This was my one of very first project made with an arduino and solves a very common problem of our society- shortage of water. The device can be installed on any overhead tank and then you don't have to manually operate the water pump. The device will do it for you, withou even a drop of water being wasted.
Summary
This simple device solves a very common problem of our society- shortage of water. Using an ultrasonic sensor, it estimates the level of water in a water-tank and turns on or of the pump accordingly thus minimising the wastage of water from excess water running out of overhead tanks