1. Proximity Sensor Theremin Khoa Nguyen Walter Hudson Dennis Gilbert G. Hewage Thushara

2. Group 9: Theremin Slide 1 OUTLINE Needs and Objectives Design Design Implementation Testing and Results Team work and Lessons

3. Group 9: Theremin Slide 2 Needs and Objectives Practicum project requirements 1 actuator 1 sensor 1 processing module Motivation of project Implement core knowledge into a working project Actually build something Experience the steps of project development, organization, design and testing And, of course, to be cool and creative enough to get an A …

4. Group 9: Theremin Slide 3 Needs and Objectives Traditional Theremin Plays music without contact Controls frequency and volume Antennas act as sensors Proximity Sensor Theremin Us e proximity sensors as alternatives Use a MCU for digital signal processing of volume and frequency Have same functionality with integrated speaker Moog Theremin

5. Group 9: Theremin Slide 4 Needs and Objectives Objective: Functional Prototype Initial Approach Volume Sensor Frequency Sensor MCU ADC Conversion Output PWM Indicator LEDs Record Playback Battery power Analog voltage User Interface Switches Speaker Create sound Sensor ModuleMicroprocessor ModuleSpeaker Module

6. Group 9: Theremin Slide 5 Microprocessor Module Accept all voltage levels of sensor inputs Operation modes: playback, record, loop Indicator LEDs On board memory for 10s of recorded music Pushbutton interface Sensor Module Measure distance up to 400mm Reaction time <50ms Accountable for background noise Speaker Module Audible range sound >5m Master volume control 50mW -1W power without heat sink frequency range 300Hz -3.4kHz Design Module Requirements Specifications Test Plan: acceptance, integration, unit

7. Group 9: Theremin Slide 6 Design Sensor Module IR sensors with individual LED and phototransistor IR LED Phototransistor IR LED Phototransistor 5VDC Supply VDC output Hand position Optimize signal range Background noise is unpredictable under different light conditions 5VDC Supply

8. Group 9: Theremin Slide 7 Design MCU ATMega 328P 5VDC Supply VDC output volume sensor PWM for Frequency Indicator LEDs Main power Record Playback Interface Switches Main power Record Reset ACITVE LOW 5VDC VDC output freq sensor PWM for Volume ADC PWM outputs Frequency 16 bit resolution Volume 8 bit resolution 8MHz internal RC oscillator Microprocessor Module

9. Group 9: Theremin Slide 10 Design Speaker Module Speaker 5VDC Supply PWM Freq NMOS GND PWM Vol Volume PWM Fixed at 31250Hz Duty cycle varies from 0 -50% Frequency PWM Fixed 50% duty cycle variable frequency approx. 480Hz – 5500Hz By anding signal average DC level is controlled- Volume

10. Group 9: Theremin Slide 8 Design Software Algorithm Play through read adc from sensors Is measurement > max value? yes Mode 1 play through Measure freq sensor Update freq PWM timer Measure volume sensor Update volume PWM timer Is measurement < min value? no yes Mode 0 No output Turn off freq PWM Turn off volume PWM Executable on timer overflow interrupt Return main idle loop

11. Group 9: Theremin Slide 9 Design Software Algorithm Record Interrupt REC pushbutton pressed Is vec index at max? Increment index Are vectors fully populate? no yes Mask pushbutton interrupt Mode 3 Playback Update freq PWM timer from freq vec Executable on timer overflow interrupt Mode 2 REC / play through Measure freq sensor Update freq PWM timer Store freq sensor measurement Measure volume sensor Update volume PWM timer Store volume sensor measurement Update vol PWM timer from vol vec Reset index no yes Resettable on reset pushbutton interrupt

12. Group 9: Theremin Slide 11 Design Implementation Behavioral Schematic

13. Group 9: Theremin Slide 12 Design Implementation PCB Board Wire Diagram

14. Group 9: Theremin Slide 13 Design Implementation Off -Board Wire Diagram

15. Group 9: Theremin Slide 14 Design Implementation PCB Board Layout Top Fill Ground Plane Bottom Fill Ground Plane

16. Group 9: Theremin Slide 15 Design Implementation Project Box Locate Frequency and volume Sensors on opposite sides Speaker placed on top Create a DJ tool

17. Group 9: Theremin Slide 16 Testing and Results Microprocessor Module AVR Studio 5 with Debugger Prototype type board with LEDs and Pushbuttons Code blocks were modularized tested/ integrated Sensor Module Different sensors were tested for voltage outputs Ambient level Optimizing dynamic range of sensors Speaker Module Most difficult was creating waveform Configuration was prototyped in capstone lab High voltage levels from inductive speaker kick back

18. Group 9: Theremin Slide 17 Microprocessor Module Accept all voltage levels of sensor inputs Operation modes: playback, record, loop Indicator LEDs On board memory for 10s of recorded music Pushbutton interface Sensor Module Measure distance up to 400mm Reaction time <50ms Accountable for background noise Speaker Module Audible range sound >5m Master volume control 50mW -1W power without heat sink frequency range 300Hz -3.4kHz Results of Alpha Test Testing and Results

19. Group 9: Theremin Slide 18 Team work and Lessons Experience of work division in Individual tasks: Work in parallel: quickly done Limitations on learning Whole team does every step: Work in series: slower process Every member knows every process, equal learning opportunity Some members do more some do less

20. Group 9: Theremin Slide 19 Team work and Lessons What we got and learned Divide and conquer No conflict between team members Design process is in constant flux waterfall/ spiral method “Work in series” is better for learning and preparing for capstone “Work in parallel” is better for Capstone project and real working environment Achieve the ultimate goal: have fun with the project

21. Thank you for your attention Q&A