How to make a low cost Hydrophone


How to make a low cost hydrophone- Hear Fish Talk and Whales Sing!

 

BUDGET HYDROPHONE! HEAR FISH TALK

&

WHALES SING!


 

 

Jacque Cousteau's The Silent World is not really silent.

Hundreds of the nearly 20,000 species of fish make some sort of sound; there are popping pistol shrimp, chattering friendly dolphins and the spine tingling and hauntingly beautiful songs of the magnificent whales.

Sound travels nearly five times faster underwater than in the air. It travels 1500 meters per second under water as opposed to 331.6 meters per second in the air, and the sea bottom, sea surface and the separate layers of different temperature water help to transmit sounds underwater for miles and miles. The undersea world is not really silent at all!

I have always wanted to listen underwater without diving but have never had an affordable  hydrophone to try until now.

Recently, I bought a box lot of new, low cost electronic listening devices at an auction to resell. These were advertised as microphones that help to eavesdrop on the conversations of others. I tested one and listened to a distant conversation to see if they worked and was disappointed. I could hear the people talking but not much better than with my own ears.

However, I was surprised at other sounds it picked up. I could hear the sound of my socks on the tile floor as I walked across my living room and the low hum of the elevator in use outside my door- both sounds were inaudible without the listening device. It clearly amplified sound of a certain frequency.

I realized that although the device would be a failure at eavesdropping ( not really a bad thing) it would be great at picking up low frequency sounds. This led me to wonder how good it would work if I could try it under water.

I spent a day or two coming up with a way to waterproof one of the microphones and making it into a hydrophone. After I waterproofed it, the very first time I used it to listen underwater I was hooked.

Using this hydrophone I have been able to hear Dolphins right here in Biscayne Bay!! I have also heard a variety of other sea life, especially at dusk. Most of these sounds and the fish or other sea life that make them are unknown to me. I have not had the opportunity to hear whales yet, as this is not the place for them, but I hope to travel to where I can hear them in the future and I can hardly wait.

This is how I waterproofed the microphones and made them into hydrophones:

I used a small heavy duty rubber membrane (very thick balloon) to house the microphone and a short piece of thick rubber latex tubing to make the plug for the neck of the rubber housing. The plug was sealed with a core of  clay- the microphone cord runs through the plug. A plastic cable tie keeps the rubber membrane snug around the plug. A grease and oil free lubricant helped to squeeze the microphone into the membrane housing, and several coins used as weights were used inside the membrane as a way to help it sink.

 

The only drawback to the hydrophone is that the headphone wire lead is still rather short- only four feet long. A longer wire can be spliced on easily but it shouldn't be too long or you will probably reduce the sound it will pick up from the impedance of the wire. Four feet is long enough when you are on a small dock or in a low to the water, small boat or inflatable.

This is not a professional model hydrophone costing hundreds of dollars. This is just a low cost, but surprisingly effective listening device I recycled and made myself - a low cost, low budget, anyone can afford one, hydrophone!!!

 

How to make your budget Hydrophone

 

The parts you should have are the  listening device, 6 pennies (not shown), a balloon, a plastic wire tie, the headphones, a small piece of tubing, clay to seal the tubing, and a  non oil based lubricant. You will also need one hearing aid type battery ( Not shown)- either a "LI54" or an "AG13"

Note: Batteries may or may not be included . 

Check your listening device before buying a battery.

This is the electronic  toy listening device. 

 

These are the headphones.

 

This is a 9 inch  High quality Helium grade balloon.

 

 

This is the non hardening clay used to seal the tubing that has the headphone wire running through it. You can also use melted wax which is the cheapest or silicone sealant which is the most expensive. The wax works surprisingly well but will melt in high temperatures in your car, etc, and also requires additional weight to sink it. The silicone is the best material to use as it remains flexible but a tube of silicone once opened becomes worthless quickly even when the top is put back on securely so it is quite expensive to use. Overall the clay works well, especially the non-toxic non-hardening plastic type of modeling clay I provide in the kit.. Since you are only using the hydrophone at a couple of feet in depth it serves the purpose quite well. if you were going to splice a cord on the hydrophone to go a lot deeper you would need to use silicone.

 

Each penny weighs approximately 3 grams, you should only need 5-6 pennies to make the hydrophone sink below the water.

