Paddle controller

A paddle is a game controller with a round wheel and one or more fire buttons, where the wheel is typically used to control movement of the player object along one axis of the video screen. A paddle controller rotates through a fixed arc (usually about 330 degrees); it has a stop at each end.

The paddle wheel is usually mechanically coupled to a potentiometer, so as to generate an output voltage level varying with the wheel's angle relative to a fixed reference position. A paddle is thus an absolute position controller. That is, without any previous knowledge, the sensor can be read and the result directly indicates the position of the paddle knob. This is in contrast to a rotary encoder-based device or "spinner".

Paddles first appeared in video arcade games with Atari Inc.'s Pong in 1972, while the first console to use paddles was Magnavox's Odyssey that same year. The Apple II shipped with paddles until 1980. The Atari 2600 used paddles for several of its games, as did early home computers such as the Commodore VIC-20. True (potentiometer-based) paddles are almost never employed any more because they stop reading accurately when the potentiometer contacts get dirty or worn, because turning them too far can break them and because they require more-expensive analog sensing, whereas quadrature encoder-based controllers can be sensed digitally. Any recent game that has paddle-type control uses a quadrature encoder instead, even if the game uses paddles on screen (like Arkanoid).

The reason for the name paddle for this type of game controller is that the first game that used it, Pong, was a video game simulation of table tennis, whose racquets are commonly called paddles. Even though the simulated paddles appeared on-screen (as small line segments), it was the hand controllers used to move the line segments that actually came to bear the name. Some famous video games using paddles are Pong, Breakout, and Night Driver.

...
Wikipedia