As the title implies, this is a guide on how to design, build and program a Mindstorm robot that shakes your computer's mouse. Why, you most likely will be wondering, would I ever want to use such an expensive thing for such a simple task? Well, because you can. The purpose of this robot is to keep your computer from going to sleep without having to change the settings. Yes, it seems utterly useless, but it's fun.
Needed Stuff:
~ A LEGO Mindstorms kit
~ A decent collection of LEGO Technic parts
~ A computer to program the mindstorm with (you're probably using one right now.)

Rather than give you step-by-step directions on how to build what I built, I'm going to explain key characteristics of the robot so you can design your own. However, feel free to duplicate my design.

There are 3 major parts of the robot: the Arm, the Claw, and the Motor Module.

Step 1: The Arm

this is what pushes the mouse. It works best if you extend the motor wheel with a 5-stud beam on each side and then attach another 2 beams between the cage and the 2 5s beams. Be sure that the 2nd beams are the same, and that they're longer than 5s. Also, you should be sure to raise up the motor so that the 5s beam on the motor doesn't hit the surface you're using.

Step 2: The Cage

This is what holds the mouse. The goal with the cage is to keep the mouse tight, so that you get the most out of the motor movement. It will need a bar on both sides of the mouse and points for the rotation arms to connect to. You may also want something to keep the mouse from sliding out at the top or bottom, like I have here. Be sure to build it to fit your mouse, unless you plan on using it for several mice. If that is the case, build it for the biggest.

Step 3: The Motor Module

Basically, the Motor Module is everything else. This is the motor, it's stand (see the Arm step, step 1), and the NXT brick. I recommend directly attaching your motor to the NXT brick. It adds weight and it keeps the robot together. Also, if you make the joint next to the cable ports, you can use it to keep the cable tucked away.

Step 4: Programming the Robot

Boot up the NXT programming interface, and code. Basicly, the robot sits and waits for X seconds, moves, then repeats it all. I also added something that, when the center button is pressed, it skips the wait and jumps right to the motor movement. See the picture for the finer details of the code, be sure to place the block connectors where needed, and modify it to your needs.

You're done! Go set it on your mouse, and feel confident that your computer will never sleep again.