How to build a auto sugarcane farm?

Hey,do you guys like farming?And sick and tired of picking sugarcane?
Now you all don't need to use hand anymore,just 1 button and you all settle it.It pretty easy to made.

Forgot something in the 1st build:
Put repeaters facing the pistons, Then a redstone line behind it. (Sorry for forgetting)

also, Having 2 rows of pistons makes it more efficient, try it yourself.
Video:

Watch and learned!!!