Hi,
I'm trying to emulate a keyboard with an Arduino Uno. I followed instructions at Project Log : Arduino USB - ProjectLogArduinoUSB and http://www.practicalarduino.com/projects/virtual-usb-keyboard. For now, I use VirtualUsbKeyboard/VirtualUsbKeyboard.pde at master · practicalarduino/VirtualUsbKeyboard · GitHub to test.
My code compiles fine, using the IDE 0022.
When I plug the Arduino (using the added USB port, not the embedded one), on Linux, I have this:
May 16 21:01:53 localhost kernel: usb 2-1.2: new full-speed USB device number 79 using ehci_hcd
May 16 21:01:53 localhost kernel: usb 2-1.2: device descriptor read/64, error -32
May 16 21:01:53 localhost kernel: usb 2-1.2: device descriptor read/64, error -32
May 16 21:01:53 localhost kernel: usb 2-1.2: new full-speed USB device number 80 using ehci_hcd
May 16 21:01:53 localhost kernel: usb 2-1.2: device descriptor read/64, error -32
May 16 21:01:54 localhost kernel: usb 2-1.2: device not accepting address 80, error -32
May 16 21:01:54 localhost kernel: hub 2-1:1.0: unable to enumerate USB device on port 2
and Windows is unable to install driver too.
I think my code is right (mainly because it's not mine 
). So, for the circuit, I copy/pasted (I think, I probably made a mistake somewhere) the one at http://code.rancidbacon.com/ProjectLogArduinoUSB:
http://code.rancidbacon.com/images/DSC00343_arduino_mini_usb_shield_top.JPG and http://code.rancidbacon.com/images/DSC00344_arduino_mini_usb_shield_bottom.JPG for the reference, mine is here: Dropbox - 2012-05-16 22.15.13.jpg - Simplify your life and Dropbox - 2012-05-17 00.34.37.jpg - Simplify your life. The green, red, white and black wires are to the USB plug, black is GND, red is 5V, green is D+, white D-. The other red and black are to the GND and +5V of the Arduino. The orange one is to the pin 2, and finally the yellow, to pin 4.
If anybody has any clue about why it doesn't work...