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Project 16 Digital Whammy Bar. Tim Kamman | Jason Freeck | Parker Brown. 4/7/2014. Agenda. Introduction and Objectives PCB Design Evaluation Board Implementation Software design Sensors Requirements and Verification Conclusion. Introduction. Aftermarket tremolo bar Expensive
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Project 16Digital Whammy Bar Tim Kamman| Jason Freeck | Parker Brown 4/7/2014
Agenda • Introduction and Objectives • PCB Design • Evaluation Board Implementation • Software design • Sensors • Requirements and Verification • Conclusion
Introduction • Aftermarket tremolo bar • Expensive • Permanent • Difficult to tune • Limited shift possible • Solution: electronic implementation • Compact • Removable • Inexpensive
Objectives • High quality tremolo bar effect using DSP • Available at lower cost than existing options • Non-intrusive and temporary installation • Limited user setup required
PCB Design • Started with a single board design • ECE shop limitations → two board design • Power Board • Processing Board
Power Simulations • Simulated voltage regulator to determine power consumption • 92.08 mW
Power Budget • Typical 9 V Battery: 5.1 Wh
DSP Chip • Analog Devices ADAU1701: • Audio Processor • ADC/DAC built in • Sampling rates up to 192KHz supported • GPIOs
Output Filter Tolerance Analysis • Ensure cutoff frequencies stay above the desired sampling frequency • Maximum 5% change in component values
PCB Design: Cost Total: $93.72
PCB Design: Difficulties • Complex design • Bulky • Two boards • Limited by board layers/planes • Difficulty soldering • Burnt board
Evaluation Board Implementation Cost of Evaluation Board: $219.38
SigmaStudio • Proprietary software for Analog Devices DSP chips • Uses graphical blocks to program effects • Frequency shift included
Code Walkthrough Scale down input signal from sensor Set sensitivity mode
IR Sensor • Soldered IR sensor to 5 V power input • Bypassed current limiting diode
IR Sensor: Issues • “Cut-In” at middle of shift range • Accidental triggering during play • Digital artifacts from IR sampling
Potentiometer Sensor • Output Range: 0 to 3.3 V • Powered using external battery • Physical sensor • Better emulation of the feel of tremolo bar • More granular control • Purely analog, no sampling effects
Requirements and Verification Original Shifted -30 dB
Requirements and Verification Low Setting: Shifted to 387 Hz High Setting: Shifted to 287 Hz
Future Work • Provisional patent application • Mounting system • PCB board implementation • Lower cost • Power potentiometer off of the board • Physical tremolo bar
Conclusion • No digital tremolo bar available • Only alternative: aftermarket installation • Permanent • Invasive • Expensive • Digital tremolo bar can solve these problems • Low-Cost • Less Intrusive • Removable