Input devices

input device: definition

a device that can be used to put data and info into a computer

manual methods

Involve human entering data (e.g via keyboard)

automatic method

human batch jobs together and leave comp to automatically read data

automatic method: advantage

Ideal for high volume of work

criteria of choosing a device (4)

- cost

- speed

- accuracy

- reliablity

basic examples

- keyboard

- mouse

- microphone

- touch screen

graphics tablet

creates digital drawings using a stylus

OMR scanner

optical mark recognition - used to input answers or marks made by omr sheet (e.g lottery/11+)

magnetic strip reader

magnetic strip on a card hold data that is read by a machine - hotel cards

smart card reader

reads data from embedded chips - inserting a card

NFC reader

Reads data from a near field communication tag - contactless

barcode: how does it work?

represent data by using a set of parallel lines of varied width and spacing which represent different values

barcode: terminators

at start/end of code there are terminators which allow reader to know when the barcode begins/ ends - allows code to be read upside down

barcode: check digits

an extra digit/char added to end - used for validation

QR codes (quick response)

provides a link for website or app

qr codes: capacity

7089 numbers or 4296 characters

QR vs barcode

qr - higher capacity

sip/puff switch

pneumatic device that allows users to control comp systems by drawing or blowing air into sensor reader

foot switch

user controls input to system through series of pedals

braille keyboard

keys have 2 raised representations of characters - printed + braille

biometrics: what is it?

physical characteristics (fingerprint, facial images, irises + voice)

digital camera: real life use

Mastercard trialing new app allowing customers to make online purchases by taking selfie rather than password

RFID (radio frequency identification): what is it?

allows data to be transmitted wirelessly over radio waves

RFID: 2 parts to an RFID system

tag and reader

RFID: how does it work

made up of antennas for receiving + transmitting radio frequency signals and chip which processes the signals

RFID: use of radio signals

means system does not require line of sight b/w tag and reader

RFID: tag

has a unique idengifier which often stores data in a non-valtile memory cell

RFID: uses

- employee IDs

- identifying pets

- tracking farm animals

Touch screen : advs

- faster entry than mouse

- user friendly (no training)

- tamper proof to prevent keying info not wanted

Touch screen: disadvs

- limited number of options available

- dirty screen from constant touching

sensors + actuator

Records data from physical environment then control systems use sensors as analogue inputs which get converted to digital

actuators

Output device for physical motion