ad wrote:
anyone around who understands how can one send control data to a stepper motor via the pduino aka firmata?
You have to set and clear the four digital outs that go to the motor.
i guess i have to send a message with few values at the same time: direction, speed, number of steps??
No it doesn't work that way. You have to explicitly set and unset each of the four control lines in a specific sequence. The speed you do it at determines how fast the motor turns. Each new step is a different pattern. To move the motor the coils have to be energized at one or the other side, not both. The sequence can be found by trial and error. When it's wrong the motor just jitters. It's not dangerous. Martin