University of Massachusetts Amherst Theremillusion The Thereminators: Imen Ben Neticha Snigdha Jonna Sandra Jenkins Steven Bennett Advisor: Professor Siqueira

2 Grenzebach Glier & Associates, Inc. Team Members Snigdha Jonna EE Steven Bennett CSE Imen Ben Neticha EE Sandra Jenkins EE

3 Grenzebach Glier & Associates, Inc. Responsibilities – Reallocations  Imen − EL Wires and EL Sequencer − Visual Output Control  Sandy − Theremin Integration and Troubleshooting − Discrete Mode  Snigdha − Theremin Troubleshooting − Discrete Mode  Steven − Displaying note accuracy programming

4 Grenzebach Glier & Associates, Inc. Invented by Léon Theremin in 1920 Background Originally got the idea while working on short wave ratio equipment and capacitive sensing during the Civil War in Russia

5 Grenzebach Glier & Associates, Inc. Motivations for Theremin Modification  No Reference  Continuous Pitch and volume  Need to have extensive ear training

6 Grenzebach Glier & Associates, Inc. How Does it Work

7 Grenzebach Glier & Associates, Inc. Theremin Principles  Beat Frequency Oscillators

8 Grenzebach Glier & Associates, Inc. Theremin Kit  Theremax Theremin − Volume and Pitch Antennas − Volume and Pitch field adjustment knobs − Timbre control: useful for external signal processing (aka Discrete Mode) − Manual for general operation and tuning

9 Grenzebach Glier & Associates, Inc. Discrete Mode-Theremin SWITCH Analog-to-Digital Converter in a PIC Controller Digital-to-Analog Converter Voltage to Frequency Converter SPEAKERS Frequency from the Theremin Discrete Signal Processing in MicroController

10 Grenzebach Glier & Associates, Inc. Arduino  Consists of a simple microcontroller board, and a development environment for writing software for the board.  This software was utilized to program the Discrete Mode of the Theremin.

11 Grenzebach Glier & Associates, Inc. Software in Arduino  Frequency measured with peak detection program  The frequency values outputted from the Theremin are grouped together to output a specific frequency based on frequency-to-note conversion.

12 Grenzebach Glier & Associates, Inc. Conversion table  Pitches.h

13 Grenzebach Glier & Associates, Inc. Theremin Data

14 Grenzebach Glier & Associates, Inc. Theremin Data

15 Grenzebach Glier & Associates, Inc. Theremin Data

16 Grenzebach Glier & Associates, Inc. Theremin Data

17 Grenzebach Glier & Associates, Inc. PIC32 DSP  16 Channel 10-Bit ADC  80 MHz, 1.56 DMIPS/MHz, 32-Bit M4K Core

18 Grenzebach Glier & Associates, Inc. FFT Demonstration  Configure IO Registers  Allocate and Prepare buffers.  256 Samples of Analog Signal at 10 KHz  Call Microchip Library Fuction: mips_fft16(dout, calcbuffer, fftc, scratch, log2N)  Meaningful Results: Magnitude/Frequency  Transmit Blocks of Data to USB

19 Grenzebach Glier & Associates, Inc. What’s Next  Analog Audio can be compared to a Musical Note Lookup Table  Derive a Score from Played Note vs Expected Note

20 Grenzebach Glier & Associates, Inc. Results

21 Grenzebach Glier & Associates, Inc. Why the EL Sequencer ● Easy to use, no need to re-invent the wheel ● Relatively inexpensive for the amount of hardware (in comparison to building one from scratch) ● Incorporates programming into the software ● Using a microwave transformer is more labor, more bulky, and not as accurate (results) ● Safer. EL wire is 100+V at 4000hz, but very low power. Instead of a shock, you will feel a small tingle if touched in the wrong places

22 Grenzebach Glier & Associates, Inc. EL Sequencer ● Board can be powered from USB or LiPo ● Switch chooses source and acts as on/off ● Compatible with Arduino (8MHz LilyPad) ● On-board 8MHz external resonator ● 8 TRIACs can handle up to 600V ● Control 8 channels of EL ● Runs on 3.7V LiPo ● Footprint for connection to FTDI Basic for downloading code ● Footprint for connection to Nordic nRF24L01 2.4GHz wireless module ATmega328 based control board that allows the user to program any sequence of blink, on/off, even pulse width modulation (PWM) pulsing of EL wire

23 Grenzebach Glier & Associates, Inc. TRIACs in the EL Sequencer ● While EL wire requires very little power, you can't use normal transistors to turn on/off a string of it ● So we use TRIACs → nifty 'switches' that allow you to turn on/off an AC source ● Triode for Alternating Current

24 Grenzebach Glier & Associates, Inc. Integration with PIC32 ● The EL Sequencer will guide the user with a series of lights. ● three levels (easy/medium/hard) ● PIC32 will compare and grade the user ● PIC32 interfaces with EL sequencer to display score on the EL wires

25 Grenzebach Glier & Associates, Inc. Theremillusion DEMO Glow Wires

26 Grenzebach Glier & Associates, Inc. END  Thank You!!!

27 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  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  Sparkfun Electronics. “USB 32-bit Whacker – PIC32MX795 Development Board”..  PAiA, “Theremax FAQ.”.

28 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 about finding theremin player

29 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.

30 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.

31 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

32 Grenzebach Glier & Associates, Inc. FFT Complexity FFT length Multiplies (real)Adds(real)Mults + Adds Radix Split Radix Prime Factor Alg Winograd FT Alg TABLE 1: Representative FFT Operation Counts

33 Grenzebach Glier & Associates, Inc. Reasons for the Theremin Kit  Building the Theremi  Comparable to creating an acoustic guitar for a woodworker

34 Grenzebach Glier & Associates, Inc.