Input devices are devices used to capture data into the computer.

They are devices used to send data to the computer.

Input devices convert our commands and data to a form that the computer can understand. 

As the computer can only understand data that comes from the input devices, input devices are necessary to get data to the CPU for processing.

Due to continual research in computer hardware, we have a large number of input devices.

I will introduce a variety of input devices in today's post.


The keyboard is probably the most important input device. It is used to enter a command into the computer system. 

The keyboard allows instructions and data to be entered into the computer through the use of a variety of keys.

The keyboard contains alphanumeric keys, function keys, special keys, and other keys used to type instructions that direct the computer to perform a specific task. 

Some keyboard now comes with added keys for using the internet. 


With each press of a key, a character engraved in the key appears on the screen.

To perform some Unique action, one needs to hold multiple keys simultaneously. 

For instance, to save files, one needs to hold the "control" and "S". keys.

The keyboard is an integral part of any information/data processing system.

The keys on a computer keyboard are as follows:

1. Typing keys: These include letter keys (A-Z) and numeric keypads (0-9). They are mostly used for typing documents.

2. Function keys: These are the 12 keys(F1-F12) which are usually at the top of the keyboard. These keys usually serve as shortcuts for performing specific functions. F1, for example, is the default help key In many programs.

3. Special-purpose keys: These are used for specific purposes. Cap lock, Num-lock, and print screen are examples of special-purpose keys.

4. Control keys: These include keys(such as the four directional keys, home, control, and alt) that provide the user with cursor and screen control.

The advantage of using a keyboard is that it allows users to enter data into a document faster.

On the flip side, keyboards are relatively large devices that take up a lot of space.
Additionally, people with limited arm use may find it challenging to use the keyboard.


This is the most popular pointing device. The mouse is a handheld device that controls the cursor in a GUI (graphical user interface).
It is used for moving and selecting texts, icons, files, and folders on the computer. 


It allows users to communicate with the computer through actions such as "point" and "click". 

The mouse allows you to control the movement and direction of the on-screen cursor by moving it on top of a desk.

Pressing a mouse button produces a 'mouse click'. 

Mouse clicks are as follows:

1. Left click: This is usually used to select an item.

2. Right-click: Usually used to display a set of commands.

3. Double click: Computer users use this to start a program and open a file.

The majority of conventional mice have a tiny ball under them that measures the movement direction of the mouse. 

The movement of the ball causes two rollers in the mouse to rotate: the first roller records north-south movement while the other records the east-west movement.

The mouse detects the ball's rotating direction and sends the corresponding signals to the computer to move the pointer.

Many mice now have a scroll button or wheel that allows users to scroll through a document.

Also, recent development has led to the emergence of optical mice and cordless mice.

An optical mouse does not have any moving parts and instead detects movement using reflected light, while a cordless mouse connects to a computer without the use of a wire.

Uses of mouse

1. The mouse is used to open, close, and minimize application windows

2. It is used to control the position of the cursor on the screen

3. The mouse can also be used to move, group, and delete files.

4. The mouse is also useful for image editing, particularly in Adobe Photoshop

5. Mouse is also useful for plotting graphs.

Advantages of mouse

1. When compared to a keyboard, a mouse can be faster at selecting options.

2. A mouse is small and occupies a small amount of space

3. Mouse enables rapid navigation through documents. The mouse, for example, allows you to scroll through documents quickly.

Disadvantages of mouse

1. Mouse is difficult to use when a flat surface is not available. 

2. Similar to the keyboard, people with limited arm use may find it challenging to use a mouse.

3. The mouse is one of the input devices that is easily damaged.

Barcode Scanner

A barcode is an image consisting of a string of parallel black and white lines that transmits information when scanned.

Barcodes are usually read by special optical scanners called barcode scanners.

A barcode scanner is an input device used to capture and read data encoded in a barcode.

Barcode scanners use a beam of light across the barcode, scaling the amount of light that is reflected. 

