This is still very much a 'work in progress'. I've collected all of the components that I'll need to get started; Actually, I've collected more than I need since I haven't yet decided how I want to determine the water level(s). That's why I have the water sensor, float switch, ultrasonic module and eTape all listed under 'components'. I don't plan on using all of them, and I'll probably go with the simplest methods to start with. Ultimately, I want to use the eTape to sense the pond depth so that I can log the levels as they change. In the meantime, the eTape has been fun to experiment with!
I'm going to need to check on two water levels- the pond level as well as the level in the water barrel. If the barrel is empty, I want to close the solenoid. Once I get everything working, I want to trigger an alarm as well if this happens.
A 12V AC adapter supplies the power needed to operate the solenoid. I'm using a 12V to 5V module to provide the correct voltage for the Arduino.