I didn't actually read the article. ;) Lots of horrible games listed. heh

There is another version of lightguns, that emit infrared light. The gun is a simple infrared emitter like a remote control, and the target area has 3 or more sensors that get different amount of light based on the direction of the gun. This allows the simple triangulation of the positon based on the different analog levels received by the sensors. When every sensor gets equal values the emitter is pointing at the center of the target area. This technology was used in elder east european made arcades, children's toys and some low budget military training systems. (you only needed to fit the emitter on a real gun and use a target board with sensors in the corners) One feature of this system is that it produces analog output from the sensor decoder so it could also be used with analog joystic ports. I would note that the technology does not depend on any screen types so it can be used for today's games too.

Viktor

This would be good for LCD monitors where you couldn't use the standard light guns

Well if you want to take the time:
http://www.geocities.com/mellott124/VRGunspec.htm
http://www.geocities.com/mellott124/VrZ.htm
http://www.coinopexpress.com/products/parts/shooting_parts/

There is a good starting point for Lightgun implementations and information. Other then that it comes down to a few things; If you can setup your game to work with a mouse (fire button = mouse button) then you can hack a gyro mouse (or other 3D mouse) to work with the system easily enough. You can also use a gyro module with something like an AVR or PIC (ICK!) if you want to build your own. Personally I'd use one of the USB AVR's and a gyro module (or beacon system).

- Jeremy