GROUP ONE Final Presentation

Anirudh rawat |ali sultan | basil dixon | Bryant donato

CLOUD BASED LASER MICROPHONE1Summary PointsCurrent Design For CompletionTechnical OverviewRequirements Met & MissedDesign ChangesUsage Sequence DiagramRaw DataFuture ConsiderationsDemonstration Video

OUTLINE After testing four different multiple circuit designs, we have assembled a working laser microphone combined with an audio amplifier that can pick up ambient conversations and musicOur prototype works at a distance 21 feet ( 7 yards) and is scalable to 10+ yardsWe have developed a working linux software platform that has an automated script that works.We have also expanded the design added a windows platform for ease of use and compatibilityWe can pick up ambient music, audio, and background sounds off multiple reflective surfaces, including glass, mirrors, and windows.

SUMMARY POINTSOur circuit uses a pre-packaged LM386 amplifier circuit which we customized to take input via a phototransistor. It is powered using a standard 9V battery, yielding over a day of battery life!A phototransistor replaced a photodiode because it is much more sensitive to light, and allows us to pick up human voice with greater accuracyWe soldered everything to the most compact breadboard possible, measuring roughly 1.5 inches by 2.5 inches.This was placed in a metallic project enclosure, that will act as a Faraday cage and ground to reduce interference (under certain conditions, we were able to pick up FM radio transmission and listen to 102 WVAQ).An onboard potentiometer controls volume (amplification).A standard 3.5 mm output jack allows a user to record audio to a computer or use headphones to listen to audio.The design has changed very little from our original concept

TECHNICAL OVERVIEW

TECHNICAL OVERVIEW (contd).CURRENT DESIGN FOR COMPLETION

CURRENT DESIGN FOR COMPLETION

7Benchmark GoalStatusDetailsThe system is able to operate at 10+ yards.MetThe system operates at 7 yards, and is scalable to 10 yards. Outdoor testing was not done due to lack of timeAmplifies captured audio, and can be controlled via hardware and/or software.MetAn on-board potentiometer controls hardware amplification, & all software is capable of amplification.Stores audio as .WAVMetAudio is stored in .wavTransmits to databaseMetUsing SSH an automated linux script uploads our data to the cloud.The system is modular, neat, cost effective, runs on battery and AC power, and has a 1+ hour runtime.Met

All components are compact & can be easily replaced, and system costs less than $100. Battery life (1x 9V) has been clocked at over 1 day.

Benchmark Goal (continued)StatusDetailsMobile android application for database accessNot MetNot completed due to lack of timeOnline SQL databaseNot MetNot completed system remains open ended for user customizationDiode panel increases the capture area for the returning laserNot Met

Not completed due to technical difficulty and lack of time. Diode panel requires multiplexing circuit and increases the size of the hardware platform.

A prepackaged LM386 circuit was substituted for our hand-built circuit to guarantee quality, electromagnetic shielding, and robustness. The unit only added $7 to the cost of the project, which is negligible.MATLAB added to software platform filters and scriptsWindows added to software platform, along with audio processing software Audacity which allows for quick editing of .wav filesNote: Security is still a top concern, with SSH keys being required on the raspberry PiDatabase software not implemented due to lack of time.Interferometer setup was abandonded for two reasons:Project became too precise, bulky, and expensive. This was difficult to deploy quickly and easily in the fieldLack of time for implementation. A standard LM386 diode circuit worked just fine.DESIGN CHANGESUSAGE SEQUENCEFIELD TESTING!

RAW DATA CAPTURED

We have successfully used filters in MATLAB, Audacity, and other signal processing software.A combination of lowpass, highpass, and bandpass filters were used, but not thoroughly developed due to lack of time.Commercial, off-the-shelf programs like audacity do a satisfactory job with default filters.All of the programs were successful in removing various amounts of noise.

Unfiltered:

Filtered:

Drill holes in project enclosure to display power on/off LED, and to allow for control of amplification potentiometer. (potentiometer is currently set at 50% volume).Provide some kind of light shade on acquisition phototransistor to reduce ambient light noise.FUTURE CONSIDERATIONSLIMITATIONSProject limitations remain unchangedStable surface without vibrations is requiredThe more ambient light present, the more noise will be introduced into recorded audioA voltage delivery of at least 9 volts, (maximum 12 V) is required. Exceeding 9 volts is NOT recommended.DEMONSTRATION VIDEOQUESTIONS?