ecen 4610 capstone university of colorado boulder, co 80303 january 29, 2009 school of rock pdr...

ECEN 4610CapstoneUniversity of ColoradoBoulder, CO 80303

January 29, 2009

School of Rock PDRCheyenne AberleDrew VeldhuizenSwain BrooksDan Reed

ECEN 4610CapstoneNow Presenting…Now Presenting…

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ECEN 4610 Dan Reed Cheyenne AberleSwain Brooks Drew Veldhuizen

Drew Veldhuizen

ECEN 4610CapstoneProject OverviewProject Overview

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ECEN 4610CapstoneDesignDesign

PCB mounted in body of guitar. Motors mounted to the back side of the head of

the guitar. Using DSP, A/D converters, and microcontroller,

analyze signal and control motor movement to achieve desired pitch.

User Interface via LCD touch screen. Multi-colored LED’s next to each string to

indicate in tune or out of tune.

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ECEN 4610CapstoneBlock DiagramBlock Diagram

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ECEN 4610CapstoneGuitarGuitar

Electric guitar Audio output jack on guitar outputs signal for

analysis Signal output via magnetic “pick-ups” already

built into the guitar Looking for guitar at local shops and online Based on measurements, torque on tuning

knobs requires 12 to 16 oz-in

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ECEN 4610CapstonePCB DesignPCB Design

MSP430 Microcontroller Motor Drives

Six drives will be built and used to control six stepper tuning motors, one for each tuning knob.

DSP Processing Chip Using Fourier Transforms, will process frequency of

each string and determine how far off it is from the correct pitch.

Accelerometer Used for effects similar to star power in Guitar Hero.

LCD/Touch Screen GUI for tuning presets, effects, and feedback to user

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Cheyenne Aberle

ECEN 4610CapstoneMicrocontrollerMicrocontroller

TI MSP430 16-bit microcontroller32 kHz, 1.8V to 3.6V, ultra-low-power Interface to DSP chip through I2C communication

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ECEN 4610CapstoneDSP ChipDSP Chip

Freescale Semiconductor DSPB5637124-bit Audio Digital Signal ProcessorUtilizes I2C communication with microprocessor180MHz core, 3.3V

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ECEN 4610CapstoneFilteringFiltering

Filtering performed in the microcontroller Ideally, strum all strings at once and circuit filters

signals, outputs information to each motor controller for optimized tuning

The guitar might need to be strummed 3 to 4 times to provide adequate data for the tuning circuit

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ECEN 4610CapstoneMotor DesignMotor Design

Stepper Motors similar to the Sure Step 83oz-in motor will be used to turn the tuning knobs on the guitar head.

Motors will be mounted on the head with wires run through the neck of the guitar to the microcontroller.

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ECEN 4610CapstonePowerPower

AC to DC Power Converter Plugs into 120VAC 60Hz outlet.Used to recharge the battery Also good application for use at a performance

Ensures guitar always has enough power for tuning during a show

Rechargeable Lithium-Ion batteryAble to supply enough power to tune the guitar a few

times before recharging is necessary.

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Dan Reed

ECEN 4610CapstoneUser InterfaceUser Interface

LCD Touch ScreenCreates a graphical user interface Allows user to select different tuning schemes

Drop D, double drop D, standard, etc User can also customize tuning scheme

Most logical would be a lay-over resistive touch screen for an LCD display

LED’sNext to each string below the bridge. Indicates in or out of tune for each string based on the

color (eg. Green for in tune, red for out of tune)

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ECEN 4610CapstoneEffectsEffects

Adding effects to the guitar can up-scope this project if neededDistortion, Wah Wah, Reverb, etc…

The XYZ accelerometer will determine which effect is enabled based on the direction the guitar moves.

Can increase (1) the ease of turning on effects and (2) the excitement of performances.

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ECEN 4610CapstoneImplementationImplementation

PCB will be set into the body of the guitar. Motors will be attached to the head of the guitar. The LCD touch screen can be mounted in the

front or back of the guitar body, whichever is more convenient to the user.

The rechargeable battery will be mounted in the backside of the guitar body with an input jack for the AC to DC power converter.

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ECEN 4610CapstoneScheduleSchedule

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ECEN 4610CapstoneDivision of LaborDivision of Labor

Drew VeldhuizenMotor ControlPCB Design

Dan ReedPCB DesignSoftware

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Cheyenne AberleDSPMechanical / Control

Swain BrooksDSPSoftware

Group Technical and User Manual


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Swain Brooks

ECEN 4610CapstoneBudgetBudget

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Item # Cost Per Item Total NotesGuitar 1 100 100Guitar Strings 5 6 30Stepper Motors 6 19 114Motor Drivers 6 20 120PCB 1 40 40Microcontroller 1 13.75 13.75DSP Chip 1 12.88 12.88Development Board 1 0 0 Borrowed from CapstoneMisc (cables, connectors, shipping, etc) 1 150 150Accelerometer 1 35 35Touch Screen 1 100 100LCD Screen 1 100 100A/D Converter 1 8.91 8.91D/A Converter 1 4 4Battery 3 25 75Battery Charger 1 25 25Flash Memory 1 10 10LEDs 10 0.1 1

Total 939.54

ECEN 4610CapstoneExtra FeaturesExtra Features

Accelerometer USB output used for recording Visualizer on LCD screen and/or LEDs

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ECEN 4610CapstoneRisksRisks

Not everything will fit inside the guitarCreate external enclosure to house electronics

Motors might end up being too large to fit on the head of the guitarSeparate free standing enclosure for motors

Touch Screen does not workUse LCD and push buttons

Not enough time for effectsNot essential for project

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ECEN 4610CapstoneFall Back PlanFall Back Plan

LCD user interface with corresponding buttons. Set tuning schemes, not customizable. No effects, accelerometer used to activate the

tuning program. No battery, just use power cable.

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ECEN 4610CapstoneQuestionsQuestions

Any Questions?

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ecen 4610 capstone university of colorado boulder, co 80303 january 29, 2009 school of rock pdr...

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