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A trackball is a computer pointing device, similar to an upside-down mouse, where the user rolls a ball with their thumb or fingers to control the cursor on a screen instead of moving the entire device. The ball rests in a socket with internal optical sensors that detect its rotation along two axes, translating that movement into on-screen pointer actions. Trackballs are favored for reducing desk space, requiring less arm and wrist movement, and can be beneficial for ergonomic setups and users with limited mobility.

How it Works

The Ball: A prominent ball is held in a stationary socket.

Sensors: Inside the socket, optical or laser sensors constantly monitor the ball's surface.

Rotation: When the user rolls the ball with their thumb, fingers, or palm, it rotates against small internal rollers or directly under the sensors.

Signal Conversion: The sensors detect the patterns on the ball's surface and the resulting movement.

Cursor Movement: These detected movements are converted into digital signals, which are sent to the computer to move the on-screen cursor.