Keyboard is one of the types of input devices of the oldest and has long been a complete computer system device. The keyboard itself is a form of input device consists of a board that the buttons sign letters and numbers and functions (F1, F2, … F12). If the order to be seen a glimpse of the typewriter. The buttons are arranged in such a way that can be used to enter (input), such as data and commands on the computer system.
Attendance at this keyboard is also equipped with other types of input device called a mouse. Practice with a video display or monitor also called as the output device, interaction between people with computers can be done.
Keyboard divided into two types, namely type mechanical switch array type structure and a flat layer 3. In the mechanical type switch array, an array of mechanical switch mounted on the printed-circuit board, where the switch is arranged in rows and columns that are connected to the micro-controller on board. At the time a switch is pressed, the controller will be identified and then the column so that the key is pressed.
While in the type structure of the flat layer 3, the top layer consists of a plasticized layer position with the key shown on the top surface and Conducting trace stored on the bottom. Second layer made of rubber with a hole in the key position. While the third layer is metallic down to the protrusion at the position of the button. At the time the button is pressed, then the trace underneath will protrusion in contact with the base layer to form electrical circuits. Fold the flow of electrical circuits will be received micro-controller. This type with the keyboard allows the emphasis of production and cost advantages of the side because it is resistant to the problems of food and liquid spillage. An example is the keyboard type terminal point-of-sale.