Arduino with linux
Arduino is a small computer that connects to the pc with usb. Under debian with a 2.6.18-6-686 kernel it is detected automatically by the usbcore driver. Make sure the link on the Arduino is set to usb power and plug it into the powered on pc. The green LED on the Arduino should light.
and you should see some messages like this at the end of the output.
usb 1-2: new full speed USB device using uhci_hcd and address 4 usb 1-2: configuration #1 chosen from 1 choice ftdi_sio 1-2:1.0: FTDI USB Serial Device converter detected drivers/usb/serial/ftdi_sio.c: Detected FT232BM usb 1-2: FTDI USB Serial Device converter now attached to ttyUSB0
This means the Arduino has been detected. There will now be a device in /dev called ttyUSB0 or similar.
This is a normal character device and you can send text to it or read from it very simply.
echo foo > /dev/ttyUSB0
The text foo is written to the Arduino over the serial usb line. You should see the small orange and green LEDs flicker as the data is recieved by the Arduino.