Input Devices

What are input devices?

The devices that are used to input or feed data into the computer are called as input devices.

What are the types of input devices?

There are 5 types of input devices:

  1. Input pointing devices
  2. Input audio-visual devices
  3. Input reading text
  4. Input card readers
  5. Input sensors
  6. Input remote control

What are input pointing devices?

The devices that are used as pointers on a computer screen to input data into the computer are called as input pointing devices.

What are the examples of input pointing devices?

Here are some examples of input pointing devices with their advantages and disadvantages:

  • Mouse
    • A mouse is a pointing device found on most of the personal computers
    • Sensors on the bottom of the mouse detect the change in movement
    • Data regarding this movement is sent to the computer, which immediately responds by moving the cursor on the computer screen.
    • Advantages of using a computer mouse:
      • Enables rapid navigation through an application such as a web browser
      • Requires a small area on the computer to use
    • Disadvantages of using a computer mouse:
      • Challenging to use if the user has limited wrist or finger movement
      • Needs a flat surface and a mouse-pad to move and function
    • Touch Pad
      • Touch pads are pointing devices found on most laptop computers
      • It has an advantage over the use of mouse as touch pads are inbuilt into the laptop and consume less space
      • A touch pad functions when the user moves his/her finger across the pad
      • This movement is detected and sent to the computer
      • The computer responds by moving the cursor across the screen.
      • Touch pads are commonly used as pointing devices in graphic user interfaces (GUI)
      • Advantages of using touch pads:
        • There is no extra device to buy and carry; touch pads are inbuilt into the computer
        • Generally, touch pads are easier to use than a mouse
        • Touch pads are also faster to navigate through applications
        • They consume far less space and are compact.
      • Disadvantages of using a touch pad:
        • Challenging to use if the user has limited wrist or finger movement
        • Controlling the pointer is challenging, as compared to using a computer mouse
        • Touch pads are difficult to use for actions such as dragging, drawing and rotating
        • Touch pads tend to be used in cramped conditions; this can lead to numerous health issues.
      • Trackerballs
        • Trackerballs aren’t moved like a mouse; instead, they have a large ball that the user spins to navigate through the computer screens
        • Trackerballs are specially used by people with limited hand/wrist movement as they are easier to use as compared to a computer mouse
        • Some mobile phones also make use of trackerballs for faster navigation.
        • Advantages of using a trackerball:
          • Easier to use than a mouse, if the user has limited wrist/ finger movement
          • Trackerballs allow faster navigation as compared to a computer mouse.
        • Disadvantages of using a trackerball:
          • Trackerballs cost more as they aren’t normally included with a computer and need to be bought separately
          • Time is required to get accustomed to use a trackerball
        • Touch screen
          • A touch screen is an effective alternative to a separate pointing device such as a computer mouse
          • With touch screen, the user selects items on the computer screen by pressing on the surface
          • This makes touch screen system interesting, interactive and easy to use
          • Touch screens are often used at information terminals and public places such as libraries, railway stations, ticket terminals, self check in terminals at airports, etc.
          • Advantages of using a touch screen:
            • Easier to use
            • Cannot be stolen
            • Interactive
            • Difficult tasks such as rotating the screen can be easily executed with touch screen
          • Disadvantages of using a touch screen:
            • Touch screens are extremely expensive to purchase
            • Touch screens can be damaged by scratches and rigid finger impressions
          • Graphic tablets
            • Graphic tablets are pointing devices that are specially meant to be used by designers and artists
            • They allow natural hand movement to be input into graphic applications
            • Graphic tablets use a stylus to be moved over the tablet’s surface
            • Data regarding this movement is sent to the computer and is executed in graphic applications
            • There is a major advantage as the stylus supports hand drawn images and sketches to be drawn.
            • Advantages of using graphic tablets:
              • Easy to create hand drawn sketches
              • Extremely portable
              • Promotes natural wrist movement
            • Disadvantages of using graphic tablets:
              • Graphic tablets are more expensive than other pointing devices
              • They can easily get damaged if not handled with care.
            • Joystick:
              • Joysticks are popularly used for playing games
              • The user needs to move the joystick in the required direction
              • Information regarding this movement is sent to the computer, which immediately executes the action by showing appropriate movement over the computer screen
              • Modern mobile phones also have small joysticks to allow users to navigate rapidly across the computer screen.
              • Advantages of using joysticks:
                • Extremely fast navigation
                • Joysticks are sensitive to the slightest move; this enhances the user’s gaming experience
                • Joysticks are extremely handy; this again enhances user gaming experience.
              • Disadvantages of using joysticks:
                • Joysticks tend to be costlier than other pointing devices
              • Light pen:
                • Light pen is a device used as a pointing device or to write on a computer screen
                • Light pens are rarely used as high quality touch screens and graphic tablets provide similar and better functionality.

