Computers have radically changed the way we live today. 

They are used at work, schools, homes etc, to acquire information, play games, surf the internet,  produce documents, and much more. 

One key aspect of a computer is a Keyboard

The keyboard enables the user to interact with the computer by allowing them to type letters, numbers and other symbols (also known as characters).

But, is a keyboard an input or output device?

A keyboard is an input device. The keyboard captures information in the form of physical keystrokes, and sends it to a computer. The main reason that a keyboard is an input device is that the flow of information works its way from the outside world ‘inward’ towards the computer. 

I shall explain in more detail in this article why a keyboard is an input device. 

What is input and output device

To better understand why a keyboard is an input device, it will help to understand both Inputs and Outputs and see what the main differences between them are.

Input devices

An electronic system will usually include a processor at the center of its operation.

This processor can be a Microcontroller or a Microprocessor depending on the needs, and complexity of the application. 

It is responsible for ‘processing’ information. 

In this case, the processor is onboard the computer’s motherboard, which is essentially the brain of the computing system. 

This information can be generated internally by the processor itself, or the information can be received via Inputs.

The reason for being called an input is because information, or power is entering the system. This can be best visualised by the diagram below.

An input device’s main job is reacting to changes in the environment or physical responses by a user which could be as simple as a button press.

The processor can then deal with the information as required.

A note to be made is that embedded systems are usually where you would find a Microcontroller or Microprocessor being used as the processing unit. 

However, an input can also be part of a non-embedded system, which can be void of a microcontroller or microprocessor. 

For example, a flashlight is a simple circuit that does not include a processing unit but includes an input like a button.

There are many different types of input devices available that provide different functionalities in different circuit setups. 

Below is a list of some of the many;

  • Buttons
    • Mouse
    • Keyboard
  • Switches
  • Sensors
    • Temperature
    • Humidity
    • Light
    • Colour
  • Microphones
  • Potentiometers
  • Light Dependent Resistors (LDR’s)

Below are some common applications that use these input devices;

  • Computing (Mouse, Keyboard, Webcam etc)
  • Mobile phones (Keypad, Capacitive touch screen)
  • Automobile (buttons)
  • Entertainment systems (buttons, switches, potentiometers)
  • Weather stations (Temperature and Humidity sensors)

Output devices

So, we have seen one half of an electronic system,where information enters it through means of power and information via physical changes in the environment also known as the Input. 

The second half of the system is an Output

An output can be best described as information or power leaving the system which can be visualised by the diagram below.

Once the information has been processed by the processor, it can then be sent out of the system into the real world via an output device. 

An example would be displaying information on an Liquid Crystal Display (LCD).

Just like an input, outputs can be part of non-embedded systems as well. 

Going back to the flashlight example, when the button (input) is pressed by the user, a light turns on. The light here is the output of this simple electronic system. 

Below is a list of common outputs;

  • Motors
    • Servo
    • Stepper
    • Vibration 
  • Buzzers
  • Speakers
  • Displays
  • Lighting
    • Light Emitting Diodes
    • Light Bulbs
    • Electroluminescent wire 
  • Printers

Below are some common applications that use these output devices;

  • Audio systems (Speakers)
  • Entertainment (Displays)
  • Computing (Printers)
  • Interior decorating (LED, Light bulbs)
  • Mobile phone (Vibration Motors)

Why a keyboard is an input device and not an output

So, now we know the roles of an input as well an output device, we can dive into why a keyboard is an input device and not an output.

As we saw in the flow diagram of input devices, information is sent from the input to the processor.

The keyboard is a device that captures information and sends it to the processor (in this instance a computer). 

It converts physical keystrokes (via button presses) into digital data which is then sent to a computer for processing. 

The flow of information starts from outside of the processing unit, and makes its way toward the computer as we saw earlier with the flow diagram of input devices. 

How a keyboard works as an input device

Let’s take a closer look at how the keyboard is able to send information to a computer as an input device.

The main reason that it is called a keyboard is that it has ‘Keys’ which are essentially push buttons (or mechanical switches).

