hydrophone ideas needed

[grandislesail]

I am trying to come up with an inexpensive hydrophone for use on my sailboat (salt water). I picked up an assortment of parts lm386n-400mw, some consenser mic elements, some piezo transducers, assorted disc caps, and pot. assortment from radio shack. Any suggestions or cicuit ideas?
Wayne

 

[AllVol]

Attached is the basic circuit for an LM386 amp. How you capture the audio is another story. I also read your other post about piezo buzzers... I don't think they make very good acoustical microphones - more percussive, I understand.

 

[Hero999]

Please provide more information, do you want it to be half-duplex or full duplex?

What range?

How many channels?

If you whant full duplex or more than one channel, you'll need to shift an audio channel up to a higher ultrasonic frequency band and you might even want to consider using FM to reduce noise and increase the range.

 

[AllVol]

Do you think he can do all that with Radio Shack parts?

 

[Hero999]

Yes, I would think so.

 

[grandislesail]

Im not sure what you mean by duplex? The type of hydrophone im referring to is intended to listen, only, to dolphins and oher animals underwater. I should have explained that better. Frequency range 15hz to 20Khz. I just realized that "Dolphinear" www.dolphinear.com uses a piezo transducer,

 

[audioguru]

Why would anyone want to use only 2nd class parts and with a very small selection at a very high price from RadioShack??

Did you think that if you used FM ultrasonic transmission to the dolphins, then they would translate it so they understand it?

 

[Hero999]

not sure what you mean by duplex?

https://en.wikipedia.org/wiki/Full_duplex

Frequency range 15hz to 20Khz.

15Hz is infrasonic (below the human hearing range) and 20kHz near ultrasonic (is at the top) and you'll only be able to hear it if you're very young (under 20 or so). You might want to consider using some signal processing to make it easier to hear the low and high frequencies, heterodyning is normally the most commonly used technique.