The Keyboard

The part of the computer that we come into most contact with is probably the piece that we think about the least. But the keyboard is an amazing piece of technology. The keyboard on a typical computer system is actually a computer itself.  

A keyboard is a series of switches connected to a microprocessor that monitors the state of each switch and initiates a specific response to a change in that state.  The processor in a keyboard has to understand several things that are important to the utility of the keyboard, such as the position of the key on the keyboard, the length of time the key is held and the number of times that a key is struck. 

In all keyboards each circuit is broken at the point below a specific key. Pressing the key bridges the gap in the circuit, allowing a tiny amount of current to flow through. The processor monitors the position of that key  on the grid. When it finds a circuit that is closed, it compares the location of that circuit on the grid to its own map. The  map is basically a comparison chart for the processor that tells it what the key at x,y coordinates on the keyboard represents. If more than one key is pressed at the same time, the processor checks to see if that combination of keys has a special function. For example, pressing the a key by itself would result in a small letter "a" being sent to the computer. If you press and hold down the Shift key while pressing the a key, the processor compares that combination with the character map and produces a capital letter "A."

The materials used in a keyboard are conductors like copper, which when circuits are closed carry current to the micro processor.  The face of a keyboard is made up of plastics. Plastics are chosen because they are good insulators, are inexpensive and withstand wear well.

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