When one of the keys is pressed, it closes a circuit which sends a signal to the Central Processing Unit (CPU) of the computer. 

Each key has a specific character (number, letter, or symbol) assigned to it. So every signal sent to the CPU links to that particular key. 

For example if you press the key that displays ‘A’, the signal for the character ‘A’ is sent to the computer which then displays it on screen. 

Certain keys have special functions that allow them to be used with other keys to perform shortcuts (CTRL, ALT, SHIFT), or control direction (UP, DOWN, LEFT, RIGHT).

These can sometimes come in handy when the Mouse stops working, making it hard to navigate. The special keys of the keyboard can be used to navigate instead. 

Where can a keyboard be used as an input device?

While a keyboard is synonymous with a computer, it can also be used with other devices too. 

If you use your mobile phone to type long documents, or even play games, you can now use a keyboard to make the task easier, thanks to the emergence of bluetooth keyboards.

Also, keyboards are being used with Smart TVs to make navigation a lot easier. Instead of pointing a remote at keys on screen to enter search queries, you can use a keyboard instead. 

How does a keyboard get connected as an input to other devices

Connecting a keyboard to a computer as an input  is very simple. It only requires one wire to do so.

The type of wire it uses is a Universal Serial Bus (USB) cable. 

USB is a type protocol for connection, communication and power supply, which is specified for cables and connectors.

These cables are used for computers, peripherals and other other computers. 

So, the keyboard can get connected to a computer and communicate with it while also being powered, with one cable!

But, sometimes cables can be quite annoying! They get in the way and limit how far you can place the keyboard away from the computer.

Bluetooth keyboards are a type of keyboard that does not need a cable to be plugged into a computer. 

It connects and communicates with a parent device (like a computer, mobile phone, smart tv, etc), through the means of Bluetooth protocol. 

What are other input devices similar to a keyboard

A keyboard is only one of the many input devices that sends data to a computer (in the form of keystrokes)

There are many other input devices that provide different types of data to computers through means of  audio, video, image and motion.

Below are some of the most common inputs used in conjunction with a computer;

  • Webcam
  • Mouse
  • Scanner
  • Digital camera
  • Microphone
  • Joystick

What is the purpose of keyboard as an input device in a computer

The main purpose for a keyboard being used as an input to a computer is to allow the user to type data using the set of characters which include letters, numbers and symbols. 

The purpose for the data could be any number of reasons which could include;

  • Writing an email
  • Programming
  • Chatting with friends
  • Writing an essay
  • Entering queries on a search engine like Google
  • Writing a blog
  • Making a powerpoint

This is not an exhaustive list by any means. There are many more applications.

Other than typing data, the keyboard is used for gaming, with each key having a specific purpose inside a game, whether it be for jumping, throwing something, moving around etc.

Another great thing about the keyboard is that it makes navigating many softwares easier. 

Keyboard Shortcuts are a combination of keys that provide an alternative way to do a specific task that you would normally do with a mouse. 

Rather than having to constantly use your mouse to look for and click on a button within a software, you can do it much quicker by using keyboard shortcuts. 

A prime example of this is if you need to select all the words with a word document. Rather than using your mouse to select and scroll through the whole document, you can use Ctrl + A, which does the same job in a matter of seconds.

Who can use a keyboard as an input device?

Anyone who needs to interact with a computer to type data (or for any other purposes mentioned above), can use a keyboard. 

But what about people with physical disabilities? 

Is there a special type of keyboard to make it easier for them? 

Yes, there are special keyboards designed for people with disabilities. These keyboards are modified in a way that makes the task of typing much easier, like increasing the size of the keys. 

Below are some of the type of keyboards available;

  • IntelliKeys
  • KeyGuards 
  • Compact keyboard 
  • BigKeys
  • KidGlove 

For more information above these keyboards check out this website

Can a keyboard be used as an output device?

No, a keyboard cannot be used as an output device. 

The computer does not send information to the keyboard in any way, but rather receives information from it. 

That’s why it cannot be used as an output device.