Input & Output Devices

Objectives

Describe the use of contemporary methods and their associated devices for input and output.
Explain the methods and devices in contemporary computer systems and their suitability in different situations

Input Devices

An input device is a device used to input data into the computer. They can be any device that allows you to pass information from the outsdie world into a computer system. Input devices allow interaction between the user and the computer system. The interaction can be digital or analogue, depending on the type of input device.

If the device has an analogue user input it must be converted to digital once in the computer system. There are many types of input devices from standard interfaces such as keyboard or mouse, to more complicated inputs such as tracker balls and VR controllers. Examples of input devices are listed below.

Keyboards & Mice, touchpad
Concept Keyboard
2D and 3D scanners
Digital Cameras
Touch Sensitive Screen - There are two main types of touchscreen, resistive and capacitive. They both use x and y co-ordinates to indicate position when a touch is registered.
- Resistive uses two thin layers that when they make contact create a voltage and this is recorded. This is a cheaper method.
- Capacitive create an electronic field at the point of touch. Capacitive uses the energy that is conducted by the human touch to change the electric field where it touches. This is more accurate and allows for more than one touch at a time, but it is more expensive. The system will not work with gloves or pens.
Graphics Digitiser
Light Pen
Microphone
Sensor
Optical Character Recognition (OCR) - e.g. This converts printed documents into editable text documents. It does this by scanning the printed document. Software then performs pattern matching to recognised letters, numbers and characters from a database. OCR is also used by sorting machines at the Royal Mail.
Optical Mark Recognition (OMR) - This method uses a specific document, where the user can mark specific area with a thick black line. A reader then scans for black marks and notes the position on the page. If the read detects two marks in an area it only accepts one. The lottery, multiple choice exam papers and some registration systems are examples where OMR may be used.
MICR (Magnetic Ink Character Recognition) - Uses an ink that contains iron oxide and specific fonts. The MICR reader then reads this text, but as other ink does not contain iron oxide it ignores other text on the page. This is used in bank cheque reading of the sort code and account number.
Interactive Whiteboard
Barcode Readers - Barcodes are a series od dark and white parallel lines with varying thickness and are used to store product information such as County of Origin, Product Code, Manufacturer code and a Check Digit.
Quick Response (QR) code readers - A QR code contains a matrix of filled-in dark squares on a light background. Can store up to 7000 digits and can be used to store advertisements.
Webcam
Remote Control
Magnetic Stripe Reader, Chip & Pin
Games Controller, joystick, steering wheel
Tracker Ball
VR Controller

Output Devices

An output device is a device that receives information from a computer. It can be any device that can take data stored in a digital form and convert it into another format that humans can process such as sound, images or vibrations.

Graph Plotter
Printer
Speakers & headphones
Monitor, Touchscreen
Liquid Crystal Display (LCD)
Light-emitting diodes (LED) display
Inkjet and Laser Printers
3D Printers
2D & 3D Cutters
LCD Projectors
Digital Light Projectors (DLP)
Actuators

Peripherals

A peripheral is an external decvice that can be attached to a computer e.g. scanner, printer

Pointing Devices

A type of device used to control a cursor on the screen

The Input Process Output (IPO) model is the concept that programs process an input , processes that input and generates an output.

VOICE INPUT

Voice input is used to give specific instructions to the computer system and is commonly used in smartphones.
Voice print recognition analyses the pattern of a sound to authenticate a user as part of a security system.
Vocabulary dictation allows users to enter data that will be output as a text document.
- - This is of particular benefit in mobile computing and for visually or motor impaired users.

Voice INPUT

Applications

There are many applications where voice command input would be appropriate. Voice driven interfaces, also called voice recognition, can be used to issue commands to a computer system and enter data into it. e.g. via a microphone.

Vocabulary Dictation (Microphone) - A user speaks into the microphone and the system will change the spoken words into text. This is becoming more popular for everyday users. For specialist needs, additional vocabulary databases are used, such as medical or scientific.
Voiceprint recognition - This is where a person speaks into the system and it records their voice pattern. This is then digitised and stored. (REMEMBER Mr. P's Lloyds Bank Voice ID example). This is usually used as security methods. When a person speaks into the system, the voiceprint is again captured and matched against stored data.

