Proximity Sensor Theremin

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

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

3. 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 …  Group 9: Theremin

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

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

6. Design • Module Requirements Specifications • Test Plan: acceptance, integration, unit • 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 Group 9: Theremin

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

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

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

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

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

12. Design Implementation Behavioral Schematic Group 9: Theremin

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

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

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

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

17. 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 Group 9: Theremin

18. Testing and Results • Results of Alpha Test • 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 Group 9: Theremin

19. 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 Group 9: Theremin

20. 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 Group 9: Theremin

21. Thank you for your attention Q&A