Hello, I am currently working on a new product that requires a sound to be produced from small/thin waterproof speakers. The product is powered by a hydro turbine and micro-generator. The product will have the ability to be turned on and off but when it is turned on I would like it to produce the sound only when submerged.

Are there sensors that will detect when an object has been submerged to then signal the speakers to produce the sound?

Any help would be much appreciated!

Thank you.

 

Are there sensors that will detect when an object has been submerged[...]

Provided you aren't dealing with pure water, two contact points can detect water as the impure water will provide a current path between the two.

 

If it's just any water, then yeah, just a pair of electrodes will do. That's how they turn on dive computers.

 

The sensor can be as simple as a single MOSFET and a resistor: use 100K plus to pull the gate up, make sensor leads connected to ground and the gate. Ground source, and the drain becomes a connect to ground in water switch.

Some ESD protection for that gate would be a good thing, or get it free from inside any CMOS gate.