Suggestions for a DIY hydrophone?


Anyone have a link to instructions for a DIY hydrophone? This will be plugged directly into a laptop so no interface to OpenROV required.


Here was a basic towed array from NOAA:

#3 has a tutorial for a basic one. We’ve been kicking around hydrone ideas for a while. There was talk of trying to work with a few dolphin reserachers in Florida, but I haven’t had the cycles to follow up with it. Think we’ll get back to it over the summer though.


Thanks @Kevin_K and @Jim_N. I’m looking for something dead simple and cheap to build. Something along the lines of whatJim_N posted. Unfortunately that design uses 35mm film case, which you just don’t see anyone more. I saw some Instructables using piezo’s and plexiglass, but wondered if anyone had any better ideas?


Also check:


Thanks @Jim_N that helps too! :smile:


There is an old TAB book #1079 “How to build & use low-cost hydrophones” 1979 Frank Watlington ISBN 0-8306-1079-0. Originally it was $4.95. Amazon has a copy for $250. See if you can get one from a library or for under $10. It has lots of DIY info on building and using hydrophones, pre-amps, cables, housings, etc. mostly to listen to whales.


Thanks @Douglas_Butler, I remember the old “TAB” books ( ), I used to have quite a few of their books at one time.


Have you seen Dough Jacksons- SV seeker one


A fairly simple approach for a piezo disk based hydrophone was done at Stanford Center for Computer Music (CCRMA) by a friend of mine - Sasha. I have one and it works pretty well.



Jim I remember something about an acoustic modem from a year or so ago, sorry I’ve been out of it for a while, were you able to prototype it and test? It’s probably on the site haha my apologese if it is


Lots of good suggestions, thanks everyone! I’ve ordered a hand full of piezo’s and once they get here I’ll go about making the housing.


One more possibility for piezo-based hydrophones ( We’ve gone through a few iterations to make a cost-effective (<$50), robust, and functional hydrophone for education outreach and hobbyists alike. This includes an instructional video, written instruction guide, and materials list. Good luck!



Very nice addition to the list of DIY hydrophones. The quality of the instructional video was quite good. Also a nice mechanical design from inexpensive parts.

A piece of data I would like to have is the frequency response curve of the piezo-disk based hydrophone. Do you know if COS-TEK folks have done any testing to show the frequency response in water?

Yesterday at OpenROV Scrap Yard Hackday Thomas and I experimented with a submerged speaker in our test tank and listened to music thru the water to a piezo-disk based hydrophone using the same Radio Shack mono-amp. We did a short Periscope video demoing this - I will try to post to youtube.



Thank you, Jim. While we have had hopes to perform qualitative response curves of the hydrophone, it has only been qualitative to this point using Raven and/or Praat software. We have tested these both in the lab using submerged speakers and in the Long Island Sound with seemingly good success. I look forward to hearing more on your endeavors!



I have built a viable Hydrophone for the ROV using a Tascam DR-15. Complete instructions to come.