Further applications of Voice input include:-

Mobile devices as other input devices such as using the touchscreen keyboard is small and can lead to errors / Mobile devices as a person may be using their hands for holding device so voice command input is more appropriate especially if there is a limited set of distinct commands
New cars often have a voice recognition system to operate the driver’s mobile phone and the car’s audio system. Audio devices in cars as using hands for something else and because there are a limited set of distinct commands
Automated telephone conversations – recognise numbers or limited set of distinct commands
Disabled users who cannot use a keyboard could use voice input to control the computer, typically this would be with the use of a microphone
Security entry systems as voice patterns can be used as a biometric

USES and BENEFITS

There are many contemporary uses and benefits such as

Speech recognition systems could be used by a visually impaired user to prepare a Word Processed document.
Voice-driven interface is a popular interface as it is natural for people to communicate in this way.
Speech input is much faster than keyboard input
No need to learn to type
Less danger of RSI
Reduces typing mistakes such as spelling/hitting wrong key
Keyboard takes up room on the desk
Users with a disability that prevents typing can use speech input
Hands-free advantages – can multitask
Users find talking more natural than typing.

Voice Recognition Problems

Background noise interferes with speech recognition
User when they have a speech impediment, sore throat, cold or a strong accent (British or foreign) will not be understood by a vocabulary dictation system
Users with a disability that prevents speech would need to find a different method for input
Difficult to keep data input private as people can hear what you are saying
Words that sound the same, such as ‘too’, 'to' and ‘two’ may not be recognised
Example: People who are unable to use a keyboard are able to use computers with voice recognition software. An adapted email package will accept vocabulary dictation for writing the email and also voice input commands. The voice recogntion software makes mistakes when the user is dictating the email but rarely misinterprets a command. This may to do with the software does not recognise two words that sound the same e.g. two and to, whereas for command input the system would not have any commands that sound the same.

Additional problems include:-

The system will have to be set up and trained to recognise user’s voice which might be difficult or will take time
System may not recognise colloquialisms or local dialect e.g. Words such as “ain't” and “gonna” are examples of colloquialism, as they are not used widely throughout English-speaking populations. Another good example is 'Cwtch'. In a command input system, a user would not use these types of words.
System may not recognise vocabulary dictation as background noise is more likely to interfere with words used in everyday English/Welsh language
System may not recognise proper nouns such as ‘Nantyfyllon’
Dictation could be mistaken for a command word for example open / close /save
Punctuation could be mistaken for text for example . for full stop

CASE STUDY - VOICE RECOGNITION in CARS

New cars often have a voice recognition system to operate the driver’s mobile phone and the car’s audio system. The systems have a set of pre-defined commands and can also be configured to recognise new commands or contact names for the mobile phone. Some car drivers find voice recognition systems useful and other car drivers might choose not to use the system even when it is available.

Why some car drivers find voice input for commands useful

Car driver can operate audio device without hands leaving the steering wheel / touching device
Car driver can operate audio device without eyes leaving the road / looking at device
System would have a limited set of commands so easy for car driver to learn
System would not have any commands that sound the same so would recognise most commands
System would allow car driver to create their own distinct commands and contact names for the mobile phone so driver can use system all the time not just for some functions
Allows mobile phone to used legally while driving / not have to stop car to make a call

Why many car drivers might never use the system

The driver will have to learn the pre-existing commands which will take time
The driver will have to teach the system to understand new commands which will take time
The driver will have to learn how to set up the system which might be difficult or will take time
Some drivers have used poor systems or are scared of new technology and feel that it is not worth the effort
The software may not recognise commands as background noise is more likely to interfere with words in a car
The driver might have a cold or sore throat and the system will not recognise the commands
The driver might have a speech impediment and will not be confident to use the system or it may not recognise the commands

Touch Input

Many mobile devices make use of a touch screen which as also known as a hybrid device. This is because:-

Most operating systems now use touch screens, normally capacitive touch, as the key form of input.
Capacitive touch screens work on the principle that the human body is an electronic conductor. When you press on a capacitive screen it distorts the electromagnetic field of the screen which is then measured as a change in capacitance. This is then translated into x and y coordinates for the device.

