pointing deviceA Pointing device is one of the components in a GUI – graphical user interface. It is an embedded system that allows the user to select and operate manus within a system. The concept of pointing devices came in existence in 1970 and now it has become an essential component of GUI. Different types of pointing devices are available associated with various technologies. A pointing device can be connected to the system through cable, can also be a wireless or can use a stick that emits light beams or directly touched by sticks. Rugged pointing devices are also available to be used in harsh industrial environment.

MOUSE

Mouse is the most widely used pointing device. Without mouse a computer system is considered incomplete. The pointer moves on the screen with the motion of mouse on the pad. Mouse contains the sensors that detect the motion and send interrupts. Different types of mouse are available based on technology and interfaces. The mechanical mouse contains a ball and wheels for movement detection. Optical mouse uses LEDs (light emitting diodes) and photodiodes while Laser mouse uses Laser in place of LEDs to detect motion on mouse pad. The interfaces include mouse with two buttons or with three buttons. Moreover the cordless mouse is also available.

Trackball

Trackball is a pointing device that uses ball to move control cursor on screen. The ball is moved through hand palm and built-in sensors detect the rotation. Such pointing devices include integral buttons and clipped along with keyboard. This not only provides feasibility in use but also reduces covered area.

Touchpad

Touchpads are mostly found in Laptops. A touchpad is pad that works with user's finger. The finger movement controls the cursor motion on screen. Touchpads are covered with capacitive layer. Capacitive sensors are held along vertical and horizontal axis. The sensors determine movement as capacitance changes with finger touch.

Light Pen

A light pen points towards displayed objects by directly drawing on the screen. It works only on CRT displays. PEN allows drawing by touching the screen. You simply can carry and use with hand as no cables needed to attach.

Pointing Stick

A pointing stick controls the cursor movement with finger. Pointing stick resembles the eraser at pencil's top. It is integrated on keyboards commonly in Laptops. Pushing the pointing stick with finger controls the pointer movement on the screen. Applied forced is sensed by measuring material resistance. The cursor speed is dependent on the pushing force. For quite smaller systems it is the best possible solution.

Graphics Tablet

A graphic tablet can be considered a pointing device as it allows drawing hand images directly on screen. A graphic tablet is flat surface upon which one can draw through his/her hand. The drawing appears on the screen but not on the surface. A pen like apparatus called stylus is used for drawing along with an imaging program.

Other Pointing Devices

In other pointing devices there are joysticks, which are used mainly for the games. 3-D flying mouse that points in six different directions. Data glove has a shape like glove and works for virtual reality environments.