How A Keyboard Works?

There are many various types of keyboards; they are mainly distinguished on the basis of the switch technology they use. Seeing that there are so many switches required, and on the basis of their reliability level a keyboards is defined.

The selection of switch technology influences the key response; better and newer versions have been using better technologies to achieve superior cost savings. Some types of keyboards include Dome-switch Keyboard, Capacitive Keyboard, Mechanical-switch Keyboard, Buckling Spring Keyboard, Hall-effect Keyboard, Laser Keyboard, Membrane Keyboard, Roll-up Keyboard, Waterproof Keyboard etc.

The Dome-switch keyboards are basically a hybrid type of membrane and mechanical keyboard. The Capacitive keyboard modifies the capacitance of an outline printed on a PC board. The Mechanical-Switch keyboard basically uses real switches, with a format of one under each key. These are some common attributes of modern keyboards.

Every key is a single switch. It has two electrical contacts that are short when key is pressed. Silicone dome or metal spring returns the key mechanism and remains it in upper position.
Contacts are connected with 20 wires, just like 10 x 10 nodes in square fishnet. This is done so because 100 wires would be too extensive. Of course, their real, physical lauout is different.

The 10 "row" wires are subsequently feed by electric pulse, while the other 10 "column" wires are "listen" for response.

When a key is pressed that is connected to row 4 and column 7, the response occurs only on  column 7 in a moment when row 4 is feed.

Keyboard chip cleans the signals up to eliminate vibrations and non-sure contact events. Next, it communicates with cable, infrared od Bluetooth and sends these "key codes" (47 in our example) to computer.