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University of Massachusetts Amherst Theremillusion Imen Ben Neticha Snigdha Jonna Sandra Jenkins Steven Bennett Advisor: Professor Siqueira
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2 Grenzebach Glier & Associates, Inc. Team Members Snigdha Jonna EE Steven Bennett CSE Imen Ben Neticha EE Sandra Jenkins EE
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3 Grenzebach Glier & Associates, Inc. Responsibilities Sandra 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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4 Grenzebach Glier & Associates, Inc. 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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5 Grenzebach Glier & Associates, Inc. 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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6 Grenzebach Glier & Associates, Inc. System Block Diagram
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7 Grenzebach Glier & Associates, Inc. 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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8 Grenzebach Glier & Associates, Inc. Volume Variable Oscillator
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9 Grenzebach Glier & Associates, Inc. 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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10 Grenzebach Glier & Associates, Inc. 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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11 Grenzebach Glier & Associates, Inc. Fixed Pitch Oscillator
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12 Grenzebach Glier & Associates, Inc. Fixed Pitch Oscillator
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13 Grenzebach Glier & Associates, Inc. Variable Pitch Oscillator
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14 Grenzebach Glier & Associates, Inc. Variable Pitch Oscillator
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15 Grenzebach Glier & Associates, Inc. Mixer for Pitch Oscillators
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16 Grenzebach Glier & Associates, Inc. DEMO
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17 Grenzebach Glier & Associates, Inc. Software: What’s Been Going on A Lot of Software Engineering: Source FileLines of Code Analyzer.c340 HardwareProfile.h102 USBDescriptors.c307 USB_Config.h134 NoteIO.c413 Main.c688 HelloUSBWorld.h10 HelloUSBWorld.c435 Total:2429 The Project is growing!
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18 Grenzebach Glier & Associates, Inc. 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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19 Grenzebach Glier & Associates, Inc. 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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20 Grenzebach Glier & Associates, Inc. USB Demo Two scripts prepared to transmit control characters to board through PC Com Ports.
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21 Grenzebach Glier & Associates, Inc. Demo
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22 Grenzebach Glier & Associates, Inc. “Canon in D” Original Theremin music is hard to find! Peter Pringle’s rendition of Pachelbel’s “Canon”.
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23 Grenzebach Glier & Associates, Inc. Musical Notes Note to I/O Database First 4 Entries
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24 Grenzebach Glier & Associates, Inc. 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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25 Grenzebach Glier & Associates, Inc. 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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26 Grenzebach Glier & Associates, Inc. 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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27 Grenzebach Glier & Associates, Inc. EL Wires
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28 Grenzebach Glier & Associates, Inc. Pros and Cons Fiber Optics: Pros: Transparent thin Flexible No added capacitance to system Cons: 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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29 Grenzebach Glier & Associates, Inc. Visual Interface Alternative: Driver Circuitry 12VDC to 120VAC inverter3VDC to 12 VDC converter
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30 Grenzebach Glier & Associates, Inc. Cost Analysis: PARTSQUANTITYCOSTTOTAL BC547100.111.1 2N548650.552.75 1mH50.824.1 10mH80.826.56 330uH50.824.1 Fiber Optics10 feet2.727 Glowing wires10 feet2.727 Microcontroller (PIC 32)140 TOTAL COST (without shipping)112.61
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31 Grenzebach Glier & Associates, Inc. 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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32 Grenzebach Glier & Associates, Inc. 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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33 Grenzebach Glier & Associates, Inc. Current Challenges Limitations of breadboards Optical Fibers alternative Integrating separate modules of the theremin
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34 Grenzebach Glier & Associates, Inc. Revised Timeline Compare to PDR
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35 Grenzebach Glier & Associates, Inc. Update on final version for SDP Day
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36 Grenzebach Glier & Associates, Inc. END Thank You!!!
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37 Grenzebach Glier & Associates, Inc. Parts List PartPROPVOVVCVRC and VCAMixerTotal.001uF000112.0047uF000022.01uF001001.012uF001001 0.033uF221005.1 uF212218 10uF000101 4.7pF000303 0-60pF211105 200pF111003 227pF000101 270pF001001 680pf110002 1mH110002 10mH040004 330uH001102 10k pot101002 1k2221310 6.8k000011 10k000202 33k111003 150k111003 330k220004 470k000101 1M000101 1.2M001001 4.7M000202 BC547111115 Diode000101 2N5486000202
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38 Grenzebach Glier & Associates, Inc. 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.. Holloway, Barry. Theremin. Strange Apparatus. 2009-2011.. Sparkfun Electronics. “USB 32-bit Whacker – PIC32MX795 Development Board”..
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39 Grenzebach Glier & Associates, Inc. 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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40 Grenzebach Glier & Associates, Inc. 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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41 Grenzebach Glier & Associates, Inc. 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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42 Grenzebach Glier & Associates, Inc. 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 Fixed Oscillator Mixer/ Detector Volume Control Variable Oscillator Knob Volume Tuning Voltage to Frequency Voltage Comparison/Discrete Output Switch
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43 Grenzebach Glier & Associates, Inc. FFT Complexity FFT length Multiplies (real)Adds(real)Mults + Adds Radix 21024102483072840976 Split Radix102471722765234824 Prime Factor Alg100858042910034904 Winograd FT Alg100835483441637964 TABLE 1: Representative FFT Operation Counts
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