A preponderance of barcode readers contains decoder circuitry.

This decoder circuitry analyzes the barcode's image data delivered by the sensor and transmits the barcode's content to the scanner.

The dark bars on the barcode will reflect less light than the white spaces between them. 

This scanner then transforms the light energy into electrical energy, which is then converted into data by the decoder.

Optical Mark Recognition(OMR)

Optical Mark Recognition or reader (OMR) is used for capturing human-marked data from documents. 

It is the technique of electronically extracting data from marked fields on printed forms.

It is used to scan and read multiple-choice examination papers in the form of a shaded line. OMR allows for hundreds of documents to be processed within an hour. 

OMRs are also used for surveying, balloting, and questionnaires.

The utilization of a "bubble sheet" for multiple-choice tests by schools is a common application of OMR technology.

The student indicates his answer by filling in the corresponding bubble in the OMR sheet.

Once the form had been completed, the teacher would check the answer using an OMR.

Optical Character Reader (OCR)

This is an input device that converts text in a scanned or photoed image into text that may be stored and edited electronically.

It is an electronic process that produces a machine-readable version of a printed, typed or handwritten document. 

OCRs are a conventional method of digitizing printed texts so that they can be edited and stored conveniently.

OCR is very useful for processing information in large volumes of documents.

Businesses specializing in digitizing data gathered from photographs or documents into an electronic system make use of OCR.

Magnetic ink character recognition (MICR)

MICR is a type of input device used primarily by banks to facilitate the processing and clearance of checks and other documents.

MICR is a technology that allows MICR readers to scan and read the data directly into a data-collection device. 

MICR enables banks to read the numbers or signals on the bottom of checks or deposit slips, which are often recorded using special magnetic ink.

Unlike a barcode, MICR characters can be read easily by humans.

MICR encoded documents can be processed much faster than traditional OCR encoded documents.

A MICR can scans characters printed in a unique magnetic ink into the computer.  

MICR is mostly utilized by banks as there are a large number of cheques to be processed.

MICR readers can only read one special font which can depict a few punctuation marks and numbers.

It can scan many characters instantaneously. 

Information printed in magnetic ink is secured since it can not be modified or rewritten with a pen. 

Furthermore, squeezing cheques ( which is a common practice) does not damage the printed number on the cheque.

However, both the MICR reader and the special inks are relatively expensive. 

Advantages of MICR

1. MICR offers greater security than OCR because the printed character cannot be easily altered.

2. They can be read even if someone writes over the magnetic strips

3. Errors are reduced because there is no manual input.

Disadvantages of MICR

1. As earlier noted, MICR is very expensive as both the MICR reader and the special inks are relatively expensive. 

2. The number of characters that a magnetic ink character recognition system can read is very limited.

Light Pen

This is a pointing device similar to a pen. It is the wand used in conjunction with a cathode ray tube (CRT) display to point at displayed objects or draw on the screen.

Light pens are light-sensitive and provide a very precise pointing capability. 

Light pens are generally used to select or modify text, and data on a screen.

A light pen is mostly used by Computer-Aided Designer(CAD) users to draw on the screen.

When a light pen is scanned by a cathode-ray tube electron beam, it recognizes changes in the brightness of nearby screen pixels and transmits the timing of this event to the computer. 

The computer keeps track of the expected time of scanned locations on the screen by the beam and infers the pen's position from the latest timestamp.


This is like an upside-down mouse with the ball on top.

Trackballs are formerly used in laptops and notebooks computers, but, they have been replaced with touch balls.

The pointer on the screen moves whenever you turn the ball with your hand. It has buttons like a mouse. 

Trackball requires very little space to operate. It is constantly used with computer-aided design(CAD). 

Advantages of trackballs

1.  They do not require the same fine control as a mouse 

2. A trackball is easier to use than a mouse for people who have limited arm use.

3. Trackballs take up very little space as they are stationary

Disadvantages of trackballs

1. Unlike a mouse that is supplied with a standard computer, a trackball is not supplied with a standard computer. Plus, they can be very expensive to get.

