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An idea for a keyboard layout and how it interacts with the computer

arabysoft705@gmail.comOctober 10, 2024

0 0 8 minutes read

An idea for a keyboard layout and how it interacts with the computer

It is often the part we use most that we think least about. But you should know that the keyboard is an amazing piece of technology. For example, did you know that the keyboard in the standard computer system is a computer in itself? Inside the keyboard, you will find a set of key switches connected to a small microprocessor, which monitors and determines the state of each key and provides a specific response to changes in this state. In this post, you will learn more about these keys, how they work, the types of keyboards, and how they interact with the computer, among other things.

Types of Keyboards

The keyboard has not changed much, but the most notable changes to it are the natural developments to add new keys to provide the keyboard with new functions. The most common types of keyboards are as follows:

101-key Enhanced keyboard
104-key Windows keyboard
82-key Apple standard keyboard
108-key Apple Extended keyboard

Laptops often have a unique and specific keyboard layout for the device, and many keyboard developers add additional keys for specific functions. Generally, the keyboard consists of these main types of keys:

Typing keys
Numeric keypad
Function Keys
Control Keys

The printing keys are the part of the keyboard that contains letters and symbols and usually have a uniform shape known as QWERTY, referring to the first 6 letters of the English keyboard, designed in this way to slow down fast typists by making the letter arrangement somewhat strange. The reason makers of typewriters wanted to slow down typing speed was that the mechanical arms used to type letters on paper would collide and get closer together if typed too quickly. Despite the mechanical arms no longer being a problem, the design of the QWERTY layout is still used in computer keyboards. As a result of criticism of this keyboard layout, a new arrangement of keys inside the keyboard, called DVORAK, was developed to make typing easier, more comfortable, and less likely to result in the aches associated with long-term typing. However, it has not been widely adopted yet.

The numeric keys are a natural development of the keyboard layout due to increased computer usage in many tasks, and as numbers are a type of information, 17 keys were added to the keyboard for numeric input. In 1986, function and control keys were added to the keyboard layout to give specific commands to the open application or the operating system. The function keys are arranged in a single horizontal row above the main keyboard to provide specific commands to the running application or operating system, while the control keys provide more flexibility for controlling the cursor and displayed screen. There are four keys organized in a T shape between the typing keys and the numeric keypad that allow for smooth cursor movement on the screen and enable the user to make significant jumps in most programs and applications. Some of the important control keys include End, Insert, Delete, Page Up, Page Down, Ctrl (Control), Alt (Alternate), and Esc (Escape).

Table of Contents

Inside the Keyboard

The processor must understand many things and commands required for using the keyboard, such as:

Key Matrix location
Amount of pressure and how it is classified and categorized
The speed at which the keys are pressed

Key Matrix

The Key Matrix is a network of circuits beneath the keys, and in all types of keyboards except Capacitive Keyboards, each circuit is open below the specific key. When the key is pressed, a bridge is connected between the circuit terminals, allowing a small amount of electric current to flow at that point. The processor monitors the Key Matrix to detect if a circuit has been closed and then compares the position of this circuit to the Character map stored in its ROM memory. The Character Map is a comparison chart between the circuits and the response of the Key Matrix to these circuits and the characters they represent to inform the processor which letter was pressed. Thus, the Key Matrix is responsible for the sudden change in the circuits below the keys due to pressing the keys. The Character Map translates these changes to the processor to understand which letter was pressed. Meanwhile, if the Character Map sends a set of letters, the processor compares them in the Character Map and then sends the letter to the computer, transforming it. For example, when you press the “a” key, it sends it to the computer as “a,” and when you press Shift + “a,” the processor compares this combination in the Character Map and sends it to the computer as “A.”

The keyboard relies on the keys that cause a change in the electrical current flowing through the circuits beneath the keys. When the key is pressed towards the electric circuit, there is usually a small amount of vibration between the surfaces, known as bounce.

The processor recognizes the fast movement of the ON and OFF in the electric circuit as you keep pressing the key continuously. It understands that you want to repeat this letter every time you press a specific key, so it sends it repeatedly to the computer to display it on the screen. This is known as Typematics, and the delay between each letter and the next one can be adjusted through the device’s software, typically allowing about 30 repeated letters per second.

