Trackball
Trackballs are used in many laptop keyboards and earlier models of computer mice as the cursor control mechanism. The device looks like a turned-over mouse with a ball inside it and consists of a ball supported by a socket with sensors to detect rotation about two axes. Fred Longstaff and Tom Cranston created it in 1952. Basically, It is an input device is used to move the cursor on a computer screen. Applications for trackballs include industrial control, gaming, graphic design, CAD, air travel, nautical navigation, privacy, and assistive technology for the disabled.
What is a Trackball?
A trackball is an input device that consists of a protruding exposed ball held by a socket with sensors that detect the rotation of the ball. A trackball typically comes with one or two buttons that function similarly to mouse click buttons.