2. Because they are not common, users may need to learn how to operate them.


This is similar to a tracker ball in operation. The only difference is that you have a vertical stick that is moved rather than a rolling ball.

The stick moves the graphic cursor. Most joysticks usually have a button on top of them that is used for gaming purposes.

Joysticks are mostly used to play computer games. It usually has several buttons that can be pressed to trigger actions.

Whenever you pull the joystick, it tells the computer the direction in which it is being pulled. This information is then used (for example) to move a car on the screen.

However, controlling the on-screen pointer using a joystick might be tricky when compared to other pointing devices.

Digital camera

This is an input device that used digital technology to capture images and videos.

After taking images and saving them in the digital camera's memory, they are transferred to the computer system through USB.

Once transferred to the computer system, the image can then be edited and utilized for various uses.

Digital cameras, unlike traditional cameras that utilize film to capture photos, use an image sensor chip to capture the image.

Digital cameras are now becoming more popular than film-based cameras. 

Advantages of Digital camera

1. Producing higher-quality images is easier with a digital camera than with a traditional camera.

2. Digital cameras allow storage to be reused because images can be deleted and new images can be taken to fill the void.

Disadvantages of digital camera 

1. The users have to be taught before they can edit the images on the computer.

2. An excessive amount of image transfer to a computer may cause the computer to run out of storage.

3. Digital cameras can be expensive to maintain because they consume a lot of batteries.

4. Images and video stored in the digital camera could be lost if the device malfunctions or files are corrupted while transferring files.


This is a digital video camera without a memory card.

Webcams (or web cameras) are connected directly to the computer through USB and the information the webcams sees is transmitted live to the computer system.

Webcams are thus considered input devices because they capture data in the form of digital video and transfer it to the computer

However, due to technological advances, some computers now possess built-in webcams

Uses of Webcam

1. it can be used to communicate with family and friends over the internet in real time.

2. It is used for video conferencing. A meeting to be held on zoom, for example, may require you to switch on your webcam.

3. Webcam is used for security surveillance. Many organizations have webcam place in a strategic position to monitor events within their premises 

4. Webcams have educational applications as well.

They're currently being used to administer online tests to students

Advantages of webcam

1. It can be switched on and off at any time allowing for flexibility.

2. It allows people who are thousands of miles apart to have a live conversation with each other and see what each other is doing right now.

Disadvantages of webcam

1. Webcam must be connected to a computer to be fully functional.

2. Webcams are limited in terms of features because they are heavily reliant on the processor and operating system of the computer system to which they are connected.


This can be used to input sound into the computer.

A microphone converts sound waves into audio signals, which are then converted to digital audio data and sent to the computer.

The microphone is directly connected to the computer system so that sound can be inputted and manipulated

Uses of microphone

1. It is used to insert sound into the computer.

2. It is used to send voice commands. For example, one can use a microphone to insert instructions into Google to search for information.

3. You can use a microphone to add sound to your presentations.

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Advantages of microphone

1. Reading texts over a microphone is easier than typing them on a keyboard. More so, Voice recordings can be easily converted into text for use in a word process text-to-speech to-speech technologies

2. A microphone is more secure than passwords when used for voice activation

Disadvantages of microphones.

1. Although, not as much as video files, sound files also take up space in the computer storage.

They can create storage issues in a computer if not managed properly.

2. The use of a microphone as an input device is limited because voice recognition software isn't as accurate as typing on a keyboard.


As discussed in this post, the twelve input devices are a keyboard, mouse, bar code scanner, MICR, OCR, microphones, trackball, joysticks, webcams, digital camera, OMR and Light pen.

I did my best to describe each of these input devices as precisely as possible. However, if you have any questions or recommendations, please leave them in the comments section.

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