Super cheap optical microphone

A scientist here yesterday was talking to me about his technology white whale he’s been chasing for like three decades now. He used to do be research in Tucson Arizona, and there was an older guy working there who built a kind of really cool optical microphone.

He apparently used a like rangefinder/ focusing thing from an old SLR camera. And put like a lens in front of it into a little tube and then just had an analog amps and output to a sound thing. The scientists kept wanting the older guy to build another one for him or teach him how to build it but the older guy was a little stubborn I guess and then he died unfortunately.

The guy who made the things was named dr Hayward spangler Interview with Dr. Hayward Spangler on ant sounds, Acoustic Atlas Recording - Montana State University (MSU) Library

(The guy has done a lot of cool research projects, and also kind of sounds like Kermit the frog).

Does anyone here have any experience with this kind of design of an optical microphone? Or a different way of producing a really low cost optical microphone that can sense surface vibrations?

Basically the scientists here usually have to use a laser microphone for this kind of thing which cost like 20k.


Just guessing… I think your guy was focusing his telescope onto the ants stridulating bits, and projecting the blown up image onto a photodiode. As the ants noisemaking bits move, the photodiode output is modulated, which is then amplified and interpreted as sound.

Perhaps a the same effect can be obtained by examining the appropriate pixel of a high speed video camera trained onto the ant.

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Totally! Yeah I’m pretty sure it’s the same principal as when those people use there high-speed cameras and pointed at a chip bag and can reconstruct people talking in the room. But those high speed cameras tend to be expensive.

Vs, I think what you’re talking about, which sounds likely, It’s just using the high speed qualities of a photo diode hooked up to some kind of lens properly to get kind of similar results (lower spatial resolution I’m guessing, . Basically like one pixel)