A simple design (idea) to allow you to move the mouse pointer with hand gestures. This design used a LED and 9 photocells to watch shadow movements cast by your hand, and then convert that to mouse pointer movements on your computer.
Step 1: The Idea
The idea for the "Air Mouse" was to be able to control your computer simply my moving your hand trough the air. Each photocell is arranged in a 3x3 matrix to detect the shadow cast by your hand so the microcontroller can determine in witch direction to move the mouse pointer. A LED raised above the device will help create a sharp contrast between the shadow of your hand and every ware else. The advantage of this design is it doesn't matter what hand you use, you could even use your foot if you really wanted.
If a shadow is detected over the central and bottom center photocell then the mouse will be stationary. A shadow over every cell in the middle vertical column indicates a up movement. Just the bottom center is a down movement. Right center and right bottom is right, all the right hand row is up/right, just bottom right corner is right/down, and all this mirrored for left movement.
It's a fairly simple design, and the device itself wouldn't be hard to create. The challenge would be in the programming, and even that shouldn't be too overly difficult. If you got really creative you could very the speed of the pointer by watching how much shadow is over a particular photocell. If you used an IR led and a photocell capable of detecting IR light you could make a design that won't light up the room and create glare, while not being to influenced by bright lighting.