Input And Output Devices

1. Keyboards

1.1. used for data entry

1.2. connected to computer by USB or wireless connection (touchscreen on mobile devices)

1.3. each character has an ASCII value which is converted to digital signal when pressed

2. Microphones

2.1. used to input sound to computer

2.2. voice recognition and speech recognition system

3. Touchscreens

3.1. allow simple touch on screen

3.2. technologies: capacitive, infra-red and resistive

4. Sensors

4.1. read or measure physical properties

4.2. used in both monitoring and control applications

5. Monitoring applications

5.1. Burglar alarm system

5.2. monitoring patients in a hospital

6. Control applications

6.1. Control of street lighting

6.2. Anti-lock braking systems (on cars)

7. Interactive whiteboards

7.1. allow computer images to be displayed on a whiteboard using digital projector

7.2. allow users to write on the whiteboard

8. Acutators

8.1. Used in sensors and devices such as ADC and DAC

9. Monitors

9.1. LCD (liquid crystal display/diode)

9.2. LED (light emitting diode)

10. Light projectors

10.1. DLP (digital light projector)

10.2. LCD (liquid crystal display/diode)

11. Scanners

11.1. Two-Dimensional Scanner

11.1.1. Used at airports to read passports

11.2. Three-Dimensional Scanner

11.2.1. Used to create a 3D image of a solid object

12. Barcode readers/scanners

12.1. structure: right-hand and left-hand side separated by guard bars

12.2. application: can be used in supermarkets and libraries

12.3. numbers 0 to 9 are each represented by a unique series of lines

13. Quick Response (QR) Code

13.1. made up of a matrix of filled -in dark squares on a light background

13.2. can hold over 7000 digits

13.3. can be scanned anywhere

14. Digital Camera

14.1. can link to a computer system via USB or bluetooth

14.2. controlled by microprocessor

15. Pointing Devices

15.1. allows user to click on an icon

15.2. example: mouse and trackerball

16. Printers

16.1. Inkjet printers

16.2. laser printers

16.3. 3D printers

17. Cutters

17.1. Two-dimensional cutters

17.2. Three-dimensional cutters

18. Loudspeakers/headspeakers

18.1. sound is produced from a computer by passing the digital data through a DAC and then through an amplifier