What are input audio-visual devices?

Devices that use audio and video to input information into the computer are known as input audio-visual devices.

What are the examples of input audio-visual devices?

  • Scanner
    • A scanner is an input device which scans images.
    • Basically, scanning is simply taking a close-up photograph of an image.
    • The scanned image data is passed to the computer and used by the users.
    • The most common type of scanner is a flat-bed scanned which has a glass plate on which the item to be scanned is placed.
    • The item is illuminated and an image of it is captured by a moving scan head.
    • Scanned images can be further processed once inside the computer.
    • Advantages of using a scanner:
      • Can be used with other softwares to improve or repair photographs
      • Scanning is the only way of digitizing old paper-based images
      • A scanner can be used in conjunction with special Optical Character Recognition software (OCR) to scan and enter text into a word processing document instead of typing.
    • Disadvantages of using a scanner:
      • Scanners take up a lot of space
      • The quality of the scanned item may be poor, depending on the scanner’s resolution.
      • It can take a lot of time to digitize all the pages in a lengthy document
      • They aren’t portable
    • Digital camera
      • A digital camera is a device that captures digital photographs.
      • Most digital cameras don’t directly input data or photographs into the computer; they store photographs on memory cards and then can be transferred onto a computer.
      • A modern digital camera can capture photographs of 10 megapixels or more per photograph! This means 100,000,000 pixels in every snapshot!
      • Advantages of using a digital camera:
        • No need to use chemicals while developing films
        • The images are in a form that can be directly placed in a word document or in a presentation
        • The digital images they produce can be easily sent from place to place using social networking websites, e-mail etc.
      • Disadvantages of using a digital camera:
        • The photographs may not be of good quality as compared to photographs produced using chemicals.
        • A photographer needs to have professional skills to use digital photographs and edit them
      • Video camera
        • A device that captures moving images or video is called a video camera
        • Like a digital camera, most video cameras do not directly input data into a computer
        • The captured movies are stored on video tapes or memory cards and then transferred to a computer
        • Advantages of using a video camera:
          • Can capture both- still and moving images
          • Easy to transfer video to computer
          • Can store many images or videos until it can be used for editing
        • Disadvantages of using a video camera:
          • Very difficult to produce good video without training on a video camera
          • A video camera can be expensive to buy
          • Editing a movie on a video camera is complicated
          • Picture quality of the video is determined by the number of pixels and this may be low unless an expensive video camera is purchased.
        • Web Camera
          • This is a very basic video camera used to feed live videos into a computer
          • The video data from a web camera is of low quality as compared to a video camera
          • However, it is good enough for web chats on Skype, Messenger, etc.
          • Usually a web camera is clipped onto the top of the computer screen; however, many laptops now have web cameras built into the edge of the screen.
          • It is mainly used to conduct simple video conferences
          • Advantages of using web camera:
            • We can see the reaction of people as they are talking using a web camera
            • A web camera allows people to view traffic on the local roads
          • Disadvantages of using web camera:
            • Limited extra features to improve image quality
            • The picture quality can be poor at lower resolutions
            • Generally have a fixed position; hence cannot be moved around
          • Microphones
            • A microphone is an input device that converts sound signals into digital signals that can be input into a computer.
            • The signal from a microphone is usually analogue; so before it can be processed by the computer it must be converted into digital data.
            • An ADC (Analogue Digital Converter) is used for this conversion (ADCs are usually built into the computers sound card to do so)
            • Advantages of using a microphone:
              • Microphones can be used by disabled people to input data
              • Microphones are very cheap to purchase
              • It can be faster to speak instructions over a microphone, rather to type them
            • Disadvantages of using a microphone:
              • Background noises can cause problems while using voice recognition system with a microphone
              • Voice recognition is not completely accurate; hence mistakes may occur
              • Sound files when stored, take up a lot of disc space

What are input reading text devices?

MICR (Magnetic Ink Character Reader)

  • MICR is a device which uses the technology that allows details from bank cheques to be read into a computer quickly and accurately.
  • The cheque number and bank account number are printed at the bottom of each cheque in special magnetic ink using special font.
  • These numbers can be detected by an MICR reader.
  • Advantages of using MICR:
    • Offers greater security than OCR since the printed characters cannot be altered
    • There is no manual input; thus errors are reduced.
    • Even if someone scribbles over the magnetic ink fonts, they can still be read.
  • Disadvantages of using MICR:
    • Only certain characters can be read and the number of certain characters are extremely limited
    • It is more expensive method than other methods that are used in direct data entry.

