I need some help with my Arduino project. I would like to create a small circuit that works underwater and display the water depth. The sensor and display part is done of the project but I get stuck with the on-off switch part.
Could somebody please help me with a decent circuit?
The basic idea the following: at "dry" conditions the circuit consumes zero power and when it gets submerged it will turn on my microcontroller. When the microcontroller finished the task it will turn off.
I would like to avoid the mechanical water switches.