brief description of bar code reader which is used widely in industries, retails, libraries etc. bar code helps to provide complete details of the product within negligible time.
2. BAR CODE READER
• Bar code reader is a electronic device that can read the output printed
barcode to a computer.
• Bar code reader uses a photo sensor to convert the barcode into electric
signals as it moves across a barcode.
• The scanner measures the width of the bar and the spaces between
them.
• It then translate different pattern back into regular characters and send
to computers.
2
3. BAR CODE
• It is a optical machine readable representation of data.
• It shows data about the object to which it is to be attached.
• Bar code consist of series of black and white bars of varying
width.
• These set of lines and spaces represent a set of characters.
• These characters can be alphabetic or numerical based on
barcode reader.
3
4. BAR CODE
• The main parts of barcode include start code, end code, centre of bar and
check digit.
4
6. BAR CODE : WORKING
• When the laser from barcode reader falls on barcode it actually passes through 95
evenly spaced column.
• Any of the column that does not reflects light (dark lines) are considered as binary
digit 1 by computer.
• Any of the column that reflects light (light lines) are considered as binary digit 0 by
computer.
• Every barcode starts with a special start character and stops with a special stop
character.
• This helps to detect whether barcode is being scanned forward or backward.
• The start code represent the coding scheme used in in barcode.
6
7. BAR CODE : WORKING
• Start code will be single digit for UPC (universal product coding) and 2 digit for
EAN (European article number).
• In UPC start code 0 shows grocery, 3 shows pharmaceuticals, 5 shows coupons.
• After start code we have 5 digit which represent the manufacturer. Each
manufacture has unique number.
• Then comes the centre of bar which is represented by 2 tall bars.
• Then followed by 5 digit number which represent the product.
• The final number shows the check digit which is used to check wheather the code
has been correctly used.
7
8. CHECK DIGIT
• It is also known as check sum characters located on far right side of the code.
• PURPOSE: to verify that the information on the barcode are entered correctly.
VERIFYING THE CHECK DIGIT
Add the value of digit in odd number position.
Multiply this result by 3.
Add the value of digits in even number position.
Add the answers of step 2 and 3.
Now subtract the above result from nearest higher multiple of 10.
This value will be same with the check digit value given at the end of barcode.
If the values are not same then there is a error in barcode reader.
8
9. ADVANTAGES
Cost efficient.
Accuracy of data input.
Labour and labour charge saving.
Rapid access to total production cost.
Represent unique identity of product
9
10. DISADVANTAGES
System failure may cost more delay.
Scratched or crumble barcode may cause problem.
Data must be coded in barcode.
10
11. APPLICATIONS
• Libraries- logging borrowers and books.
• Retails- speed up checkout and ordering.
• Office- recording transaction.
• Health- ensuring correct dosage and treatment.
• Industries and laboratories.
11
