Theremillusion

University of Massachusetts Amherst

TheremillusionImen Ben NetichaSnigdha JonnaSandra JenkinsSteven Bennett

Advisor: Professor Siqueira

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Team Members

Snigdha JonnaEE

Steven BennettCSE

Imen Ben NetichaEE

Sandra JenkinsEE

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ResponsibilitiesSandra Jenkins• Pitch Variable Oscillator• Pitch Reference Oscillator• Mixer

Snigdha Jonna• Volume Variable Oscillator• Volume Fixed Oscillator Circuit and Voltage Control Amplifier Imen Ben Neticha• Fiber Optics/ Electroluminescent wires implementation• Designing and building driver for wires

Steven Bennett• Microcontroller Programming• Visual Demonstration Circuit

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Introduction Focus on making the Theremin easier

to play for beginners Incorporating a visual reference and

feedback− Player’s ability to hear tones focusing

specifically on the western scale Motivation: Electrical Engineering

based instrument

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Working with Music Department Professor

Professor Gary S. Karpinski frequencies used for equal

temperament This will help next semester when we

begin implementing the Discrete mode

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System Block Diagram

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Theremin (Volume Control Progress) The Volume Variable circuitry has been built The frequency is 385kHz which is a little low

compared to the goal of 440kHz There is still some unwanted noise, which is

affecting the frequency Noise due to bad connections in circuit

board− Making a PCB will be a good alternative for

reducing noise

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Volume Variable Oscillator

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Theremin(Volume Fixed Oscillator + VCA) The Volume Fixed Oscillator and the VCA

circuit has been built. The Volume Fixed Oscillator can be tuned

to have the same frequency as the Volume Variable Oscillator.

The VCA and VFO circuit are designed to increase the volume of the Theremin as the player moves his hand away from the antenna.

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Theremin (Pitch Control and Mixer) The circuitry has been built

The frequency is a little high, around 230Hz : goal is something closer to172Hz

Lots of unwanted noise from breadboards

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Fixed Pitch Oscillator

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Fixed Pitch Oscillator

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Variable Pitch Oscillator

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Variable Pitch Oscillator

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Mixer for Pitch Oscillators

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DEMO

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Software: What’s Been Going on

A Lot of Software Engineering:

Source File Lines of Code

Analyzer.c 340HardwareProfile.h 102USBDescriptors.c 307USB_Config.h 134NoteIO.c 413Main.c 688HelloUSBWorld.h 10HelloUSBWorld.c 435Total: 2429

• The Project is growing!

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Demo Software USB Control Selects

One of Two Sequences. LED sequences as

proposed at PDR. Proceeded with initial

ADC and FFT Code. Incomplete and disabled for demo.

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Why USB?

Demonstrations− Hooked up for reprogramming firmware.− Power board through USB hub.− Select a Song Sequence using a script.

Debugging− Variables and changes in state can be

printed back to PC.

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USB Demo Two scripts prepared to transmit control

characters to board through PC Com Ports.

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Demo

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“Canon in D” Original Theremin music is hard to find! Peter Pringle’s rendition of Pachelbel’s “Canon”.

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Musical Notes Note to I/O Database First 4 Entries

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Peeking into the Future: Analog and FFT

• Code implemented… but there is still very much to be done.

• Primary focus has been preparing LED sequence as outlined from PDR.

• Goal: Wrap up Note Framework so songs can be implemented in parallel with scoring and teaching implementation.

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Optical Fibers

Problem:Fiber optics are very dim. Light does not reflect very well because it escapes at the end.

Solution:Attach aluminum foil at ends of the fiber optic to create a mirror like reflection of the light.

Create narrow tubing to direct the light from the LED directly to the Fiber optic

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Electroluminescent Wires

Alternative Solution:

Electroluminescent wires (EL wires)

Problem: The PIC32 outputs a 3V DC and the EL wire

requires 120V AC input.Solution:

•Build a driver (power inverter)

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EL Wires

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Pros and ConsFiber Optics:Pros: Transparent thin Flexible No added capacitance to systemCons: Light dims as the fiber length increases Too dim when lit with LED An illuminator would be costly

Electroluminescent Wires:Pros: Flexible Thin No added capacitance to system Continuously Bright

Cons: Hard to cut Requires 120V AC input, but PIC32 outputs 3V DC Driver needs to be built

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Visual Interface Alternative: Driver Circuitry

12VDC to 120VAC inverter3VDC to 12 VDC converter

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Cost Analysis:

PARTS QUANTITY COST TOTAL

BC547 10 0.11 1.1

2N5486 5 0.55 2.75

1mH 5 0.82 4.1

10mH 8 0.82 6.56

330uH 5 0.82 4.1

Fiber Optics 10 feet 2.7 27

Glowing wires 10 feet 2.7 27

Microcontroller (PIC 32) 1 40

TOTAL COST (without shipping) 112.61

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Summary of Progress● Working circuitry for Volume Control● Working circuitry for Pitch Control● Working LEDS and optical fiber connections to connect PIC32 ●Working code and circuitry to play song using PIC32●Working on switching to Electroluminescent wires (glowing wires).

