Ok, I did my first steps to control an electro motor with arduino, today I bought myself a "learning package USB" from Franzis.
I plug it into my computer's USB port and it appears as /dev/ttyUSB0. I can then use it to switch on and switch off an LED.
Python program to play the note A (440 Hz):
import serial, time conn = serial.Serial('/dev/ttyUSB0', baudrate=9600, bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE, timeout=1, xonxoff=0, rtscts=0) while True: conn.setDTR(True) time.sleep(1/880) conn.setDTR(False) time.sleep(1/880)