 

 

This is the water soluble  non oil based lubricant. If you use an oil based lubricant it will  cause the rubber  balloon to deteriorate.. In my first attempts I used talcum powder which worked as a non oil lubricant but was a disaster for the electronic parts as it was the same as bathing it in finely ground sand and quickly gummed up the switch.

 

This is the tubing used to make a a waterproof plug that the headphone  wire will run through and which you will seal the balloon with. You can use many types of tubing but the amber latex tubing shown is the best as it is soft and allows the balloon to be sealed tight around it to keep out the water.

 

Before assembling your hydrophone you should plug in the headphone  and battery and make sure it works properly. You also need to see where the on off switch is as you won't be able to see it once you place it in the balloon and will have to rely on touch to turn it on and off.

If you get a high pitched squeal when it is turned on you may be getting interference from other objects nearby, or your battery could be low or dying. Make sure the male headphone  jack is securely in the female jack of the listening device.

 

Remove the clip from the back of the listening device as it will make it easier to squeeze the device into the balloon.

 

Start putting your pennies that will be used as ballast  into the balloon.

 

Take your lubricant and grease the listening device and then insert the listening device into the balloon. Go easy as you do not want to tear the balloon. When you are done be sure to have the end that has the female jack at the mouth of the balloon. This is so  you can plug in the male jack of the headphone later.. Go easy as you do not want to tear the balloon. This is the hardest part. Once you get lubricant on your hands it is a chore to squeeze the device into the balloon. A second set of hands and some patience are very useful at this part.. ( Last time) Go easy as you do not want to tear the balloon!

 

 

Once the device is in the balloon it will look like this.

Go wash the lubricant off of your hands and thank the person helping you put the listening device in the balloon.

You are almost done.

 

 

Take the headphone and run the male input jack through the tubing

 

Take your clay and plug up the tubing solidly

 

 

 The sealed rubber plug is now near the end of the male input jack. Insert the male input jack into the female jack in listening device that you squeezed into the balloon. The rubber plug should now be sealing the mouth of the balloon. Squeeze out any excess air from the balloon and then when you are satisfied wrap the wire tie around the neck of the balloon and the sealed rubber plug. You want to make the wire tie  snug and tight but not too tight that it squeezes out the clay.

 

Cut off the excess of the wire tie but leave a tiny bit if you ever need to tighten the wire tie later. 


 

This is what the finished budget hydrophone will look like. Enjoy!

Robert  Moffett

© 2002

How to buy a Hydrophone Kit.

 

If you would prefer to buy a Hydrophone kit from me instead of

buying all of the seperate parts yourself I sell these little kits in my ebay store www.stores.ebay.com/mrhulot

 

or you may buy one from me here by sending $12.95 plus $2.50 shipping and handling. If you are outside the USA please add a dollar extra. There is no risk to you as I have a 30 day money back guarantee for any reason.

 

Thanks again. 

 

Robert Moffett

I HEARD THE WHALES SINGING TODAY WHILE I WAS KAYAKING!!! THANK YOU!!!
Buyer   travelnurse99 ( 231Feedback score is 100 to 499)  Mar-07-06 16:22 7210316672

 

great item and very well pacjkaged with instructions Buyer: kirkpas68 ( 61)  Oct-15-07 15:13
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130147923901) US $12.95 View Item

 Very honest seller, even refunded postage due to an accidental overcharge :) Buyer: darachnid ( 92)  Oct-15-07 03:27
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130161052723) US $12.95

Nice, fast, good quality. Simply perfect. What would life be without Mr Hulot? Buyer: slothheadtierchen ( 5 )  Oct-11-07 01:19
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130158599873) US $12.95

as described and packaged well, hope it works as described. Thanks Buyer: lasleyb ( 84)  Sep-10-07 17:05
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130146430337)

Cool item, interesting, thanks++ Great ebayer, recommended! Buyer: fatsrainbow ( 53)  Aug-13-07 07:35
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130136456394)

Simple, smooth transaction. Buyer: novaexpressllc ( 533)  Jul-05-07 16:10
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130121995547)

*+*+*++*SUPER*++*+*+*+*+*+*+* gerne wieder -)+++++++++ Buyer: percussionleo ( 16)  Jul-03-07 09:02
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130125853156)


no whales in this city but looks like a fun thing, good fast transaction, thanks Buyer: ropefactory ( 90)  Jun-24-07 04:38
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130122474593) US $12.95


