My own rain water harvesting system has been great, however it can easily run dry after a few weeks without rain - I think it can consume and use water smarter.
Controls the out flow to the garden of caught rain water in the catch tanks in a smart way, based on many factors, such as how much water is left in the tanks, when the next rain will be and how much moisture is in the ground.
Using an Arduino to read from moisture sensors, a sonar for water level and a rain sensor we control when to pump water into the garden.
Reading sensors, building apps.
We were able to complete a final package for the sensor and pump.
Software is hard.