Senior Design IMid Semester Presentation

October 9, 2014

John CornEE

Alex GibsonEE

Jordan KleinCPE

Shane ReevesEE – Team Leader

Dr. KoshkaTeam Advisor

Team

• Problem/Market• System Overview• Review of Subsystems• Progress• Timeline

Outline

• Guitar interfaced synthesizers are virtually nonexistent• No guitars with lasers on the market• Market towards all musicians

Economic Practical Constraint:The Guitar must not cost more than $500.

Market

• Microcontroller• Lasers• Power Supply• Fretboard Finger Positioning• Synthesizer

Systems

Device Pros Cons

Arduino Due -84MHz CPU speed-2 DAC I/O pins -12 Analog I/O pins

Arduino Mega2560 -Currently owned-16 Analog I/O pins - 16MHz CPU speed

Microcontroller

Audio Latency Technical Constraint:The processor must detect a broken beam and output sound within 50ms.

Photodiodes must detect light wavelengths between 500nm and 600nm.

Light Detection Technical Constraint:

Photodiodes

[2]

[2]

Lasers

[3]

30mW Green Laser ModuleWavelength: 532nmOperating Voltage: 3VOperating Current: 360mA

Health and Safety Practical Constraint:The laser beams must be safe to the touch under normal operational conditions.

Power Supply

[4]

Device Quantity Voltage Current Total Current ( Three Hours )Laser 12 3 V 360 mA 12960 mA

Microcontroller 1 7 - 12 V 50 mA 150 mA

Synthesizer 1 3.3 V 18 mA 54 mA

Battery 2 7.4 V 6600 mAh 13200 mAh

Fretboard Finger Positioning

Technology Pros Cons

Membrane Potentiometers

- Easy to implement- Stable operation

- Expensive ($25 x 6)- Not visually appealing

Capacitive Sensing - Visually appealing- Inexpensive

- Difficult to implement- Requires significant calibration

Laser Time-of-Flight - Visually appealing- Precise measurements - Extremely Difficult to implement

Capacitive Sensing

• A simple RC circuit is used

• One plate of the capacitor is formed by a metal contact on the guitar and the other plate is formed by the finger of the player

• The time it takes for the Receive pin to read HIGH after the Send pin has been set HIGH will vary based on changing capacitance

MetalContact

Player’sFinger

~

Capacitive Sensing

• A simple RC circuit is used

• One plate of the capacitor is formed by a metal contact on the guitar and the other plate is formed by the finger of the player

• The time it takes for the Receive pin to read HIGH after the Send pin has been set HIGH will vary based on changing capacitance

Capacitive Sensing

• The 22 frets on the guitar will be used as the metal contacts

• Capacitive sensing begins when a laser beam on the neck of the guitar is broken

How Does a Synthesizer work?

By combining multiple sine waves and adjusting amplitude, a synthesizer can create a new waveform.

Synthesizer

Synthesizer

Technology Pros Cons

Arduino Synth Library -Easy to implement-Open source -Limited Functionality

SAM2695 Synthesizer -Extensive sound library-Onboard effects -Difficult to implement

The SAM2695 has functions for 128 instruments that support over 100 notes.

This will function like a keyboard that has multiple instrumental settings.

Synthesizer – SAM2695

Capabilities:•64-voice polyphony (without effects)•38-voice polyphony + effects•On-chip CleanWave™ wavetable data, firmware, RAM delay lines

Synthesizer – SAM2695

Synthesizer – SAM2695

[6]

SAM2695 -Low power single chip synthesizer with effects and built-in codec

48 pin package

Synthesizer – SAM2695

What is a codec?

A codec takes data and compresses/decompresses it so it can be transferred/received faster.

DataData CodecCodec DataData

Progress

• Formulated overall approach

• Lasers and photodiodes ordered and received

• Capacitive sensing tested

• Laser detection via photodiodes tested

• SAM2695 synthesizer chip ordered

• Issue with laser overheating resolved

Progress – Overheating Lasers

Progress – Pulsing Lasers

Timeline

[1] Available:

http://arduino.cc/en/Products.Compare

[2] Available:

http://advancedphotonix.com/wp-content/uploads/PDB-C142.pdf

[3] Available:

https://www.dx.com/p/30mw-532nm-green-laser-module-3v-11-9mm-26888

[4] Available:

http://www.all-battery.com/li-ion1865074v6600mahrechargeablebatterymodulewithpcb.aspx

[5] Available:

http://makezine.com/projects/make-35/advanced-arduino-sound-synthesis/

[6] Available:

http://www.dream.fr/pdf/Serie2000/SAM_Datasheets/SAM2695.pdf

References

Senior Design IMid Semester Presentation

October 9, 2014