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How challenges from PDR have been Met

Solutions to previous problems•Working volume and pitch circuitry•PIC32 can play a song in correspondence with LEDs

Problems that have arisen•Fiber optics are too dim to distinguish in daylight•Snowstorm delayed many parts

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Current Challenges

Limitations of breadboards Optical Fibers alternative Integrating separate modules of the

theremin

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Revised Timeline Compare to PDR

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Update on final version for SDP Day

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END

Thank You!!!

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Parts ListPart PRO PVO VVC VRC and VCA Mixer Total .001uF 0 0 0 1 1 2.0047uF 0 0 0 0 2 2.01uF 0 0 1 0 0 1.012uF 0 0 1 0 0 10.033uF 2 2 1 0 0 5.1 uF 2 1 2 2 1 810uF 0 0 0 1 0 14.7pF 0 0 0 3 0 30-60pF 2 1 1 1 0 5200pF 1 1 1 0 0 3227pF 0 0 0 1 0 1270pF 0 0 1 0 0 1680pf 1 1 0 0 0 21mH 1 1 0 0 0 210mH 0 4 0 0 0 4330uH 0 0 1 1 0 210k pot 1 0 1 0 0 21k 2 2 2 1 3 106.8k 0 0 0 0 1 110k 0 0 0 2 0 233k 1 1 1 0 0 3150k 1 1 1 0 0 3330k 2 2 0 0 0 4470k 0 0 0 1 0 11M 0 0 0 1 0 11.2M 0 0 1 0 0 14.7M 0 0 0 2 0 2BC547 1 1 1 1 1 5Diode 0 0 0 1 0 12N5486 0 0 0 2 0 2

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References Kenneth D. Skeldon, et al. Physics of the Theremin. Department of Physics and Astronomy,

University of Glasgow, Glasgow G12 8QQ, Scotland. Received 15 May 1998; accepted 12 June 1998.

Way, Beng Koay; Douglas Beard, Micah Caudle, and Jeffrey Jun-Fey Wong. Theremin. Department of Electrical and Computer Engineering at Mississippi State University. <http://www.ece.msstate.edu/courses/ece4522/projects/2001_spring/theremin/>.

Holloway, Barry. Theremin. Strange Apparatus. 2009-2011. <http://www.strangeapparatus.com/Theremin.html>.

Sparkfun Electronics. “USB 32-bit Whacker – PIC32MX795 Development Board”.<http://www.sparkfun.com/products/9713>.

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Physics of Theremin

Antennas Difference between Analog/digital

theremins Physics of the variable capacitance and

how that changes the oscillators (how oscillators change sound)

Sandy email about finding theremin player

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Powering the theremin

Theremin can be powered by 12 volts. This can be done by building a step-

down transformer that will convert the normal house voltage or buy a power cord with a built in converter.

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Design Requirements Visual Display

− Will display current note being played and if in teaching mode, indicate how close the note is to target note.

Visual Reference (Fiber Optics)− Lights will indicate the general location the hand has to be in to

play a particular note.− (tentative) A light will change color depending on how close or far

away the sound is from the target note. Continuous and Discrete Playing Mode

− Device will be able to be switched between playing in the traditional continuous range and playing only discrete notes in specific frequency ranges.

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Software Interface

Modular Design

Visual Interface

Optical Fibers

Display

Output Processing

Frequency to Voltage

Tuning

Learning Mode

Output control

VCA

Audio Amplifier

Pitch Control

Variable Oscillator

FixedOscillator

Mixer/ Detector

Volume Control

Variable Oscillator

KnobVolume Tuning

Voltage to Frequency

Voltage Comparison/Discrete

OutputSwitch

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FFT Complexity

  FFT lengthMultiplies (real) Adds(real) Mults + Adds

Radix 2 1024 10248 30728 40976Split Radix 1024 7172 27652 34824

Prime Factor Alg 1008 5804 29100 34904

Winograd FT Alg 1008 3548 34416 37964

TABLE 1: Representative FFT Operation Counts