3.1+IO+Keyboards,+Mice+and+Touch+Pads


 * __Input & Output Devices __

__Hardware __ __Keyboards __ A computer keyboard is an input device used to enter textual information into a computer system. Computer keyboards contain many different characters to suit different languages or dialects, as tool for means of communication, it is very useful. The key board functions by means of electrical system. Each key compresses an electrical switch, which closes an electrical circuit. This generates a keystroke signal, which is processed by the keyboard's onboard processing chip. This chip then converts the keystroke into a code which is transmitted to the computer system, displaying the button character in response.

__Mice __ There are two different types of computer mice: The motion of the two rollers is converted into electrical signals which are then sent to the computer through a cord. The software on the computer then converts these electrical signals into meaningful X and Y movement of the mouse cursor that you see onscreen.
 * ** Mechanical ** – The first developed mouse, (was also known as a ball mouse), uses a ball to work. The ball allows the mouse to smoothly move across a surface. Inside the mouse are two rollers that roll against two sides of the moving ball. One roller tracks the horizontal motion of the mouse, and the other roller tracks the vertical motion.
 * ** Optical Mice ** - The most common computer mice in use today. An optical computer mouse works using optical technology and so don't require any moving parts. As you move an optical mouse over a surface, a small red LED (**L**ight-**E**mitting **D**iode), it emits a light onto a surface and reads the pattern or grid on that surface. The mouse converts this surface information into meaningful motion data which is sent to the computer.

** Sources ** : http://www.build-gaming-computers.com/computer-mouse-work.html

__Touch Pads __ Input devices that allow the user to use multi-finger or multi-hand gestures to accomplish complex tasks quickly. A multi-touch device might be a touch-sensitive screen, a touch tablet, or a trackpad that can recognize the position, pressure and movement of a more than one finger or hand at a time. One of the best known examples of a device with a multi-touch input device is the Apple's iPhone. Apple have produced many applications to callaborate with the design of the iPhone, ultimately requiring different hand movements and gestures. List of commonly known touch pad devices:
 * iPad
 * Samsung Galaxy Pad
 * Hp Touchpad
 * SMART boards