Monday, March 15, 2010

A Hydrophone for Fishing

One of the ideas we've been wondering about is what noises our lures make underwater. Many of them rattle on purpose, but what about the wobblers or others? Maybe the WD-40 we spray on is making them more quiet?

Last week we put together a couple of cheap hydrophones to try to hear sounds in the water.

Hearing and seeing sounds and lights that we humans don't normally experience is great fun with the kids. Bat detectors (ultrasonics), elk calls, UV and IR light, etc.
So... not its time to listen under the sea.

This is a simple and cheap design we found on the internet. A guys sells these as 'kits' on ebay, too.
We had a couple of the electronic 'listening' headphones already, so just needed some balloons. The balloon waterproofs the gizmo.
The biggest issue with a hydrophone is amplifying the signal/sound. These cheap microphone/amps take care of all that.

The microphones are only about $3 each. On one, we used the headphones. The blue one is for hooking up to the underwater camera to video and record the noises.
Zipties keep the plastic tubing tight with the balloon. We won't be going too deep, so the seal should hold...

These only take about 2 minutes to waterproof.
We filled the tubing with hotglue to seal it tight.


Here is one of our cameras, with the hydrophone / balloonophone attached.
Time to try it out.

Good thing we have wildlife available to test with. 4 of the original 7 goldfish are still active and kicking.
Dive! Dive! Dive!

The testing was alot of fun.
How did that kid get all wet?

Here is one of the shots chasing the fish around.
The color is a nice touch to the video. Makes it easier to follow the fish around, too!
Oh, here is how he got all wet!
In all of our experimentation and exploration, we have confirmed that ALL BOYS will get wet when water is remotely available.
We finished the testing using various lights and lasers to 'target' our quarry.
Someday we'll arm the goldfish with lasers so they can fight back...
Some tweeks are required to get better sound out of the hydrophone, but it should be ready for our fishing trips coming up soon!