Kareem Nammari Edward Nicholson Kari Skupa Wes Stanway Cui Sun 1

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

 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

 Covert Surveillance  Distance Measurements  Vibration Monitoring 4Cole

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

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

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

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

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

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

11Kareem

 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

13Kareem

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

15Kareem

16Kareem

17Kareem

18Kareem

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

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

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

RequirementsSilicon DiodeHeNe Gas LaserDFB Coherence Length1-10nm30cm m Wavelength nm632nm nm Power5V 100mA1250V 4mA3.2V 100mA Cost$3-30$10-200$ SizeSmall PackagesLarge TubesSmall Packages 22Wes

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

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

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

 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

 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

 Resolution ◦ 8 to 10 bits of resolution for audio  SPI interface ◦ Two Way Communication ◦ High Speed ◦ Low Power MCP ADS Kari

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

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

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

 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

 Time  Budget  Physics  Knowledge Base 33Sun

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

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

36Sun

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

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

39Sun

40