Laser Microphone

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  Laser Output

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  Reflection Reciver and Amplifier

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  Reflection off Window

Inspiration

We've always wanted to build one, so now we have.

What it does

It bounces light off of a window and measures it's movement to listen to the sound inside the room

How I built it

We built it using a simple laser, an analog receiving circuit, and Matlab digital signal processing.

Challenges I ran into

The received signal from the window had a very characteristic noise on it, which would wash out the desired audio. To fix this, we sent the sound to a computer and used Matlab digital signal processing to selectively filter the signal and extract the desired audio.

Accomplishments that I'm proud of

Building an analog circuit which is sensitive enough to sense the vibrations of a window. Using Matlab's DSP was also more successful than we could have hoped.

What I learned

We learned about obtaining clean data from a noisy environment, and how to do simple yet effective DSP.

What's next for Laser Microphone

Whats next for the laser microphone is to increase its range, and the sophistication of the software used to extract the audio.

Built With

• analog