Uncle Roger wrote:
Because the Atari (same as commodore and others) joysticks are digital
(on/off for each direction; done with simple switches) instead of analog
(varying amount of each direction; done with potentiometers) like most PC
joysticks, it is rather easy to build alternative input devices, whether
it's something to stand on, or a bunch of buttons, or whatever.
I think the other pins (5, 7, 9) were used for the paddles (which were
analog devices.)
Back when the Atari 400 was introduced, I got hooked on Space Invaders.
I found the Atari and other Joysticks to be a complete waste when it
came to playing Space Invaders since the these joysticks were 8-position
and it was too easy to move the stick to a diagonal position and get
killed on the game. I considered what a 10 pound sledge hammer might do
to that 8 ounce stick, really liked the thought, but decided a more
rational approach was needed :). At that time, a well built 4-position
commercial quality joystick became available at only about $18 or so, so
I built a dozen units or so and they were sold through a computer store
a friend of mine owned at (I think) about $45 each. Ah yes, nothing
like the "good old days"!