Keyboard Technology

It is worth noting that the keyboard has many technologically advanced features, and it is fascinating how we enjoy the tactile and audible response of pressing the keys. Let’s talk about some of these amazing technologies of the keyboard:

1- Rubber dome mechanical

This type of technology is widely used in keyboards. In this type, each key has a flexible rubber dome with a solid carbon center. When you press the key, there is a plunger or compressor below the key that pushes down towards the rubber dome, causing the carbon part in the center of the rubber dome to press downward as well, pressing the carbon part to a flat surface beneath the key matrix. As long as you keep pressing the key, the carbon in the center continues to close the electric circuit at the key’s position in the key matrix. Once you release the key, the rubber dome returns to its original position, causing the key you pressed to return to its resting state before you pressed it.

This type of technology is not expensive, provides good tactile and audible response to the keys, and can resist rust due to the rubber layer covering the key matrix.

2- Membrane mechanical

This type is similar to the previous one but does not have isolated keys like the previous type. Instead, it has a rubber membrane with a certain protrusion for each key. You may have seen this type of key in devices designed for heavy industries because most of them offer tactile response, in addition to being difficult to maneuver, which is why this type is rare to find in traditional computers.

3- Capacitive non-mechanical

This type is non-mechanical as it does not work mechanically since it does not close a circuit like other types. Instead, the electric current flows continuously through parts of the key matrix. Each key has a very small layer connected to the bottom of the key’s compressor or actuator, and when you press the key, the layer at the bottom of the key approaches directly to the layer below it. Because the two layers get closer, the amount of electric current flowing through the proximity point is affected, and the processor detects this change and determines the key’s location where this change occurred.

This type of technology is expensive but has a longer lifespan than other types, is resistant to rust, and has fewer issues that may arise from the surfaces meeting together as in the first type.

4- Metal contact mechanical

This type is not commonly used and rarely found. It simply has a metal part beneath the compressor below the key, and when you press the key, this metal part connects the circuit terminals, allowing the processor to detect this change. This type is not expensive, provides tactile and audible response to the keypresses, but is more prone to rust due to the metal part, and there is no barrier to prevent dust and water from reaching the circuits inside the keyboard.

5- Foam element mechanical

It closely resembles the previous type in many characteristics, such as susceptibility to rust, cost-effectiveness, tactile and audible response to the keys, and inability to block dust and water from entering the circuits inside it. However, instead of the foam part spongy foam between the actuator below the key and the metal part.

From Keyboard to Computer

As you type, the processor analyzes the Key Matrix and determines the letters to be sent to the computer, saving this information in a buffer memory of approximately 16 bytes and then sending this information to the computer through certain types of connectors.

The most common types of connectors between the keyboard and computer are as follows:

5-pin DIN (Deustche Industrie Norm) connector
6-pin IBM PS/2 mini-DIN connector
4-pin USB (Universal Serial Bus) connector
internal connector (for laptops)

Regular DIN connections are rarely used nowadays, but most computers use the mini-DIN PS/2, and with the rise of new systems, most have switched to USB connectors instead of the older connectors.

It does not matter which type of connector is used, but what matters is that there are two elements passing through these connectors. The first element is the power or electricity supplied to the keyboard. The keyboard requires a small amount of electricity, approximately 5 volts, and the cable carries another element, which is the data, from the keyboard to the computer. One end of the cable is connected to the keyboard, and the other end is connected to a port on the computer, which is an integrated circuit (IC) that processes all the data coming from the keyboard and presents it to the operating system. When the operating system notices that there is data coming from the keyboard, many things can happen:

The operating system checks if this data is a command for the operating system itself, such as Ctrl-Alt-Delete in Windows, which is a command specific to the operating system and opens a menu to choose from several options to shut down your computer, open the task manager, or other actions.
The operating system passes this data to the current program or application.
The current application understands the data coming from the keyboard as commands specific to the current application. For example, Alt-F to open the File menu in the application or Alt-F4 (FUNCTION KEY) to close the application.
The current application may accept the incoming data from the keyboard as content and a command within the application. Or the application may not accept the incoming data and therefore ignore it.

If the data coming from the keyboard is processed as operating system commands or commands for the current application, the processing method for both cases is the same. The amazing thing about all of this is how it happens so quickly – there is no time lag between my fingers pressing the keys and the letters appearing on the screen in front of me. When you think about everything the computer does to show you every letter as you type, you’ll find that it’s simply unbelievable. That’s what prompted me to write and share this post with you. Thank you.

arabysoft705@gmail.comOctober 10, 2024

0 0 8 minutes read