1. Chapter 2: Input and output devices
OCR GCSE Computing
Chapter 2: Input and output devices
OCR GCSE Computing © Hodder Education Slide 1

2. Chapter 2: Input & output
Without some way of getting data in and information out, a computer is of little value.
We often think of input and output devices in terms of those used by a modern laptop or desktop computer, but the use of input and output devices is much more varied. It includes a wide range of specialised systems used in a range of applications.
A typical home has many devices that use computer technology:
For example a washing machine has input sensors for water temperature, water level, weight and ‘door closed’.
OCR GCSE Computing © Hodder Education Slide 2

3. OCR GCSE Computing © Hodder Education 2013 Slide 3
Index to topics
Input devices
Output devices
Devices for those with specific needs
OCR GCSE Computing © Hodder Education Slide 3

4. OCR GCSE Computing © Hodder Education 2013 Slide 4
Chapter 2: Input
A typical home or office computer will have:
Keyboard for manual data entry into the computer.
Keyboards may be separate devices such as the keyboard on a desktop computer, or built in, as in a laptop, or screen keyboard as in a tablet or mobile phone.
Mouse for controlling a pointer to select items to open, move or edit.
OCR GCSE Computing © Hodder Education Slide 4

5. OCR GCSE Computing © Hodder Education 2013 Slide 5
Chapter 2: Input
Touch screen or pad
The touch pad on a laptop performs the same function as a mouse, but often has a wider range of ‘gestures’ it can recognise.
A touch screen allows the user to point directly at an item to select it to open, move or edit
OCR GCSE Computing © Hodder Education Slide 5

6. OCR GCSE Computing © Hodder Education 2013 Slide 6
Chapter 2: Input
Most home computers will also have:
Microphone for voice input to communicate or issue direct voice commands to the system.
Camera for image capture used to take photographs or as a webcam for video conferencing (using social networking for example).
Scanner to scan in documents and images from hard copy sources.
OCR GCSE Computing © Hodder Education Slide 6

7. OCR GCSE Computing © Hodder Education 2013 Slide 7
Chapter 2: Input
Computer systems used in business will also have specialist devices such as:
Bar code readers to scan barcodes from labels to identify an item and retrieve the data from a database.
RFID readers (Radio Frequency Identification).
Basically an electronic version of a bar code but one that can be read at a distance without the need for line of sight.
These are often used in shops or to track items past sensors, e.g. baggage handling in airports, toll booths, car park access or in pet identification chips
OCR GCSE Computing © Hodder Education Slide 7

8. OCR GCSE Computing © Hodder Education 2013 Slide 8
Chapter 2: Input
Automatic data collection.
Sensors are used in a wide range of applications and are used to detect a wide range of physical data.
In an aeroplane, a range of sensors are used to monitor various factors including air speed and orientation.
The control system uses this data to feed back to the control system which, in turn, responds by changing settings to ensure the system behaves as required.
OCR GCSE Computing © Hodder Education Slide 8

9. OCR GCSE Computing © Hodder Education 2013 Slide 9
Chapter 2: Input
Automatic data collection.
Hand held devices and games systems use gesture based interfaces that rely on sensors to detect motion, for example accelerometers.
Weather data is collected globally from monitoring stations using wind direction, wind speed, air pressure, humidity, rain gauges and many more sensors.
OCR GCSE Computing © Hodder Education Slide 9

10. OCR GCSE Computing © Hodder Education 2013 Slide 10
Chapter 2: Output
A typical home or office computer will have:
A monitor to display the results of processing.
These are typically LED or LCD but the technology continues to develop. Most hand held devices will have a touch screen for display so both input and output use the same device.
Speakers or headphones to play music, to obtain feedback, to use as a warning or communicate with others.
Speakers are important in hospital care where they can issue an audible warning when monitoring a patient’s vital signs.
Printer to provide hard copy portable evidence such as documents and photographs.
Often laser for documents and ink jet for high quality colour images such as photographs.
OCR GCSE Computing © Hodder Education Slide 10

11. OCR GCSE Computing © Hodder Education 2013 Slide 11
Chapter 2: Output
Computers used in specialist areas will often use a much wider range of output devices.
In design or architecture, large size plotters will be used to produce technical drawings.
OCR GCSE Computing © Hodder Education Slide 11

12. OCR GCSE Computing © Hodder Education 2013 Slide 12
Chapter 2: Output
Supermarkets will often use thermal printers because they have fewer moving parts than lasers or ink jets, and are almost silent in operation.
In aeroplanes, actuators are mechanical devices that respond to the control system by adjusting various parts of the system such as flaps or engines to maintain the required performance.
OCR GCSE Computing © Hodder Education Slide 12

13. Chapter 2: Users with specific needs
For users with specific needs there are a range of input devices used to adapt computer systems to make them more accessible.
for users with limited physical movement
Eye-typer
These detect eye movement and blinking to input data
Puff-suck switch
These allow the user to operate switches by sucking or blowing into a tube.
OCR GCSE Computing © Hodder Education Slide 13

14. Chapter 2: Users with specific needs
Voice input for those who find it difficult to operate a keyboard
uses spoken commands to control the computer and attached devices
Joystick
a joystick requires less physical movement than a mouse, so is an effective replacement for the mouse
Foot mouse for those who have limited hand / arm movement
a tracker-ball type of device operated with the foot.
OCR GCSE Computing © Hodder Education Slide 14

15. Chapter 2: Users with specific needs
Braille keyboard for those with visual impairment
This is a specialist keyboard with raised patterns on the keys that match standard braille characters
OCR GCSE Computing © Hodder Education Slide 15

16. Chapter 2: Users with specific needs
Users with specific needs may also require more specialised output devices:
Screen readers can be used to output the information on screen to aid those with a visual impairment.
Speech software reads the display on screen
Voice synthesisers provide spoken output from text input by a user who cannot communicate verbally.
Actuators provide physical movement in response to the computer and can be built into a range of devices to aid those with limited physical mobility.
OCR GCSE Computing © Hodder Education Slide 16