WEMOS DIY Water Leakage Sensor article that contains the code, libraries, diagrams, 3D print files and more information promised in the step-by-step youtube video below
Hmmm, I double checked I guess the board I grabbed is called a D1 mini but it's a different version than what you referenced. I'll try the one you have.
I've tested the deep sleep functionality but it doesn't seem to work at all.
-Ran 4 different boards, all matched the ones you have.
The ESP.DeepSleep function just doesn't seem to work. Tested with soldered and unsoldered connections.
Pins all work fine from my tests otherwise just deep sleep hates life.