Parabolic 3D to capture sounds - microphone

Using Arduino Audio
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Hey guys,
I've been trying to capture sounds at a distance of about 220 meters for 3 months, I have a house that has an environmental reserve in the back, it has an open field and I would like to capture sounds of animals passing by a small lake at night , from birds to puma, it's rare but it exists in my region, I used a satellite dish on top of the roof, but the challenge is the distance.
Let's go to the details, so far I've used a 40cm dish that I printed on ender3, follow the project, Parabolic Microphone, 340mm by Zippitybamba - Thingiverse I increased the proportion and adjusted the central point, but it's not enough to capture sounds with quality at that distance, I also realized that the satellite dish does not have a narrow, directive beam! from what I understand it captures sounds at an opening of 60° degrees, as the distance is great maybe I'm losing sound.

This is a point I'm studying, for the tests I used the max9814 microphones, also the boya BY-M1, and now I've started studying the inmp441, it seems to be good, but I haven't tested it on the satellite dish yet.

1 - The tests with the max9814 were the best, but the noise is still loud and it's impossible to hear anything good at that distance.

2 - The BY-M1 has a clean sound, but it doesn't have the gain capacity compared to the max9814.

I would like some advice on how to improve this project, maybe it is not possible.

I thought of printing this parabolic project Big Boy - Parabolic Microphone by jkwalk87 - Thingiverse

I don't have a big 3D printer to print this dish, but I'll wait for your opinion first :wink:

Pardon my English, I'm using help from translate.
Some answers, I can't put the sensor in the reserve, I can't put a nail in the reserve, in addition to being too bureaucratic.

If I can capture sounds, the next step would be to use machine learning.

This project has no commercial purposes, it's just a hobby, I've already made a small dish for my daughter and she loved it, because I could hear birds much better, it was at this moment that I realized that I could maybe hear animals from a greater distance.

I put a picture of the parabolic.

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Two ways to increase gain. (1) Increase the diameter of the parabaloid (bigger physical area), or (2) increase the coefficient of the square (deeper curve).

[edit]
The "new" parabola will have a different focus.
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Any reflector will work. 3D the frame, and use smooth, non-porous, abundant material for the surface.

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I don't know about the parabolic part but I've seen that kind of thing before. They use them to capture the on-field sound at NFL football games and I think Radio Shack used to sell them.

The MAX9814 is the part number for a preamplifier chip, so that's a microphone board with probably 100 times more signal than a microphone alone.

When you amplify, you amplify the signal and noise together and the preamp adds some noise, which can be a problem with a weak signal (poor signal-to-noise ratio).

The MAX board should go into a line level input like "tape" or "CD" inputs on a stereo receiver) except it's probably DC biased for the Arduino. (The Arduino can't read the negative-half of a regular AC audio waveform.)

The BY-M1 should go into a microphone input, which means it's going into a mic preamp (built-into your phone, computer, or mixer, etc.).

...I was at a science museum once and they had a pair of giant acoustic parabolas facing each other. I don't know if they were 8 or 10 feet in diameter or maybe larger, but you could stand in front of one and the person at the other one at the opposite side of the exhibit space could hear you, even though the room was full of noisy people. It was interesting but it was a pair and somehow they worked together to transmit and receive the soundwaves with very little sound loss across the distance, and without the other sounds in the room drowning out the "focused" sound.

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I've been there. Unfortunately they are gone now. I read an interesting web site, about a DIY parabolic pointing straight up, apparently can capture sounds from high flying birds.

Thing to keep in mind is wavelength. Parabolics don't work well unless the diameter is (rule of thumb) at least 10 times the wavelength. That rules out most audio, it only works at extremely high frequencies.

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I understood about increasing the diameter and coefficient, thanks for the tips.

I really don't know about the new dish, I want to print it to see if I have a different result, there are no technical details, I'll have to try it, as it's a 20-inch dish, Big Boy - Parabolic Microphone by jkwalk87 - Thingiverse I need to see if I can print it on the ender3 :smiley:

About the print items, I'm already printing with 100% filling. I'm only using an 8mm nozzle so it doesn't take so long.

As I'm a hobbyist on weekends, as soon as I get some results, I'll come back here!

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I really couldn't find these dishes for sale here in Brazil and I'm also enjoying the challenge :smiley:

You're right, the MAX9814 really amplifies everything good and bad, I use it directly in the headphones, I only use a 220uF capacitor. Use with 40 dB gain.

About the amplifiers, I did some tests, I built some circuits with NE5532, it has a good result with little noise, I also tested with LM386 the result is reasonable and I also have a pre-amplifier mixing board MA-2S that has a good result.

Exactly, I use the BY-M1 on my cell phone to test the parabolic and I also use it at the input of the amplifiers.

About the museum, yes you are right! Here in Brazil we have something similar in college, Acústica - parabólicas - YouTube would be exactly what you commented.

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About the 10x rule, as I understand it, I would need to know which frequency I intend to listen to correctly? I'm amateur in sound :D, little knowledge. thanks for the tips!

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325-F5-DYI-Parabolic-Mic-PRIMARY
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Found here: [(link)] (How to build a parabolic microphone dish - Videomaker) That's a garbage can lid.

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Depends on what you mean by "work well" and of course, the wavelengths of interest. People very successfully use parabolic dishes of < 1 m diameter with microphones to record bird calls and human conversations at large distances.

Extensive tests and review of the Wildtronics product line here: Review: Wildtronics Parabolic Microphone Dish | Creative Field Recording

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I wish you well in your project. Cornell Uni, USA is interested in your results. (LINK)

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Remember, the English used them to detect German planes while still over the Channel!

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Not really. It just means, the high frequencies will generally always be good. As you increase the dish size, you get both more overall gain due to the greater capture area, and better directivity at lower frequencies due to the effectiveness of the reflector.

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Not even a satellite dish?

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I don't have that much time to dedicate to the project, but I promise to post the results here.

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surely this tutorial helps to understand the concept of parabolic, especially with the help of simple materials! cool!

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This tutorial was sensational, a complete class on parabolic and how things work.
The funniest part was about 20hz :grinning: really nice!

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We do have many parabolic resources for sale, but nothing specific to sound. With that, I preferred to do a 3D even to apprehend.

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It's true.

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How would you characterize that? Wouldn't any material that reflects sound be good enough?

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I built the shotgun mic from the June 1964 Popular Electronics magazine when it first came out. Not a parabolic style but easy to build with available parts. Worked great.

Sound Snooper

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