I have a processing sketch that sends data out a single serial to an Ardunio board, and from there drives two 4-pin steppers.
I would like to double the number of steppers, due to the amount of pins this requires a second Arduino board to take input from the processing sketch.
Is there a way to tell processing to write outputs to 2 different serials?
I own arduino nano, which has only one serial port so I use NewSoftSerial library to create additional port, you can get the library here NewSoftSerial | Arduiniana
you could create additional port with newsoftserial and then send data to it right after you've send data to "primary" port