Hardware - Input devices Flashcards
1
Q
what is an input device
A
any device that allows you to pass information from the outside world into a computer system
2
Q
how does a barcode scanner work
A
- red laser light shone at a barcode to illuminate it
- white lines reflect back
- black lines absorb some light and reflect less
- sensors in scanner detect the pattern of strong and weak reflections
- reflection strength from each lie is interpreted by a microprocessor and converted into a binary value
3
Q
what 3 uses for barcode scanners used for
A
- scanning goods at supermarket checkout
- checking library books in and out
- tracking packages out for delivery
4
Q
4
why are barcodes required
A
- faster checkout queues
- reduces errors caused by manual input
- more detailed tracking information
- automatic stock control
5
Q
what does a QR code scanner do
A
- QR code is read by using a camera, commonly on a mobile device
- 3 large squares in the corners are used for alignment
- smaller black and white quares reflect or absorb light
- software on device converts each pixel into a binary value to process the image
6
Q
what does a QR code commonly contain
A
a hyperlink to an online file
7
Q
what are QR codes typically used for
A
- advertising products
- quick links to websites
- sharing contact details instantly - no need to type
8
Q
why are QR codes required
A
- hold far more information than a traditional barcode
- much quicker access
9
Q
how do 2D scanners work
A
- 2D (flatbed) scanner shines a strip of light onto a document/ photo
- strip moves over whole document , reflected light is captured using mirrors + lenses and the light intensity is measured per pixel
- information is converted into a **digital file(( to produce a digital image of the original document
10
Q
how do 3D scanners work
A
- shine a laser over the surface of an object
- records the geometry and dimensions of the object to produce a digital file
- from this file a digital model is created
- parts can then be printed using a 3D printer
11
Q
what are 2 things 2D canners are used for
A
- creating digital versions of documents and photographs
- reading passports at airports
12
Q
what are 4 things 3D scanners used for
A
- creating 3D models for use with computer-aided design (CAD)
- Dentistry
- product development
- quality inspection and research
13
Q
why are scanners required
A
simple, cheap and effective way of generating a digital representation of 2D or 3D objects for further manipulation
14
Q
how does a digital camera work
A
- as light enters lens, it falls onto the sensor which is divided up into millions of individual squares or pixels
- each pixel measures the light intensity
- this value is converted into digital data as a pixel with a single binary colour value
- image can be stored as a file on flash memory
- or a microprocessor within camera reassembles image on a screen using each pixel’s information
15
Q
what are digital cameras typically used for
A
- integrated into smartphones
- security and surveillance cameras
