The biggest difference is that you will need two logic pins to control the sensor (Arduino digital out). This circuit is set up so that the two digital pins from Aruduino are used to flip-flop the voltage (running the current forward, then reverse). This back and forth current helps to cancel out electrolysis. That is not to say that electrolysis is not taking place. It is simply that the crust that is created by electrolysis is broken up when the current reverses. So the soil moisture sensor will operate effectively for a longer period of time.