Short Note Points : short note on mouse, trackball, joystick, lightpen, microphone and digital camera Mouse: Mouse is also a primary input device but lacks the ability to easily transmit it textual information. It is also called pointing device that is used to move a pointer on the computer screen in order to point to a place on a display screen and to select one or more actions to be taken from the position. Trackball: A trackball is a pointing device that look like upside-down mouse. The function of trackball is same as of mouse, but you do not have to roll it over a flat surface. You use a trackball by rolling the ball with your palm or fingers in the direction you want the pointer to go. There are usually one to three buttons next to the ball, which are used just like mouse buttons. Joystick: A joystick is used only to play computer games. It is an input device, which controls the movement of a certain object is controlled by this handle, as well as the object can be jumped (if possible in that game). A push button is placed at the top of handle and one push button is placed at the base of handle. Both buttons have same functions. This button is called trigger and usually used for firing or hitting. Light Pen: Light pen is a pointing input device that contains a photo detector or light source, and that allows interaction with a computer through a specially designed monitor. Generally, it is used for engineering designing. Microphone: Now a day, sound capabilities are standard in computers. Microphones are becoming increasingly important input device to record voice/speech. Voice input is used not often where the presentation can benefit from narration. Even if you have a microphone and speaker, you can make telephone calls from your computer. Microphone is also useful to arrange audio conferences through Internet. Digital Camera: A digital camera is another hand-held, portable input device that takes pictures as input. Normal cameras capture pictures on a special coated film; while digital camera captures images electronically without the need of a film. The camera stores the snapshots in its memory then user can copy them into a computer. These images can be edited, printed or copied in a document, etc.