Is it essential to include drawings/schematics in my patent? Is there any way to convert color images into blue/white drawing somehow?
A patent application needs whatever drawings are require to explain the invention to one of ordinary skill in the art and to prove that you "possessed the invention" at the time of filing.
Most people will advise more detail rather than less, unless the detail obscures the understanding. If the circuit itself is the tricky part of the invention you definitely need it.
Unless there is some good reasons otherwise, patent drawings are black and white line drawings.