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.