Benefits

Touch screens allow for the use of gestures, such as a swipe, to perform actions. These gestures are intuitive to the user, such as pinching to make something smaller e.g. users can also have the ability to zoom in by clicking or ‘pinch and stretch’
Touching a visual display of choices requires little thinking and is a form of direct manipulation that is easy to learn. Users have the ability to zoom in by clicking or ‘pinch and stretch’
Touch screen is very intuitive and easy to use and users may be familiar with concept - icons and clicking. It is generally regarded as easier to use as the user simply touches what is seen on the display
Whole screen on the device can be used for output so can use whole screen to watch films (or other media). No need for two separate methods, one for input and one for output therefore device can be kept small
Touching a visual display of choices requires little thinking and is a form of direct manipulation that is easy to learn
Easier hand-eye coordination than mice or keyboards. No keyboard or mouse is required.
Touch screen can be used as a keyboard or for handwriting recognition
Can be made to look like a traditional desk top or any interface with icons etc…
Some people find very small physical keyboards difficult to use
Can play interactive games by touching the screen
Less moving parts (such as buttons) so not susceptible to damage by dust or mechanical wear – robust

Touch Input - DRAWBACKS

Screen can be easily damaged/scratched
Dirty screens are difficult to read
Users must be within arm’s reach of the display
It is difficult to select small items
User's hand may obscure the screen
Screens need to be installed at a lower position and tilted to reduce arm fatigue
Some reduction in image brightness may occur.

Touch Screens

Resistive - Grid co-ordinate system e.g. (5,4); older technology than capacitive; cheaper to manufacture, made up of two thin transparent sheets; not as sharp technology; the two sheets touch when a press is made and recorded; pressure needs to be applied to create a circuit

Capacitive - Sharper Image, Multiple touch points so more responsive to touch, More expensive, more commonly used in smart phones, humans conduct electricity - needs an electrical field to be changed to register a touch, may not register a touch if the user is wearing gloves

Capacitive touch screens work on the principle that the human body is an electronic conductor. When you press on a capacitive screen it distorts the electromagnetic field of the screen which is then measured as a change in capacitance. This is then translated into x and y coordinates for the device.

Infrared - e.g. touchscreen to view and navigate a Supermarket Stock System

(Infrared) rays are sent across screen (from the edges)
Has sensors around edge/Sensors capture beams
(Infrared) rays form a grid across the screen
(Infrared) ray is broken (by a finger blocking the beam)
Calculation is made (on where beam is broken) to locate the 'touch'/Co-ordinates are used to locate the touch
Has multi touch capability

Resistive

Capacitive

Additional Reading

There are a range of touch screens available on the market today including.

As technology has progressed, the need for more interactive displays has increased (museums, smart phones, presentations, school lessons).

There are different types of touch screens such as Infra-Red, Capacitive and Resistive technology. Watch the video to find out more.

Concept Keyboards

Mouse

Laser Printer

Keyboard, Microphone, Webcam, Mouse, Bar Code Scanner

Speakers, Headphones, Printer, Projector, Monitor

OCR

MICR (Magnetic Ink Character Recognition)

Graphics Tablet

Games Controller

Button Presses, joystick movements, build in speakers, vibration feedback - Hybrid (Justify your answer)

Cash Machine / ATM Machine

I - Card Reader, Keypad, Buttons, Camera

O - Monitor, printer, speakers, actuator/motor

S - Internal Hard Drive / Memory (RAM)

OMR (Optical Mark Recogntion) - e.g. multiple choice exams, lottery tickets, school registration

Actuators

RFID tags (Radio Frequency Identification Tags). There are 2 types, passive and active. Active tags are powered by a battery.

EXTENSION

Wearable Technology - Neural Input

How wearable technology will change our lives

Understanding how programs and software recognise inputs and effectively convert this input data into processes and outputs is important. In the example below, instructions are given on how to effectively code a Raspberry Pi using Python to recognise keyboard and mouse input instructions.

How To Detect Keyboard and Mouse Inputs With a Raspberry Pi - Circuit Basics

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