‹(•¿•)› Fantastic E-bay transaction!!!!! Everything you said it is. Thank you... Buyer: lucky921dog ( 43)  Jun-20-07 19:07
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130125507792) US $12.95

 

excellent Buyer: bloodoftheelders ( 51)  May-09-07 10:13
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130093787251)

Excellent ebayer. Item arrived safely as described. Good instructions. Great! Buyer: sonicmagic ( 18)  Apr-19-07 05:20
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130079274561)

super fast shipping...super honest man...super cool kit...mr hulot rocks! Buyer: theseus726 ( 50)  Apr-16-07 11:48
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130096989438)

Pretty ingenious little gadget! Can't wait to try it out on the water. Thanks Buyer: 2wardogs ( 50)  Mar-12-07 16:06
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130079274561)


no problems Buyer: keb189 ( 26)  Mar-26-07 19:22
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130079274561) US $12.95 View Item


 super fast delivery from usa to uk ,cant wait to try out this wee gadget .A+++++ Buyer: coldhawkfishing ( 94)  Mar-25-07 09:44
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130088627738)

excellent kit. Thanks! Buyer: bernardroth ( 18)  Mar-30-07 15:42
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130079274561) US $12.95

Great product! Very fast shipping! Buyer: haleybo427 ( 42)  Apr-04-07 05:54
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130091883894) US $12.95


super fast shipping...super honest man...super cool kit...mr hulot rocks! Buyer: theseus726 ( 48)  Apr-16-07 11:48
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130096989438


Excellent ebayer. Item arrived safely as described. Good instructions. Great! Buyer: sonicmagic ( 17)  Apr-19-07 05:20
  Build a Hydrophone Kit Hear fish talk & Whales sing (#130079274561)

Cool little hydrophone kit. Works well, I attached a 1/4" plug and recorded it
Buyer   tmsoundguy ( 49Feedback score is 10 to 49)  Jul-05-06 16:30 7229364402

  joystick (4) Jul-02-01 1243520845 S
 

Praise : mrhulot made a great little device for listening underwater, cheap and fun

nice and ingenius device. great seller.
  Buyer  hamortar( 48)    Jan-31-07 04:59  130064420254

Everything as advertized
  Buyer   jim8gld ( 32)    Dec-28-05 11:58  7726677019

 good service, can't wait to try hydrophone, hope to hear divers on wreck.
  Buyer  wetranger( 6 )    Jan-08-07 20:07  130062328781

Excellent hydrophone exactly as described, thank you! Hope to do business again.
  Buyer  drlaurapost( 1061)    Jan-18-07 21:57  130064420254

nice and ingenius device. great seller.
  Buyer  hamortar( 54)    Jan-31-07 04:59  130064420254


Looks fun thanks!
  Buyer   dougkoester ( 12)    Jan-20-06 23:50  720737737

 Fast delivery. Interesting product. Thanks
  Buyer   rosa3994 ( 10)    Jan-20-06 17:36  7207389036
 
  interesting item
  Buyer   doctorize ( 206)    Jan-11-06 19:00  7208756983

U
  ilvandelmer(254) star Aug-11-01 1252923495 S
  Praise : I'm not a techie so I was worried about this purchase. But, it's fun.

User: obias (184) Date: Jun-10-01 03:08:00 PDT

Item: 584885139

Praise : great merchandise, easy to deal with -- thanks!

+1A+ Excellent transaction, trustworthy ->>> R E C O M M E N D A T I O N ! +1A+
  Buyer  pingupanic( 267)    Aug-27-06 09:32  7229364402


Hydrophone arrived quickly and was as described - haven't tried it out yet.
  Buyer  truespirit77( 12)    Aug-23-06 20:28  7229364402

as advertised, nice project ,easy to construct, fun   Buyer   leslie111diving()( 16)    Aug-07-04 06:09   3676387650

Excellent, thank you.Buyer skyroot( 229) Dec-15-06 06:50 130048424031

item as described;reasonable shipping. Positive ebay transactionBuyer mayda1234( 65) Nov-10-06 11:58 130037446830


Me a servido bienBuyer mostacilla( 3 ) Dec-08-06 10

A-OK.Buyer vvgreen( 675) Dec-07-06 06:38 130046898430


Back to Home Page: 

 NEMO 200 A Popular, Low Cost, Underwater Video Camera Housing