E(t)_
AGC Circuit which utilizes a Digital Potentiometer
Digital TuningDigital Tuning
Wanted to expand digital tuning from 5 Wanted to expand digital tuning from 5 LED’s to 9 LED’sLED’s to 9 LED’s
Intended to take place of analog meterIntended to take place of analog meter Expanded the truth/logic tablesExpanded the truth/logic tables Not enough memory or bits available to Not enough memory or bits available to
implement the expansionimplement the expansion Required major re-design of hardware Required major re-design of hardware
and doing the wire wrapping over againand doing the wire wrapping over again
test_vectors([A15, A14, A13, A12, A11, A10, A9, A8, A7, WR] -> [dac,pitch]) [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] -> [ 0, 0]; [ 0, 0, 0, 0, 0, 0, 0, 0, 1, 0] -> [ 0, 0]; [ 0, 0, 0, 0, 0, 0, 0, 1, 0, 0] -> [ 0, 0]; [ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0] -> [ 0, 0]; [ 0, 0, 0, 0, 0, 0, 1, 0, 0, 0] -> [ 0, 0]; [ 0, 0, 0, 0, 0, 0, 1, 0, 1, 0] -> [ 0, 0];
([A15, A14, A13, A12, A11, A10, A9, A8, A7, WR] -> [dbt_en]) [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 1] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 0, 0, 1, 0] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 0, 1, 0, 0] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 0, 1, 0, 1] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 0, 1, 1, 0] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 0, 1, 1, 1] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 1, 0, 0, 0] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 1, 0, 0, 1] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 1, 0, 1, 0] -> [ 0]; [ 0, 0, 0, 0, 0, 0, 1, 0, 1, 1] -> [ 0];
Excerpts of Expansion of the Truth Tables Excerpts of Expansion of the Truth Tables (formerly only A15-A11 needed)(formerly only A15-A11 needed)
E b 6
Auto-Chromatic Tuner
Off
Auto Manual
Tuning
Audible Pitch
G BB YY OO RR
LED/LCD Display
Pitches:G: Green LED ± 3 centsB: Blue LED ± 4-10 centsY: Yellow LED ± 11-20 centsO: Orange LED ± 21-30 centsR: Red LED ± 31-50 cents
Octave:Pitch:
Tuning
Auto-Tune ModeAuto-Tune Mode
Worked with pre-selected octave onlyWorked with pre-selected octave only Learned how Timer 0 Overflow worked in Learned how Timer 0 Overflow worked in
relationship to counting the periodrelationship to counting the period When overflow occurred, decremented When overflow occurred, decremented
the octave and reset the divide by 2^nthe octave and reset the divide by 2^n Once a pitch is successfully detected, Once a pitch is successfully detected,
reset the divide by 2^n to the 9th reset the divide by 2^n to the 9th octaveoctave
Device is then ready to search againDevice is then ready to search again
Milestones & CriticalMilestones & CriticalProblemsProblems
Critical ProblemsCritical Problems– Unit did not work initiallyUnit did not work initially– Not enough memory to expand LED’sNot enough memory to expand LED’s– Lack of software for manual tuneLack of software for manual tune– Parts for AGC did not come inParts for AGC did not come in
Milestones & CriticalMilestones & CriticalProblemsProblems
MilestonesMilestones– Getting unit up and runningGetting unit up and running– Expanding tables for LED’sExpanding tables for LED’s– Determined a good duty cycle and Determined a good duty cycle and
waveform for the Audible Reference waveform for the Audible Reference Pitch with a function generatorPitch with a function generator
– Determined design for AGC circuitDetermined design for AGC circuit– Successfully implementing Auto Tune Successfully implementing Auto Tune
ModeMode
Future WorkFuture Work
Manual TuneManual Tune Audible Reference PitchAudible Reference Pitch Expanded LED DisplayExpanded LED Display PackagingPackaging Automatic Gain ControlAutomatic Gain Control New Hardware:microphone, New Hardware:microphone,
speaker, CPU, and memoryspeaker, CPU, and memory
Any Questions?Any Questions?