Joystick to graphics interface?

[Technowanabee]

Can someone explain-or demystify- how a joystick controls a computer graphic. For example, a flight sim guage. Is it purely a matter of software, or PIC's of some type? If so, what type of software do they use, GIF animation, or what. Suppose you wanted to create a simple graphic to operate from a joystick on a PDA, do you somehow match the graphic software to the operating system? Any explanation would be appreciated-or steer me to a book, or site. :roll:

 

[ldril]

A basic joystick contains two potentiometers, one for the X and one for the Y axis. Inside the computer each potentiometer loads a capacitor and the time of loading is measured in software. The longer the time the bigger the value of the potentiometer. Thus the position of the joystick can be deduced from those two values (for X and for Y).

These values are then used by the program to do whatever it wants. For example change the pitch of a model airplane, increase throttle etc.

About the graphics - the gauge is just a bitmap over which the needles are drawn in the position given by the measured value.

For more info about joysticks just search on google. You'll find plenty of information. The same thing goes about computer graphics.

BR