Chances are you’ve never wondered what your goldfish is trying to say, but if you have (or if you just want a project), check out this DIY hydrophone.

You will need a computer microphone, vegetable oil, plastic wrap, scissors, solder, and a small unused plastic bottle. Solder the mic capsule to an appropriate length of cable and test. The entire assembly can then be submerged in vegetable oil inside a plastic bottle. Yes, vegetable oil. Seal the bottle and you’re done.

14 thoughts on “Hydrophone

  1. This would be much more exciting as part of a DIY sonar system.

    I might have to investigate the feasibility of close range 3D sonic imaging. It would be awesome to make some goggles that would let you see in the murky black depths.

  2. i have done something similar but it wasn’t quiet as dedicated. all i did was take my microphone put a non-lubricated condom over it, used a zip-tie to keep the water out and used a dab of silicone to seal the water out completely… i also use the same method for my mp3 player whenever i go rafting.

  3. Damn, I just noticed that you guys don’t use that “photo”-effect anymore when you post a picture.
    Click on the vegetable oil link to see what I mean: the picture has a border and those pieces of tape…

  4. i guess this would be an idea if you had a pool and needed something to monitor your pool or fish tank if you worried about something or someone getting into them

  5. so we have hit the bottom of the barrel now, have we?

    Instructables pretending to be “hacks” isnt fooling us, Mr Obrien.

    We visit instructables.com when we want crappy writeups by amateurs because we know how to use google and hackaday can only consume SO MANY HOURS in one day. What we dont know is what is on the cutting edge of hack-dom; a subject YOU SIR seemed to be well versed in for months and years previously…..but all of a sudden its as if you either forgot, or just cannot remember what made this site great.

    I am not complaining—–i am not wingeing—–I am making a statement of fact. Once upon a time, Myself and my peers eagerly sat up til 2 am some nights drinking caffiene in anxious anticipation of what clever thing you would find next. MANY is the hours i have spent trying to make sense of some schematic or drawing found on this site, but no more. Now, instead of feeling anxious anticipation——i come to this site feeling a bit like my uncle Will not only forgot about me, but did in fact trick me into letting him perform sodomy on me before he tossed me aside.

    Are we not human? If you prick us, do we not bleed? WE GROW WEARY OF THIS INSTRUCTABLE GARBAGE MASQUERADING AS PROPER HACKS!!!

    Your fanbase is speaking to you, Mr Obrien…..and what they are telling you is that they (we) feel left out in the cold.

    someone will call for a boycott of hackaday soon if you keep this stupidness up. The hours i used to spend lovingly perusing this site shall be wasted on better efforts, like emailing all of your advertisers to tell them what a great job you are consistently failing to do.

    We ALL have grown to expect MORE from this site than this kid stuff garbage. Shame on you, Mr Obrien.

    No writeup?
    No schematic?
    NO HACK!

  6. Zoinks is being a little too critical, but I agree to a point that I have seen many amazing things on this site, but lately I’m seeing more and more uninteresting stuff being posted. I’m pretty certain that lots of people aren’t posting as many hacks anymore just because their incredible ideas are making them money elsewhere. Just a guess.

  7. @zoinks

    there’s no schematic because its not an electronic circuit, and there is a write-up, so by your definition it is a hack. you don’t like what’s on here? then find or do something better and use the submission line

    i also don’t know why a smaller container wasn’t used, but chances are they just used what was on hand to get the job done. what i was thinking was would it be better to skip the oil and maybe glue the microphone directly to the inside of the container, i think that should give adequate sound transfer, without the possibility of oil leaking out into whatever you’ve got it dipped in

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