1. Kareem Nammari Edward Nicholson Kari Skupa Wes Stanway Cui Sun 1

2. This is a surveillance device that will use a laser to pick up vibrations on a surface and convert it to sound. 2Cole

3.  Use a laser to measure the vibration on a surface.  Save and playback signal.  Be able to post process the signal.  Identify the audio source. 3Cole

4.  Covert Surveillance  Distance Measurements  Vibration Monitoring 4Cole

5.  Allows for long range surveillance  Difficult to detect  Needs stable environment  Alignment 5Cole

6.  Relatively Cheap  Reliable Data  Hard to Detect  Established Market 6Cole

7.  Working laser based sound detector ◦ 45º Bounce System  Basic filtering  Data output over Serial  Terminal Control 7Cole

8.  Working Laser Sound Detector Using Interferometry  Multiple Analog Filters  DSP  Serial I/O ◦ Terminal Control ◦ Serial Communication to Matlab 8Cole

9.  Wireless Communication to Computer  Data Storage  LCD Display  On Box Options ◦ Fourier ◦ Filter Selection ◦ Output on Display 9Cole

10.  Why use an interferometer? ◦ Sensitive to small signals ◦ Perpendicular setup  Complications ◦ Phase difference between beams ◦ Coherence Length 10Kareem

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12.  To get a good signal at the sensor ΔL needs to impart a phase shift in the laser beam of φ radians.  φ must be such that the intensity of the combined wave falls in one of the linear regions of Cos(t)+Cos(t+φ). 12Kareem

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14.  Small signal leads to low distortion  Large signals will produce a frequency that is a multiple of the original.  Differential measurement reduces distortions 14Kareem

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19. Post Processing Interferometer Detector Analog Filters Audio Amplifier A/D Converter Microprocessor Audio Out Software I/O Matlab Selector / Mux Audio Source POWER Laser Optics SPI Terminal Hardware RS232 Memory +5 V ±15 V +3.3V 19Wes

20.  Filters ◦ Minimum filtering is an anti-aliasing filter right before the A/DC.  Audio Amplifier  Detector  A/D converter 20Wes

21.  Coherence  ΔL  Bandwidth small enough for ΔL 21Wes

22. RequirementsSilicon DiodeHeNe Gas LaserDFB Coherence Length1-10nm30cm0.07-100m Wavelength375-2680nm632nm808-2000nm Power5V 100mA1250V 4mA3.2V 100mA Cost$3-30$10-200$50-1000 SizeSmall PackagesLarge TubesSmall Packages 22Wes

23.  Range from Class 2 to Class 3B  Class 2 ◦ Safe because of Blink Reflex (0.25 sec viewing) ◦ 400-800nm ◦ Limited to 2mW  Class 3B ◦ Hazardous if exposed directly to eye ◦ Diffused reflections are not harmful ◦ 315-2000nm ◦ Limited to 0.5mW 23Wes

24.  Photodiodes ◦ Respond quickly to photons. ◦ Provide a very small current.  Phototransistors ◦ Respond slowly to photons. ◦ Provide a moderate current. 24Wes

25.  Wall Wart (~20 Vdc @ 1 A)  Laser Driver  ± 15 V  + 5 V  + 3.3 V 25Wes

26.  A/D Converter ◦ Low resolution ◦ Separate chips  Serial I/O ◦ Terminal control ◦ Matlab communication  Memory ◦ Minimum capture rate of 44,100 samples per second ◦ Flash may be too slow. 26Kari

27.  MSP430 series ◦ 16-bit CPU ◦ 8-16 MHz CPU speed ◦ Up to 256 kB of flash memory and 16 kB of RAM ◦ Up to 80 I/O pins ◦ Built-in ADC/DAC components ◦ Low cost ◦ Low power consumption 27Kari

28.  Resolution ◦ 8 to 10 bits of resolution for audio  SPI interface ◦ Two Way Communication ◦ High Speed ◦ Low Power MCP3002 - ADS1115 - 28Kari

29.  Play back recorded audio.  Matlab ◦ DSP ◦ FFT  Terminal ◦ I/O interface ◦ Debugging 29Kari

30.  Serial Communication  DSP ◦ Filtering Specific Frequencies  FFT ◦ Voice Identification 30Kari

31.  Conceptual ◦ Simulate Optics ◦ Proof of Concept in Optics Lab  Hardware  Software 31Kari

32.  Window vibration in comparison to the wavelength of the laser  Alignment and spacing of lasers and beam splitter  Noise Filtering  Coherence length of lasers  Integration between Hardware and Software 32Kari

33.  Time  Budget  Physics  Knowledge Base 33Sun

34.  Standard Components  Precise Alignment  RoHS Compliance Capable 34Sun

35. KariSunColeWesKareem SoftwareAnalog Hardware SoftwareLayoutOptics Digital Hardware OpticsDigital Hardware Full SchematicAnalog Hardware Sound BoxPowerSound BoxPowerDetector OpticsPopulate Board Populate Board Budget 35Sun

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37. BlockEstimated Cost Laser$200 Optics$400 PCBs$100 Digital Components $150 Analog Components $200 Power$100 Demo Box$75 Expo Materials$75 Total$1300 37Sun

38.  UROP $1000.00  Attempt DEPS funding  Personal donation $100 each  Donation/loans of equipment 38Sun

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