Summary
Summary Notes on Input Devices OCR Computer Science A-Level
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Notes on Input Devices for OCR A-Level Computer Science
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All input devices transfer data from a source, outside world, to a computer. Some require greater humanintervention to generate data:
Keyboards/keypads
Pointing devices (Mouse, tracker ball etc)
Mics
Touch screens and interactive whiteboards
Barcode readers:
Two types (common) barcode system:
Universal Product Code version A (UPC-A)- Retail + warehousing- ONLY NUMERIC
Code 128- Transport and shipment tracking- Letters and numbers
QR Codes:
Quick Response codes- 2D barcodes, read by phones/tablets. Can contain: website links or info.
Scanners:
3D scanners= both industrial and medical. Many rely on technology called tomography (image into thin
slices)
Sensors:
Some data obtained directly through use of sensors. Often collect data in analogue form and require
conversion to digital data for processing. Data is usually in analogue form.
Analogue= data has no discrete value, data changes smoothly rather in exact jumps (e.g. thermometer or
speedometer)
Feedback: Constantly take readings for monitoring. If pre-set values exceeded, microprocessor will send
signal warning user. Each sensor will feed into an interface box so the microprocessor pin-points exactly
which sensor sent high value. Monitoring continues until user enters PIN/Keycode to deactivate.
Monitoring/Control:
Monitoring: computer/microprocessor will make no changes to actual process; simply report the values.
Control: Output from computer/microprocessor can alter how process is operating. Can change value of
next input received by a device, output from computer/micro-processor can affect next input it receives.
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