Categories, types, and functions of input devices

The computer input devices are used to enter data into a computer from different sources the data is then processed by the computer. Data can be entered by keying, scanning, recording, pointing, touching, and other modes of data entry. Input devices are found in all computing devices.

Input devices are used to enter data either manually or directly into the computer. They can be categorized depending on how they enter data into the computer. The categories include text input, video and audio input, pointing, gaming, and image and graphic input devices.

Functions of computer input devices

The general function of input devices is to input data from different sources for processing. There are many ways that data can be entered into the computer which gives the specific functions of each category of device.

1. Key in text characters to the computer.
2. Capturing images and graphics
3. Recording video and audio data
4. Detecting different types of characters and converting them to editable documents.
5. Playing games
6. Point and draw to the screen and object surface.

5 categories of input devices

Category and type of input devices	Examples of the input devices
Pointing device	Mouse, trackball, light pen, touch pad, touch screen, stylus pen
Text, and character input device	Keyboard, document scanner, bar-code readers, Optical Character Reader (OCR), Optical Mark Reader (OMR), Magnetic Ink Character Reader (MICR)
Image and graphic input	Digital cameras, smartphones
Video and audio input device	Video cameras, microphones, CCTV, and webcams
Gaming input device	Joystick, gamepad

1. Computer input devices for text and character input

They are used for entering special characters and alphanumeric data into the computer. text input hardware includes

1. Bar-code readers: Bar-codes are a set of lines of different thicknesses which are used to represent a number or code. They are mostly used to identify consumer goods. Barcode readers are used to reading the coded line to translate them into numbers and input them into the computer.
2. Keyboard: It has keys, similar to a typewriter and it is used to key in the characters into the computer. Different keys are used for different functions. The main type of keyboard is a QWERTY keyboard which is gotten from the arrangement of keys.
3. Optical Character Reader (OCR): it is a system that includes a scanner and software that are used to convert handwritten characters into digital data. They scan the document and identify different characters then make them editable.
4. Optical Mark Reader (OMR): they are used to identify marks made by pencil or pen. OMR is used to mark multiple-choice questions that are specifically marked.
5. Magnetic Ink Reader (MIR): they are used to read characters created by magnetic material. Mostly they are used to read cheque numbers.

2. Video and audio category of the input device

Audio input device

1. Microphones: They are connected to the sound port that is either on the front or back side of the computer. Microphones are used to input sound data into the computer by converting it to digital signals which are processed by digital computers. They can be separate microphones or a headphone that incorporate microphones. They are also used in voice recognition and giving voice commands to the computer for the visually impaired.

Video input device 

They help input moving image data. The main devices include

1. Digital video cameras: They are used to capture both still and moving images which can later be transferred to the computer. They have an SD memory where videos are stored when captured.
2. Closed-Circuit Television (CCTVs): These are types of digital video cameras that are mainly used for security surveillance. CCTV records video in real time and can be connected to a control room where a person can monitor it. They are used for company, home, street, and building security surveillance.
3. Webcams: They are digital video cameras that are mainly used when users are online for meetings and video conferences. Most cameras that come with laptops are meant to be used as webcams. Users can also buy an external webcam that can be connected to the computer by a USB connector.

3. Pointing devices category

They are used to move the cursor on the screen to the specific point that the user requires. They include

1. Mouse: It is the most common pointing device in desktop computers. It has two buttons on each side right and left buttons and for old types, they have a wheel in the middle. Users click on either button to invoke a command.
2. Trackball: It works similarly to an old mechanical mouse, but the ball is on the top side which is moved with a thumb. When the thumb moves the ball it moves the cursor on the computer screen. It reduces hand movement since only the thumb is required to move the cursor.
3. Touchpad: It`s mostly used in laptops and it`s an alternative to the mouse. It is mostly fixed on the laptop and it can be controlled by a single finger. The right and left buttons are provided on the side of the pad to be used for the same function as those of a mouse.
4. Light pens: They are used to write on the computer screen which is sensitive to touch. They are used to draw on the screen, write text, or even select data on a computer screen.
5. Touchscreens panels: They are computer or smartphone screens that are sensitive to touch. They respond when touched by either finger or other objects depending on the technology used to design them. They can be used to input and control many functions of a device.

4. Gaming input devices

1. Joystick: It is a stick-like device that is used to control the movement of the cursor on the monitor so as to make a move in the game. As you move it there is an equivalent move on the game you are playing.
2. Game-pad. They are pads that are used to play games and have controls to reset and a direction button to be used to make a move on the game.

5. Image and graphic input devices.

1. Scanners: They are used to convert text and or graphics by scanning to make digital images that can be edited. They can scan to produce a black-and-white image or colour depending on the feature of the scanner. There are two main scanners flatbed and handheld.
2. Digital cameras: are used to capture still images which are later transferred to the computer. They work like digital video cameras it’s only that they don`t take moving images. Images are stored on a memory stick before being transferred.
3. Smartphone cameras: all the latest smartphones have high-quality cameras that can be used to capture both video and pictures.