topic 5 - input & output device

A device that allows data to be entered into a system

A device that allows the user to see/hear data

• Paper placed on a glass panel • Bright light illuminates the document (modern scanners use a xenon light) • Scan head moves across the document • Lens focuses on the document image • Scanned image turned into electric form by the CCD

• At airports to read passports - OCR software used to read text

• CT Scanners - MRI Scanners

• Red laser shone at barcode • Light is reflected back • Sensors detect the light back • Pattern converted to digital • Microprocessor interprets the data • Each digit made up of 2 dark and 2 white lines

• Easy to change prices on stock items • No need to price every item on the shelf • Allow for automatic stock control

• Faster checkout • Reduces errors • Itemized bills

• QR Code scanned by camera • Light reflected back • Black squares reflect less than white squares • Three large squares used to define alignment • Squares data is decoded – each square has a binary value • Processed by an app • Links to website or document • QR code can be saved and used again

• Barcode 1D QR is 2D • QR code can contain more data • QR code can be read from any angle • QR codes faster to scan than bar codes

• Fewer typing errors because one button is pressed to order an item • Speeds up time to order because fewer buttons pressed • May require less training

• A diaphragm vibrates producing an electric signal - Signal goes to a sound card and is converted into digital values

• Users voice converted into digital signal • Spoken words produce a digital pattern • Software compares wave pattern to patterns stored in memory • If they match person is identified

Spoken words recognized and shown on screen

• The software needs to be trained - Some dialects and accents can cause problems

• Cars - Siri

• Uses multiple layers of material that transmit electric current • When top layer is touched into the lower layer current changes and location is found

• Cheap to make - Can use when wearing a glove

• Conductive layer • Current flows from 4 corners – electric field created • Sensors monitor field • When screen is touched charge transferred to finger - current changes and location is calculated

• Poor in sunlight • Easily scratched • Doesn’t allow multi touch

• Good in sunlight • Durable • Allows multi touch

• Screen can crack on impact - Can’t use while wearing gloves

• Invisible grid of infra-red beams on screen 2. When screen is touched beam is broken and location is calculated

• Durable • Allows multi touch • Can use with gloves