A joystick is a computer peripheral or general control device consisting of a hand held stick that pivots about one end and transmits its angle in two or three dimensions to a computer. Most joysticks are two-dimensional, having two axes of movement, just like a mouse, but three-dimensional joysticks do exist.
Joysticks are often used to control games, and usually have one or more push-buttons whose state can also be read by the computer. Most I/O interface cards for PCs have a joystick (game control) port. Modern joysticks (as of 2003) mostly use a USB interface for connection to the PC.
Apart for controlling games, joysticks are also used for controlling machines such as elevators, craness and trucks.
An analog joystick is a joystick which has continuous states, i.e. returns an angle measure of the movement in any direction in the plane or the space (usually utilizing potentiometers) and a digital joystick gives only on/off signals for four different directions, and mechanically possible combinations (such as up-right, down-left, &c.). (Digital joysticks were very common as game controllers for the video game consoles and home computers of the 1980s.)
Additionally joysticks often have one or more fire buttons, used to trigger some kind of action. These are digital.
Joysticks were originally 2-axis controls for an aircraft's ailerons and elevators. They were fixed to the floor ot the aircraft and stuck up between the pilot's legs. The similarity in position to an erect penis meant that a slang term for a penis was applied to the control.
The first 4-axis joystick was probably invented around 1944 in Nazi Germany. The device was developed for targeting the glide bomb Henschel Hs 293 against ship targets. Here, the joystick was used by an operator to steer the missile towards its target by radio control. This joystick had on-off switches rather than analogue sensors.
This invention was picked up by someone in the team of scientist assembled at the Heeresversuchsanstalt in Peenemünde.
Here a part of the team on the German rocket program was developing the Wasserfall rocket, a successor to the V-2 rocket, the first ground-to-air missile intended for shooting down enemy aircraft.
(In these times the device was not associated with any kind of joy so it was simply called a control stick.)
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Technical details
History
