Beck's Buddy wrote: ›
The pistol must work in sync with the game's graphics. I haven't take a look at the nintendo harware, but I'm almost sure it works like the ones in the game rooms at the mall.

Basically, the pistol has a lens that narrows the light coming in the front of it, (ie from the TV set) and send it to a built in optical sensor. Only light comming perfectly straight to the gun's shaft will make it in the built sensor.

The game graphics are made so that the possible tagets in the screen, in this case the fliying ducks, are constantly flickering between two contrasting colors. For example, the flying ducks can be changing from yellow to red and from red back to yellow every other frame, that is at a speed of 30Hz (30 frames per second) thus, it is so fast that to the human eye that what you see is amber color ducks, however, the sensor in the gun, can clearly see if the light coming in through the shaft is changing red, yellow, red, yellow.... So when this happens, the gun knows you are aming at something, if you happen to press the trigger at that time, the pistol sends to the console the "frequency of the flickering detected" through the cable.

Targets in the screen are flashing colors at different frequencies, (all some muiltiple of a frame), thus the console know, base on the readings of the pistol, which object you shot at. Since each object has diffent flashing frequencies, 30hz being the faster, then 28, 26,... etc... as it gets lower, the eye then start perceiving the flickering, so if the game has little targets visible at the time, you might not notice the flickering too much, but ten duck flying, you'll notice ones blinking more than others, so ther is a maximum of targets you can have at any given time which is the limit.


so, unless you write doom, with all enemies on the screen with a given flickering signature, there is nothing the pistol can read from the screen's incoming light.

For the other controllers, everything is happening though the cable. They are buttons (that you press or step over) to produce a signal to be sent to the console, and the game programming makes sense of it.

One thing you might consider is to build any control you like, then connect that to the PC serial port, and based on the input you receive from the external control you made, you push keys scancodes in the windows' messaging buffer, which are sent to the application in the foreground. Basically this is like building a driver (daemon) that press keys in the keyboard for you, but you are causing such events with some other input device.

For something like this, a place to start is the DirectX's Direct Input API.

: )

Nort wrote: › damn, yer friend sounds like a high end comp geek! my thoughts though, doesnt the glove itself detect movement? if so then you could use the glove to move the crosshair and just use the trigger on the gun to fire with, not actualy aim.