DIY Hydrophone

A simple tutorial to do an hydrophone (aquatic microphone), step by step. Do It Yourself following each step below.


  1. Mic cable (mono)
  2. Thermofit
  3. Piezoelectric sensor (on our video we used a 1″ piezo)
  4. Plastic lids or “feet” for chairs or tables (with a diameter about 1cm bigger than piezoeletric’s diameter)
  5. 1/4″mono jack plug 
  6. Iron washers
  7. Rubber coating
  8. Copper foil
  9. Solder
  10. Silicon
  11. Electric tape


  1. Cutter
  2. Scissors
  3. Drilling machine
  4. Drill
  5. Hole saw (with a diameter a bit smaller than piezoelectric diameter)  
  6. Cutting plier
  7. Soldering iron
  8. Ruler
  9. Permanent ink pen
  10. Lighter


_ Choose a plastic lid with a diameter about 1cm bigger than piezoeletric’s diameter. In our video we used a 1″ piezo (25mm)
_ With a ruler mark the center of the plastic piece
_ Make a hole with the drilling machine and the hole saw.
(The hole saw diameter should be a bit smaller than piezoelectric diameter)
_ On the side of the plastic lid make a hole with the drill. It’s where the mic cable will pass through.


We will use the copper to protect the hydrophone from electro-magnetic interference.
_ Measure the plastic lid height
_ Cut the copper foil as a strip with the same height.
_ Take the copper strip and internally cover the lid.
_ Fix the copper ring with electrical tape
_ With scissors cut a hole on the side of the ring
Note: it exist a self-adhesive copper foil which could be better for this use (and easier to work with)


_ Position the piezo centered outside of the lid. The terminals must be seen inside the hole.
_ Fix it with electric tape. It will be removed on step 5.
_ Before soldering put 2″of thermofit on both sides of the cable.
_ Pass the mic cable through the lid and copper holes and solder it on piezo’s terminals : ground on the external part, positive on the internal part of the piezo.
_ Solder the 1/4″mono jack plug  on the other side of the cable.
_ After soldering, reposition the thermofit and get it hot with the lighter.
Note: it would be possible to use a stereo cable to have probably better shielding. You should then connect ground to the copper foil, positive on the center and negative on the external part of the piezo. 

STEP 4 | Silicon and iron washers

_ Fill half of the lid with silicon.
_ Put 2 iron washers inside it. (In order to give some weight to the hydrophone)
_ Fill the rest of the lid with silicon.
_ Cut a copper foil circle, with the same diameter as the lid.
_ Put the copper circle on the top of the silicon, so it will get glued._ Wait until the silicon dries (about 30 minutes)
Note: you could put some weight on top of the copper foil, so it will get straighter.

STEP 5 | Rubber coating

_ Carefully remove the electric tape from the piezo.
_ Dip the lid in the rubber coating can and take it out very slowly.
_ Let it dry for around 30 minutes and repeat this step 2 or 3 times.
_ For a uniform rubber layer, you can turn the lid upside down while drying

STEP 6 | Listening

_ Try your hydrophone and share your recording 
_ Enjoy

TUTORIAL by Sara Lana & Félix Blume

Other nice hydrophone tutorials where we learned to construct ours:

If you want to buy some, here are a few links :

Missing a link to a nice DIY tutorial or another nice way of buying an hydrophone? Contact us!