Codebender is one of our favorite Arduino-related projects.  Vasilis and his team have created a browser-based platform for programming Arduino and sharing code.  They're doing the same thing we're trying to do: making it easier and more fun for beginners to get started with Arduino.  They're highlighting Kevin's April Fools mouse prank sketch.  If you haven't checked out Codebender already, now's a good time!
http://codebender.cc/

Boards for the new Arno Shield will be arriving soon. We should have available in 3 weeks. 

Here's a screen grab from the design software.  

We've tested and have everything working.  

So, if you already have an Arduino compatible board or want to check out the Arno system and leave room for moving on, this is for you.  It works best with a LeOlympia or Leonardo, but will work with an Uno or other 328 based board.

The Atmega 32U4 chip on the Arno has the capability of emulating a mouse and keyboard through the USB port.

I wrote a simple sketch that takes advantage of this to annoy your friends (or enemies).  There are several options in the sketch that can be selected and combined to get the effect you want.  

Basically, you set a time factor and the type of action to have the cursor do when the time comes around.  I made a Jitter routine that "shakes" the cursor and a Jump routine that moves the cursor across the screen.   You can add a beep to those to add to the mystery.  

View or download on Codebender

Plug your board into a USB port on the back of a PC or a USB hub that's out of the way and wait for the confused looks.  "Maybe it's a dirty mouse ball", "Are my eyes deceiving me?"...

With most computers you can plug the Arno in and the mouse and keyboard drivers will start working.  There may be a few driver install pop-ups in Windows, but it will eventually start working.  

This trick will work with other boards that have USB built in, such as our LeOlympia, the Arduino Leonardo, Sparkfun Micro and so on..

Link to Instructable