Hardware - Input + Output devices Flashcards
what is an input device
any device that allows you to pass information from the outside world into a computer system
how does a barcode scanner work
- 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
what 3 uses for barcode scanners used for
- scanning goods at supermarket checkout
- checking library books in and out
- tracking packages out for delivery
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why are barcodes required
- faster checkout queues
- reduces errors caused by manual input
- more detailed tracking information
- automatic stock control
what does a QR code scanner do
- 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
what does a QR code commonly contain
a hyperlink to an online file
what are QR codes typically used for
- advertising products
- quick links to websites
- sharing contact details instantly - no need to type
why are QR codes required
- hold far more information than a traditional barcode
- much quicker access
how do 2D scanners work
- 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
how do 3D scanners work
- 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
what are 2 things 2D canners are used for
- creating digital versions of documents and photographs
- reading passports at airports
what are 4 things 3D scanners used for
- creating 3D models for use with computer-aided design (CAD)
- Dentistry
- product development
- quality inspection and research
why are scanners required
simple, cheap and effective way of generating a digital representation of 2D or 3D objects for further manipulation
how does a digital camera work
- 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
what are digital cameras typically used for
- integrated into smartphones
- security and surveillance cameras
why are digital cameras required
- camera on phone is smaller, lighter - largely replaces traditional, film-base cameras - chunky
- instant photographs - very accessible + quick
- easily transmitted via Wi-Fi, Bluetooth, etc.
- embedded editing software
how do keyboards work
- when key is pressed , a peg under the key is pressed into a springy layer to make contact with a conducting membrane
