hi, i have some problem with my mouse when using the arduino (to be exact 2 arduinos) - if i plugin the arduino the mouse jumps uncontrolled over the screen ands fires spooky click events. i am using a logitech rx300 mouse a arduino ng (with atmega168) and an older arduino (atmega8) - they are setup at comport 4 and 5, the mouse seems to use comport 1.
and suggestions how to fix that? ah - and i am using the latest ftdi drivers for windows xp (i am using win xpsp2).
regards andreas
hello
there is an easy explanation....
when the arduino sends some charaters back to the computer at certain speeds that stupid windows thinks you just plugged in a "MIcrosoft Ballpoint serial mouse" which was last sold probably in 1992... every character sent by arduino gets interpreted as mouse movements...
so you have to make your way to the "Control Panel" / System / Hardware and disable the driver... if you delete it , it will come back...
so just disable it...
it's a pain in the ass but windows is stupid and there is only one solution... upgrade to a mac 
massimo
oh ok, much thanks for your fast reply - in the first second i was a little bit shocked because i thought that i have broke the whole thing.
much thanks
m9dfukc
USB JUMPING MOUSE SYNDROME
Sorry to bring up such an old post, but I recently ran into this issue and thought I would post about how I solved it.
By default, Windows attempts to detect a serial port mouse while enumerating a COM port. If any data is streamed TO the PC from the COM port shortly after enumeration, the PC interprets this as belonging to a serial mouse and thus you get the crazy mouse jumping.
There are some fixes that involve messing with the boot.ini file or disabling drivers in the Device Manager, but I felt that these were too intrusive for potential end-users of my product (Uses Arduino bootloader and an ATMEGA328 but it's not strictly an Arduino.)
The problem first manifested itself when I migrated away from the pre-built Arduino and started using my custom PCB, which does not auto-reset when a serial connection is made (DTR and RTS are not connected to the FTDI chip.) With the Arduino, the board is reset upon initiating a serial connection, or when the USB cable is plugged in. This reset causes the bootloader to run and my Arduino program doesn't start streaming data until the bootloader times out. With the new PCB and no auto-reset, the bootloader times out before the COM port is even enumerated by the USB and the PC sees data as soon as the COM port appears - triggering the mouse events.
I solved this by rewriting my setup() function to wait five seconds before streaming any data. I flash some LEDs on the board to let the user know that something is happening, but an extra five seconds timeout will not impact the user at all for my application.
On future boards I will connect DTR to a digital input and suppress serial data when I see it asserted. I have several applications where I need the board to run unattended and unconnected to the PC, yet be able to connect without incident at any time.
Hope this helps!