OMR scanner

  • Optical Mark Recognition (OMR) is a technology that allows the data from multiple choice forms to be read quickly and accurately into a computer.
  • Special OMR forms are used, which have spaces that can be coloured in or darkened in (using a pencil or a pen). These marks can then be detected by an OMR scanner
  • Common uses of OMR are:
    • Multiple choice exam answer sheets and lottery ticket forms.
  • An OMR Scanner can read at a speed of 3000 sheets per hour
  • Advantages of OMR Scanner
    • Very fast way of inputting results of a survey
    • Since there is no typing, it is more accurate then keying the data
    • It is more accurate to draw free hand on a tablet rather than use the mouse to draw
    • Used in countries such as Japan and China where graphical characters are used instead of letters or words
  • Disadvantages of OMR Scanner
    • Specialist tablets are expensive to purchase
    • The forms need to be carefully designed to make sure that the marks or shading are positioned to gather accurate information
    • There can be a problem if the forms have not been filled in correctly and sometimes need to be correctly checked before being checked by the OMR device.
    • This is both time consuming and expensive

OCR Scanner(Optical Character Recognition)

  • OCR is a software technology that can be used to convert images (with text written on them) to an actual text file that can be edited.
  • This can be done using word processing software.
  • OCR is typically used after a page of a book has been scanned
  • The scanned image of the page is then analyzed by the OCR software, which looks for recognizable text and shape and then converts it into a matching text file.
  • Advanced OCR software recognizes normal writing as well as printed text. This is called handwriting recognition.
  • Advantages of using OCR:
    • A fast way of inputting text that has been printed on paper
    • OCR can avoid typing errors
    • OCR can recognize handwriting so it can be used on hand written notes on a tablet computer and can be converted to word processed text.
    • Avoid to type in text manually; hence this reduces the risk of RSI (Repetitive Strain Injury)
    • Since no manual data entry, number of errors is reduced.
  • Disadvantages of using OCR:
    • The system still has difficulty in reading handwriting
    • OCR is still not a very accurate technique and needs to be developed.

Barcode reader/scanner

  • A barcode is a numeric code represented by a series of lines. These lines have different thicknesses and can be read by a barcode reader/scanner
  • The most common use of barcode reader is at a POS (Point Of Sale) in a shop.
  • The code for each item to be purchased needs to be entered into the computer.
  • Reading barcodes is much quicker and accurate than typing each code using a keypad.
  • Advantages of using a barcode reader/scanner:
    • Scanning barcodes is faster than typing data manually and lesser mistakes are made.
    • Barcode enables automatic stock control
    • Barcode scanning is a tried and trusted technology
  • Disadvantages of using a barcode reader/scanner:
    • Barcode scanning is relatively expensive system to administer since every item in the shop needs a barcode and every barcode needs to be entered in the central database.
    • The system is not full proof as barcodes can be easily swapped around an item

RFID

  • Radio Frequency Identification (RFID) readers use radio waves to read and capture information stored on a tag.  The tag can be read from a distance of several metres, which is one its major advantages over the barcode system. The RFID tag is made up of two components.
    • a microchip that stores and processes information
    • an antenna that is used to receive and transmit data/information.
  • The tags can be passive or battery powered.  Passive tags use the reader’s radio wave energy to relay the information, battery powered tags use a small embedded battery to power the RFID.
  • Uses
    • Admission passes (e.g., in the theme parks RFID cards eliminate the need to scan or swipe people before ‘rides’, reducing the waiting time; it also allows the tracking of people in the theme park and certain information, such as height or age, can be stored to prevent entry to certain rides on safety grounds.
    • Libraries (books can be tracked in and out automatically by readers at the library entrance; there is no need to scan barcodes or magnetic stripe cards, making the process quicker and more accurate).
    • Livestock tracking (so that the whereabouts of each of the animals on a farm is known and it also identifies which farm owns the animal).
    • Retail (it is similar to barcodes but does not require any scanning; details, such as price, can be stored on the tag and then automatically read at a checkout – a big advantage is that several tags can be read at the same time, thus speeding up the checkout process).
  • Advantages
    • Bulk detection is possible (i.e., detect several RFID tags at the same time).
    • It is very robust and reliable technology.
    • Bidirectional data transfer (that is, it allows read and write operations to take place).
    • No line of sight contact is necessary; the tags can be read from a distance.
    • It has very fast read rate (typically < 100 milliseconds to respond).
  • Disadvantages
    • RFID is more expensive than a comparable barcode system.
    • Because RFID uses radio waves, they are relatively easy to jam or interrupt.
    • It is relatively easy to hack into the data/signal transmitted by the tag.
    • Tag collision (this happens when signals from two or more tags overlap, interfering with each other).

