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B) Direct Input Systems
1. OCR Scanner
Optical Character Recognition (OCR) is a
software technology that can convert images of
text into an actual text file that can then be
edited, e.g. using word-processing software). The
result is just as if the text had been typed in by hand.
OCR is typically used after a page of a book has been scanned. The scanned image of the page is then analysed by the OCR software which looks for recognisableletter shapes and generates a matching text file.
Advanced OCR software can recognisenormal handwriting as well as printed text - this is usually called handwriting recognition.
2. OMR Scanner
Optical Mark Recognition (OMR) is a
technology that allows the data from a
multiple-choice type form to be read
quickly and accurately into a computer.
Special OMR forms are used which
have spaces that can be coloured in
(usually using a pencil). These marks can
then be detected by an OMR scanner.
Common uses of OMR are multiple-
choice exam answer sheets and lottery
number forms.
3. MICR Reader
Magnetic Ink Character Recognition
(MICR) is a technology that allows
details from bank cheques to be read
into a computer quickly and
accurately.
MICR Reader
The cheque number and bank
account number are printed at the
bottom of each bank cheque in special
magnetic ink using a special font.
These numbers can be detected by an
MICR reader.
Barcode Reader / Scanner
A barcode is simply a numeric coderepresented as a series of lines.
These lines can be read by a barcode reader/scanner.
The most common use of barcode readers is at Point-of-Sale (POS) in a shop. The code for each item to be purchased needs to be entered into the computer. Reading the barcode is far quicker and more accurate than typing in each code using a keypad.
Barcode can be found on many other items that have numeric codes which have to be read quickly and accurately - for example ID cards.
Magnetic Stripe Reader
Magnetic stripe cards store less data.
Magnetic stripe cards can be affected by
electronic and magnetic fields.
The data in a magnetic stripe card is not
secure as it is not encrypted.
Magnetic stripe card can be scratched
easily.
Electronic Fund Transfer (EFT)
EFT is a system that allows money
transfer instructions to be sent directly
to a bank’s computer system. Upon
receiving one of these instructions, the
computer system automatically transfers
the specified amount from one account to
another.
What is a Point-of-Sale?
The Point-of-Sale (POS) in a store is the place that you pay for your purchases. It is usually where the till(cash register) is located.
A typical POS will have...
A method of inputting the codes of goods purchased - usually a bar-code scanner. The codes are then used to find more information about the goods, such as price, from a database
A system to accept electronic payments - EFTPOS
A system to update the stock-level of goods whenever they are sold, and possibly to automatically re-order goods that have low stock-levels
A method of producing a receipt for purchases -usually a small dot-matrix printer
Chip & PIN' Payment System
Most bankcards no longer rely on a magnetic strip to
store customer account details. Instead the cards are
smart cards. The cards contain a small amount of
computer memory with the account information stored
inside.
Smart cards are more secure (since the data is
encrypted) and more reliable than magnetic strip cards.
When a customer wishes to pay for goods in a store, the
customer inserts the bankcard into a smart card
reader, and then types in a PIN to confirm that they are
the true owner of the card. Once the PIN is verified, the
customer can remove the card.
One of the reasons this system has proven popular is the extra level of security it provides for users:
At no time does the bankcard need to be handled by anyone other than the card owner, so with this system there is less chance of the card being stolen or copied.
The nickname for the tiny memory device inside the bankcard is a ‘chip’, and the system uses a PIN as identity proof, so the system is nicknamed ‘Chip and PIN’ in the UK.
Smart Card
It can hold more data than a magnetic
stripe card.
It cannot be affected by magnetic or
electrical fields
It cannot be scratched or damaged easily.
Data is more secure as it is encrypted.
Even though it is stolen, the person who
stole will not be able to use it unless he
knows the PIN no.
Temperature Sensor
There is a set temperature level for the greenhouse.
The temperature of the greenhouse is compared with the preset value.
Microprocessor continuously monitors the sensors.
If the sensor detects that the temperature is lower than the preset value, the microprocessor switches on the heater / shuts the windows.
If the sensor detects that the temperature is higher than the preset value, the microprocessor switches off the heater and opens the windows.
Sensor Measures Where Used
Temperature Heat or coolness Living room for central heating system
Humidity Water vapour in the air Swimming pool, greenhouse
Infra-redInfra-red radiation e.g. body
heat Security alarm systems
Light Light levels External security lights
Motion Movements Burglar alarm systems, robotics
PHAcid/alkali levels e.g. pH of
soil/waterEnvironmental experiments, river pollution
Pressure Pressure or weight Burglar alarm systems, automatic doors
Smoke Smoke in the atmosphere Offices/fire alarm systems
Sound Levels of sound Security alarm systems
TouchDetects if one object collides
into another Computer controlled robots
Analogue to Digital convertor
If the sensor is an analogue one then an analogue-to-digital convertor (ADC) will be required.
If you want to attach an analogue input device to a digital device such as a computer, you will need an analogue to digital convertor (ADC).
A good example of a computer peripheral that requires an ADC is a microphone. When you plug a microphone into a computer, you are actually plugging it into an ADC which converts the analogue signals from the microphone into digital data that the computer can then process.