What are Input Card Readers?

MSR (Magnetic Strip Reader)

Many cards such as credit cards and debit cards have a strip of materials that can be magnetized on the back side

Data can be stored here in the form of magnetized dots

Usually the data stored on this strip is the same data that is shown on the front of the card

For example:

  1. Credit card number
  2. Credit card holder’s name
  3. Expiry date, etc

The strip allows the data to be input into the computer system, faster and with more accuracy than typing it in.

MSR is used to read data from the strip. This can be done by swiping the card through a slot on the reader.

Advantages of using MSR:

  • Data can be entered more quickly by swiping the card rather than typing in manually
  • The magnetic strips are not affected by water; hence they are robust
  • Usage of MSR avoids possible typing errors

Disadvantages of using MSR

  • Magnetic strips can only store a small amount of data
  • Magnetic strips can be easily damaged by magnetic fields
  • The cards cannot be read at a distance, as you have to put them in the reader and swipe them

Chip reader and Pin pad

Modern credit cards/debit cards don’t use a magnetic strip; instead they have a tiny memory chip of computer memory embedded into them.

Data can be stored in this memory and can be read by using a chip reader.

A card is inserted in the reader where metal contacts to the metal pad on the front face of the card.

The reader can then assess the memory chip and the data stored on it.

Smart cards can store much more data than a magnetic strip.

For example an identity smart card would not only store the owner’s name and card number, but will also have a digital image of the person.

Pin pad

The chip reader is often used in conjunction with a pin pad.

A pin pad has a small numeric keypad, where the personal identification number (PIN) is entered and the holder of the card can be verified as the true holder of the card.

Main use of chip reader and pin pad is to read card details when making purchases for goods or services where the card holder is present to input the Personal Identification Number (PIN)

Many cards use this system such as:

  1. ID card
  2. Phone card
  3. Credit card
  4. Debit card
  5. Door security card
  6. SIM card

Advantages of using chip reader and pin pad:

  • They have reduced fraud as the true card holder has to input their PIN
  • Chips are harder to copy as compared to magnetic strips
  • The storage capacity of data on chip is much higher as compared to that of magnetic strips

Disadvantages of using chip reader and pin pad:

  • People can forget their PIN
  • People can look when PIN is being entered. This is called as shoulder surfing.

Explain Input Sensors

  • A normal PC has no way of knowing what is happening in the real world around it.
  • It doesn’t know if it is light or dark, hot or cold, quiet or noisy.
  • A normal PC has no senses; but you can give it some by connecting sensors to it.
  • A sensor is a device that converts a real world property (for example temperature, pressure etc.) into data that a computer can process.
  • Example of sensors and properties they detect are listed below in the table:
Sensors What it detects Application (Use)
Temperature Temperature change (hot/cold) a. Central heating system

b. Automatic washing machine

c. Automatic greenhouses

Light Brightness (Light/dark) a. Automatic greenhouses

b. Automatic doors

c. Burglar alarms systems

d. Street light systems

Pressure Change in pressure a. Automatic washing machine

b. Burglar alarms systems

c. Robotics

d. Environmental monitoring

Moisture/ Humidity Wetness/dryness a. Automatic greenhouses

b. Factories where detecting moisture level is crucial (For e.g.: factories where soft drinks are manufactured)

Water level How full or empty a container is Factories where soft drinks are manufactured
Movement Movement a. Burglar alarm systems

b. Robotics

Proximity How close or far an object is All industries
Switch or button Anything that is pressing or touching it Keyboard buttons
pH Sensor How acidic or alkaline something is a. Automatic greenhouses

b. Environmental monitoring

c. Chemical processing

 

Advantages of using (input) sensors:

  • Reading taken by input sensors are generally more accurate than those taken by human operators
  • Readings are taken round the clock; there is continuous monitoring.
  • Because it is a continuous process, any necessary action or warning will be executed automatically and immediately.
  • It is comparatively cheaper as compared to manually recording all readings.

Disadvantages of using (input) sensors:

  • Faulty sensors can give faulty results

Explain input remote control

Remote controls are very common in households and industries.

A signal is sent from the remote each time a button is pressed using infrared light or radio signals

Remote controls are often used to control slideshows in presentations.

A signal from the remote can even control a computer at a distance!

This feature makes remote controls to be used while controlling Television, DVD players, Air conditioning etc.

Remote controls are also used to control start and stop machinery in industries.

Advantages of using input remote control:

  • Remote control enables devices to be operated from a small distance which makes it particularly useful for people with physical disabilities.

Disadvantages of using input remote control:

  • Signal between control and device can be easily blocked by any obstacle
  • People with limited hand/wrist movement may find it difficult to use.

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